Burning Question: Where Do Wheel Component Manufacturers Stand on Tire Inserts?

Feb 7, 2024
by Matt Beer  
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Trends come and go in the mountain bike world, and one of the items on that list seems to be declining are tire inserts. At one point it wasn’t uncommon to hear that most downhill racers, and occasionally even cross-country athletes, were using inserts in both the front and rear wheels.

They certainly caught on with claims of improving the lifespan of the wheel system by dispersing impact energy away from the rim and tire. In some cases, though, riders would even point towards the insert as the cause for a dead tire or wheel by pulling the tire off the rim, or the insert denting the rim itself. Inserts also don't directly protect the sidewall of the tire from being sliced either.

When Seb Stott asked in poll last year, the majority of readers said they didn't use inserts because they were heavy, costly, and to be fair, they're challenging to install and remove. Advancements in rim protection have been introduced as well, not to mention that some wheels now come with a “no questions asked” lifetime warranty so you may not be as concerned about breaking a wheel as you once were.

When I thought about what the insert offers a little further, I realized there are currently no brands out there that produce all three components of the system - the tire, insert, and rim. So I reached out to a few of the brands producing each of these components to understand what they believe are the best technologies and tactics for retaining air in your tires.







What components do you currently offer in the tire, wheel, or insert market?


DT Swiss offers complete wheelsets as well as rims. All of those products are engineered to work with the currently available tires. Those rims and wheels can all be used with a tube or tubeless setup.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


All DT Swiss rims are designed and produced to conform to the regulations of the ETRTO.

As well, all wheels/rims have their specific ASTM classification. This means that all those products will be engineered to withstand the specific loads for the intended use.

If it comes to our newest MTB family member the FR 541 rim for example, which is part of the SPLINE FR 1500 wheelset, is designed to be class leading when it comes to impact resistance as well as the specific design will help to avoid pinch flats.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


The most important thing if it comes to the tire/wheel system when we assume that high quality products will be combined and the product choice is the appropriate one to the area of application, is the correct tire pressure. This would be the best to avoid too much tire movement which may lead to an air loss.

Regarding tire inserts, first of all a tire insert is just alleviating the symptom but not the cause. So if you would like to protect your rim from impact, put more pressure in the tire! But there are reasons where an insert will be helpful. As some of the inserts will push the tire bead to the rim walls. This means that in case of an air loss the tire will not jump off the rim. This is for example the reason most of the World Cup XCO racers will use them, to have the chance to get to the feed zone fast, in case of a defect.

On the other hand a tire insert combined with very low pressure may help to prevent impact defects but will change the handling as well. So it would be cheaper and lighter to just higher the air pressure in the tire.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


When we start to develop a new rim we first of all consider the intended use and the expected forces when riding. This includes as well the forces of the tire. It’s easiest to predict the tire dimensions and the air pressure they will need. Next, we will take into consideration the available tires in the market. On the testing machines and in the real world, we will use tires from leading manufacturers and we are in contact with them for. Here, the ETRTO is the base of discussions as it regulates rims and tires regarding the dimensions which is already a good base.

How would a rim be best optimized for use with an insert?


At the moment we develop and engineer our rims to work best with high quality tires without inserts.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


There are rules for the rim/tire interface but there are no rules for inserts. Additionally I would like to mention this is not just true for bicycles but as well for any other tire/rim interface.

In an ideal world, what would be the best arrangement?


In an ideal world we would have dedicated rim/tire combinations with approved tire pressures like we see in the automotive world. This would lead to bombproof systems for a good driving performance. For those who would like to test around or try to beat times and winning races, they would need to find their own setup which might lead to defects as well.







What components do you currently offer in the tire, wheel, or insert market?


e*thirteen currently produces complete wheels, hubs, and rims, a range of tires, tubeless sealant, rim tape, and tubeless valves. We are toying with an insert now that will be raced by at least one World Cup DH/EDR team in 2024.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


There is a lot that goes into each facet of a tubeless wheel system, but the system relies on each part working well together. From what we have seen, there is no one major technology or feature that can create the perfect wheel system. It’s really a lot of small details that add up to significant improvements.

Our wheels are engineered to ensure that even when you have a bit of a wild ride and crack or dent a rim, the system won't fail, and you'll still be able to cross the finish line or ride back home safely.

Other small but significant improvements, such as slightly decreasing the tire well depth of the rim well on our Optimus trail wheels, makes tubeless setups much easier when using a lightweight trail tire.
Additionally, our rim tape is extremely flexible, making installation easy while the tape's width is based on the total profile length of the rim bed, ensuring full coverage and reliable sealing.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


For us, it is about having a system that lasts longer and consistently holds air through the life product. Each component plays a role in making that happen. First, the tape and valves need to be one hundred percent effective in preventing leaks. Second, the tire fit to the rim has to be right. Now that most rim and tire manufacturers are adhering to ETRTO, tire installation and seating of the bead are more consistent than in years past. At e*thirteen, we’re one of the few brands to make tires, rims, and tubeless components, so we have some unique insights as to how to get everything to fit and improve the rider experience.

The last part of the equation is the tire itself. Heavy-duty casings tend to have better air retention than lighter, single-ply tire carcasses. Tires are the part of the system with the most variability in the manufacturing process, so there are sometimes leaks or pinholes in the casing sidewalls. That’s why it’s important to select a sealant that not only seals punctures and small cuts at the tread but, on tire install, can migrate quickly to and seal any existing air leaks in the sidewalls.

When you add an insert to the system, the goals are usually to: 1) protect the rim and tire, 2) add lateral stability to the tire, 3) change the spring rate of the wheel-tire assembly, 4) reduce shocks transmitted to the rider.

So far, there isn’t an insert that does all of those things well at the same time, and most inserts can be extremely difficult to install. Our insert prototypes are configurable for achieving anywhere from two to four of the above goals while being easy to install and remove. We have a ways to go before finalizing the design and materials, but it will be a huge help to have it ridden and raced by some of the world’s best mountain bikers.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


Yes, but each part of the system also needs to stand on its own. The best compromises made can be difficult to hone in on, but we test internally as well as with our professional athletes in order to make those decisions.

How would a rim be best optimized for use with an insert?


First, it depends on the goal of the insert. Some inserts provide comfort and support, but according to a few of our World Cup teams, they are more likely to cause rim damage in some impact scenarios. The best thing to do is strength testing on rims with and without the insert to ensure there aren’t any unforeseen problems.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


For us, this is purely based on the fact that we need to produce wheels that perform with and without inserts. Long term, though, we are thinking about the wheel, tire, and insert that will work best as a system. Wouldn’t it be nice to completely eliminate pinch flats and dented or broken rims?

What drawbacks are there currently?


In terms of performance, we don’t feel there are drawbacks, but there are compromises to be made. For example, if you run a full-sized insert, you can run lower pressure with increased tire sidewall support and get a more damped ride feel, but the additional weight may be felt in certain riding situations, like on big jumps or manualing. Also, when using inserts, wheel handling may end up feeling less responsive.

Another compromise for riders is the ease of installation and service of wheels running tire inserts. Every rider is different and likes a variety of setups, but sometimes, the poor user experience of the installation will stop riders from getting the most out of their bikes. We don’t think this problem will be resolved as long as there isn’t a solution from a company that understands wheels, tires, and inserts as a single system. Eventually, this will happen, and a common solution will catch on in the industry. Tire inserts, especially on e-bike rear wheels, will likely become the norm as is mousse for moto. Remember when tubeless conversion used to be a nightmare for people? Now, it is pretty straightforward.

In an ideal world, what would be the best arrangement?


Our aim is to provide riders with the freedom to choose the equipment they prefer. The decision to select a particular wheel depends on your riding style and what you believe will give you an edge in performance. We want riders to have the option to choose the right wheel, set it up in the way that suits them best, and ensure we keep the air inside the tire, regardless of whether it is from e*thirteen or another brand.







What components do you currently offer in the tire, wheel, or insert market?


At Schwalbe, we’re 100% focused on bicycle tires and mainly concentrate on everything that might enhance the performance of them. So when we started working together with Stevie Smith around 12 years ago, we quickly found out that we needed some additional system in the tire to improve the reliability of both the tire and the rim, while enabling the rider to choose tire pressure freely without having to worry about snakebites or burping. This was the moment the Procore system was born. Instead of the foam inserts that are being used nowadays, Procore was a dual-chamber air system that consisted of a small diameter tube and tire that were inserted inside a conventional tubeless tire and pressurized to 60-80 psi. So if you like, Stevie basically paved the way for all current tire inserts back when he started winning on Procore.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


All of our Schwalbe Evolution Line tires are tubeless ready and compatible with all sealants currently available. Each rider can choose from a wide variety of carcass constructions that are all designed for their intended use, ranging from XC to DH with Super Race being the lightest and fastest casing for XC to Super DH which is our DH World Cup proven carcass construction.

Our Trail, Gravity and DH casing all come equipped with an Apex protection layer above the bead for improved sidewall stability and snakebite protection. Furthermore, they’re protected by a special anti-cut fabric on the sidewall called “SnakeSkin”.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


From our experience the best way to reduce the chance of losing air is an adequate choice of tires and wheels in a tubeless setup depending on the area of application and riding style. With good inserts you can surely increase puncture and burping protection to a certain extent, but based on our extensive tests we know that with clever use of material on the tire itself you can achieve a better ratio of puncture protection to weight. This has also lead to our teams drastically reducing the usage of inserts due to the addition weight, complexity but also issues that inserts introduce into the tire system. So in a nutshell, it is much more efficient to just choose a burlier tire that suits your riding.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


Absolutely. Only a tire that stays on the rim is a safe tire. Every tire we make goes through extensive testing in order to ensure that it fulfills our standards. The latter are primarily defined by the ETRTO committee, which Schwalbe has been a member of for many years, but we also have some additional internal safety standards.

To give you just one example, the blow-off safety in the norm says that a tire has to be able to withstand the indicated maximum pressure by 1,2 times for an hour. For our tests though, we ensure 1,6 times the maximum indicated pressure which is a huge safety benefit!

Other than that, we’re also involved into the development with most mayor wheel manufacturers and offer somewhat of an open-lab policy to check if their products are compatible with our tires prior to the launch in terms of safety, mounting and inflation properties. I think it’s fair to say that this has helped vastly to improve the tire-rim interface in the past couple of years.

How would a rim be best optimized for use with an insert?


There’re a few things that could be changed such as a widened flange for more compression surface or a strengthened rim well to deal with flat spots induced by stiff inserts. However, we’d actually prefer to leave this question to the rim manufacturers!

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


Thinking back to why we even have inserts, it is mainly because of reliability issues with rims and tires. So instead of adjusting tires and rims to be able to withstand inserts, why not adjust them to the actual requirements of riders?

What drawbacks are there currently?


Because our Super Gravity or Super Downhill constructions have a high resistance against snakebites it can happen in the event of a heavy impact that the tire is fine, but the rim is damaged. Replacing rims is usually more expensive and time-consuming than a flat tire. On the other hand if you are riding a setup with an insert and you have a flat on the go it can be very frustrating to fix, because tires with proper inserts can be hard to dismount. On top of that, inserts introduce new issues such as flat spots or even increased burping! We’ve actually seen inserts acting like built-in tire levers and leading to premature tire blow-offs.

In an ideal world, what would be the best arrangement?


In an ideal world, it would be great if you could enjoy the respective advantages of all the different setups/systems without the associated disadvantages. That means an ideal arrangement would be the one that is simple, relatively cheap, durable, puncture resistant, lightweight and high performing.








What components do you currently offer in the tire, wheel, or insert market?


ENVE manufacturers mountain, road, and gravel wheelsets. Currently we are not in the tire or insert market. We do however offer a product and technology within our mountain wheels that provide some of the quoted rim and flat tire protection that inserts provide.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


ENVE has developed two technologies that improve the tubeless experience in terms of pinch-flat protection and tubeless performance/user experience:

1) Hookless beads – Probably seems obvious, but the main justification for hookless is tubeless performance. Hookless allows ENVE to manufacture rims using machined metal tooling that deliver consistent and precise bead seat diameter. A precise bead seat diameter ensures that the rims bead seat meets ETRTO specifications and that tubeless tires will seal appropriately on the established rim interface.

Wide Hookless Bead – ENVE introduced the Wide Hookless Bead (WHB) in 2016 with the M60 Plus (now called the M640). This was simply a concept that having a wider/blunter leading rim edge would be less harmful to soft rubber when compressed between the proverbial rock and a hard place. This technology is now featured on 100% of ENVE wheel models including road and gravel wheel models. This technology is scaled depending on use case. For example, a road wheel may only have a 3.5mm WHB, while a gravity focused mountain wheel features a 5mm WHB.

Protective Rim Strip (PRS) – This is truly novel and the reason it hasn’t been done by anyone else is simply because you have to design a rim to go with it. It’s also oddly expensive to produce. But this is a formulated polyurethane rim strip that both eliminates the need for tubeless tape, while also eliminating the possibility of full pinch flat. The plastic rim strips snaps onto the rim establishing the bead seat diameter, and wraps over the carbon hookless beads creating a barrier between the tire and the unforgiving carbon. When impacted, the PRS dissipates the energy and is soft enough that it cannot cut through the tire. The downside is that this technology is only available on an ENVE rim, and is therefore cost prohibitive for many riders. Many have asked if they can put the strip on a non-ENVE rim, but you cannot because you have to design the rim to the strip because of the dimensions critical to tubeless performance. Meaning, if you tried to put this strip on a non-ENVE rim it wouldn’t fit, but if it did happen to fit you wouldn’t be able to put a tire on it because the bead seat diameter would be well out of spec.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


Our Protective Rim Strip is hands down the best solution on the market for someone who doesn’t want to lose air. It’s a special race technology that our DH racers have come to love and trust. It essentially guarantees that even if you happen to crack a rim, the tire will not lose air pressure because the “air chamber” is isolated from the carbon rim. The absolute most bomber tubeless set up is an ENVE wheel with Protective Rim Strip (So M730 or M930) with a gravity/DH casing tire. Short of run flat ability, we have not found a justification for inserts. Because pinch-flats are the most common type of flat we have historically experienced, and given that our technologies have made pinch-flatting a very very rare occasion, we do not run inserts.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


We look at the monetary cost and performance cost of the wheel/tire/insert system. Obviously our rim protection/anti-pinch-flat technologies are baked into the rim design. We look at lifetime cost of the wheelset/tires. Tires aren’t cheap and while ENVE wheels are priced at the higher end of the market, our customers have cited lifetime savings based solely on the fact that they wear tires out now before they flat them. Most won’t go through 5-10 sets of tires a year, but that was a reality for some of our customers and athletes prior to the introduction of the Protective Rim Strip… At $50+ for a tire, it can add up.

From a performance perspective, there is the consideration of weight. We spend so much energy refining rim designs and laminates to strike the optimal balance between weight and strength for a specific application, it doesn’t sit right with ENVE to see people spending $2000 on a high-end wheelset to then go and add up to several 100 grams to the wheelset in inserts.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


This is an interesting question because it insinuate that inserts are potentially a contributor to rim damage or failures. Over the years, we have seen and experienced some rim breakages while running inserts that seemed inappropriate for the type of impact that was experienced. This coming from personal experience and anecdotal feedback from athletes. To design a rim for inserts, you must test and develop the rim with inserts.

What drawbacks are there currently?

Nothing against inserts, but rotational weight is rotational weight. We believe that a rider looking for flat protection or ride damping benefits is better off running a tire with a DH casing than a 2 ply tire w/ an insert as the DH casing tires is likely going to provide more flat protection than the insert at a lower total weight and cost.







What components do you currently offer in the tire, wheel, or insert market?


Wheels and rims.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


Our newest addition, the new Turbine wheelset, offers our Anvil Edge tire protection design. The rim edge is widened and shaped to help prevent pinch flats. Our wheels are designed with ride quality in mind – the intent here is for riders to be able to run wheels without an insert, feel the benefits of their tire and wheel system, and still see added flat protection.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


We definitely think tire inserts have their place. Many riders want to feel the exact ride qualities of the wheels and tires they are running, and want to omit an insert, which is where our rim technologies come in. At the same time, many hard hitting riders, or people that just want to have some additional security, won’t mind the added weight and added setup of an insert.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


We design our rims primarily around making tubeless setup as simple and secure as possible, while ensuring the strength and confidence inspiring ride properties of everything from our ARC rims to our new Turbine Wheels. As there are no ISO standards for inserts, we design for the tires and rim bead connection as our primary concern in this system

How would a rim be best optimized for use with an insert?


Our engineering team would prefer I don’t give anything away.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


Again, because there are no standards here, it would be challenging to identify exactly what to design for.

What drawbacks are there currently?


Just like rims dedicated to specific tires, rims dedicated to a specific insert design would likely be under one brand, limiting rider options to single system. Most riders don’t seem to keen on limited options.

In an ideal world, what would be the best arrangement?


We’re living in a pretty option-rich time, which feels like a boon. In a world where you can buy a wheelset (plug coming – like the Race Face Turbine) that dedicates it’s engineering work to tire protection and ride feel, it means that riders looking to run without an insert, their needs are met, and riders that still want that extra protection, there is little issue or hinderance to getting an insert in there anyway since the systems are designed to work that way. There is still room for innovation in these spaces, but it’s a pretty good time to be a mountain biker.







What components do you currently offer in the tire, wheel, or insert market?


Rimpact currently offers 5 insert models for a range of disciplines and also insert compatible valves to go along with them.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


Our inserts offer all of the above improvements thanks to different design features. By reducing the speed at which an impact takes place, impact forces are reduced and damage can be mitigated entirely, up to a point. Our Pro insert uses a very dense protection layer that sandwiches itself between the tire and rim hooks to increase this force mitigation even further. The shape of our inserts ensures the maximum material is situated between the bead and sidewalls of the tyre giving the tyre something to brace against when under high cornering forces. This limits burping and increases support through lessened deflection or sidewall 'roll' and a limited tendency for the inside bead to lift from the rim. Finally, the dense foam pressed against your side walls acts as a resonance damper and mutes the trail vibrations that pass through the sidewalls and into the rim, significantly smoothing out and quieting the bike on chattery terrain.

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In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


The thickest tire, largest/most dense insert and highest air pressure will result in the least punctures. You can see that correlation in the testing Pinkbike conducted with Hunt Wheels here, and also in the multiple tests that can be found on our website as well as our competitors websites. We've also been approached by a couple of tire manufacturers who have independently conducted and concluded this same result, that with Rimpact inserts, a decrease in puncture chance is measurable and significant.

Obviously however, this setup is not ideal for an MTB use case. Riders and racers need a tire that provides traction, compliance and support simultaneously which means the upper limits of impact protection is intrinsically linked to the level of grip that rider can obtain. They also need a tire that is an appropriate weight for their discipline. A suitable analogy would be a "tire traits slider" or dial, where a rider can select where on the spectrum they want their tire to sit, between puncture proof and grip/control/weight. Whilst this is over simplified, turning the dial to maximum protection moves the slider further away from the grip end of the spectrum and moving it closer reduces the puncture protection performance. An insert effectively offers the rider an extra dial on this hypothetical spectrum, allowing them to control the grip level and the bottom out resistance of the tire independently, through pressure, tire and insert choice.

Whilst tire inserts aren't perfect, they offer benefits and performance increases that you cannot replicate with a traditional tire and tubeless set up on their own. There are no data points derived from our in house testing or from other independent tests, that we know of, that shows inserts to cause punctures. So when considering the specific question of, "What combination best reduces the chance of losing air?", the definitive answer is, a well designed insert, appropriate air pressure for the track, rider and conditions, and appropriate tire choice.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


Absolutely! The exact measurements, shape, stiffness and weight of an insert is linked to its performance and the performance of the whole system it is working within. We offer as many different sizes as we can to ensure each of the inserts fit as intended within a range of different rim and tire sizes available.

How would a rim be best optimized for use with an insert?


It's a bit of a chicken and egg scenario in that the insert is designed to be compatible with current rim designs and trends. If the trends change then we will modify or update our inserts to stay compatible and optimized. If we were to design something that requires a different rim design, then there wouldn't be any rims or customers with this newly designed rim to install it. There is a rabbit hole we could go down with completely redesigning the rim, insert and tire interface, but this means a new standard and I can already hear the furious typing coming from the comment section...

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


By "additional forces", I assume you refer to this idea that some inserts seem to redirect forces into the middle of the rim and away from the stiff hooks, causing increased damage. Whilst we don't specifically subscribe to this idea holding any weight, our Rimpact Pro Insert has a unique two stage design, it's soft on the bottom and hard on top. This means the forces are dissipated through itself and through the strong rim hooks on the edges, rather than the softer rim bed. We have seen zero evidence or claims of our inserts causing stress to this central rim section in our testing, or in the years of selling them through customer feedback.

What drawbacks are there currently?


Everything has a drawback, there's no perfect product. A DH tire is often grippier, more resilient and supportive than a trail tire. But it comes with weight, price, installation difficulty and rolling resistance penalty. If we are talking about the drawback of inserts, there are a few. They cost money, have a mass, wear out, need to be installed etc etc. The good news is the best insert offerings add far more benefits than drawbacks and their benefits are so profound that they eclipse the drawbacks. When I go for a ride, I don't expect to get a puncture. It was a regular occurance before inserts. In fact I get them so rarely since using inserts that I am very surprised to get one at all nowadays and often ride without a pump, levers or tube, (don't be like me). I know my rear wheel weighs 100g more than if I didn't run an insert, but I'd also have more rim dents, more scrap tires, more wasted trail side repair time and also a slower bike due to lower tire performance.

In an ideal world, what would be the best arrangement?


It's a boring answer but an appropriate tire, rim and insert with appropriate pressures can't be beat! This dialed set up doesn't hold the rider back and limited issues will ruin a ride. I prefer reliability and peace of mind to charge as hard as I feel confident to, so I run either DH or Enduro tires and a combination of our Pro and Original inserts to find the perfect setup for me and my particular local trails.







What components do you currently offer in the tire, wheel, or insert market?


We create and produce wheelsets for every bike discipline (mtb, road, triathlon, gravel, track).

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


Mavic pioneered tubeless back in 1999 in collaboration with Michelin and Hutchinson and introduced the Universal System Tubeless, an open license for tire and rim manufacturers to create a safe, easy, and efficient tubeless system on MTB rims.

The UST norm became official in 2019 in both world safety norms: ISO and ETRTO. The norm has been refined in 2021 and 2023 with the validation within the ISO and ETRTO norms. A wider central groove add-on to ease tire mount with wide tire beads and the no more hump locking the tire in place on the rim profile/bead will be validated in 2024.

Mavic introduced its Pinch Flat Protection (PFP) on its eBike rims since 2020. The rim aisles (walls) are machined to create an external shoulder and a wider contact surface on the top of the rim hooks (on the outside obviously). This wider surface created reduces by 20% the pinch flat/snake bites risk (less tire cuts)-see photos attached.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


Mostly circumstances: pressure, rider ability and riding technique level, speed, ground type, shock force.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


When designing a new rim, we do integrate the different use habits. For instance, on the new 2024 Deemax DH, the central groove has been enlarged (almost 2 times wider) to ease tire mount which casing, and beads are harder and wider too.

How would a rim be best optimized for use with an insert?


The pivotal aspect to take into consideration is to save enough air volume to keep getting the benefits of ride tubeless. It means keeping the ground grip, the rolling efficiency, and the riding precision. A too hard combination of tire/insert/pressure is impacting the performance of the complete system: less grip, more vibrations, less shock absorption, more muscle and material fatigue, shorter component lifetime, higher inertia meaning higher energy input to accelerate, etc.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


From both rim and tire manufacturer side everyone seems working on solutions without inserts like reinforced casing, PFP rim walls, etc. There are so many insert designs, density, volume, etc. existing that it is impossible to tell which is the best.

What drawbacks are there currently?


Most of the time it brings more difficulty to mount or put down the tire (even more with sealant and in the middle of a ride far from home) Some inserts can be pinched or compressed against the tire wall impacting badly the tire rolling efficiency. Or free floating inside the tire provoking noise, friction or move in the tire.

Inserts are not a 100% faultless anti-puncture solution. They also add weight and therefore inertia to the wheel.

In an ideal world, what would be the best arrangement?


Mastering the perfect design of both rim and tire but the tire pressure recommendations will always be an advice that has to be adapted to the riding conditions, bike, suspension settings, wheel, rider weight and skill.

A tubeless tire without sealant that would combine good rolling efficiency (thin casing) and puncture resistance (strong casing) - using a fully airtight rim without any rim tape (Fore drilling technology from Mavic) with the drilling of only the upper bridge of the rim profile. It is all about compromise on these criteria robustness/rolling efficiency/weight when coming to select the best combination. To conclude, those who are using tire inserts prioritize the resistance criteria over the weight/efficiency combo.







What components do you currently offer in the tire, wheel, or insert market?


We produce and manufacture carbon rims for mountain bikes in our Kamloops, BC facility.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


We design our rims with our proprietary hookless bead profile that seats easily but retains tires up to 60 psi with no problems. We also are using bleeding-edge carbon prepreg systems only available to North American customers that you can’t export overseas. We have a great relationship with our prepreg suppliers, and are constantly working on R&D projects to improve the fiber itself, as well as the resin system that holds it all together. These materials allow us to design rims that can take a serious beating while providing an unmatched ride feel and resisting fatigue - wear due to repeated use.

We also use relatively wide rim lips, 4-4.5mm for our enduro and DH rim offerings. We’ve found in our testing that this provides the best impact protection without excess weight, and greatly reduces the risk of snake-biting on the tire.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


We generally have found, in our experience, that running a few more PSI or a heavier casing will ultimately give you a more supported ride and impacts will be taken by the parts of the rims we have designed to take the hit.

In our team of in-house testers, nobody runs inserts. Those riders range from people who've picked up biking in the past year, all the way up to Canadian Enduro pro category podium finishers, from 120lb dirt jumpers to 220lb downhill animals. Johnny Helly, who raced the 2023 Enduro World Series U21 for us to great success, doesn't run inserts as well.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


In today's rim market, the buyer wants a rim that maximizes impact resistance without being too stiff or too heavy, and so all the weight typically added to strengthen the rim lip has to be clawed back out of an area of the rim that sees less load.

We're always going to recommend running a few more PSI or a heavier casing over an insert, but if you do want to run inserts, those that don't place a load on the center bead well are going to be our recommendation - Tannus and Huck Norris are both good options.

How would a rim be best optimized for use with an insert?


The rim wells would have to be designed to support pressure loads from the insert without severely affecting the weight or ride quality of the rim

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


In our opinion, it’s because there still isn’t a firm grasp on exactly how an insert changes the loads on a rim. Without 100% understanding how an insert changes the distribution of impact loads, it’s difficult to properly reinforce those areas. Additionally, there will almost certainly be a weight penalty as a result of needing more material to help support these different loads.

What drawbacks are there currently?


Adding an insert to the rim does two things; 1) The internal volume of the rim is reduced, 2) Redirects loads from the rim lips into other parts of the rims.

For point 1, this is similar to a coil vs air shock - the coil won't have a mechanical "ramp up" at the end of it's stroke (save for shocks with HBO) like an air shock due to the increasing spring rate as the air compresses. Inserts are similar to this - the volume occupied by the insert takes away from air volume, meaning that 24 psi with an insert is very different from 24 psi without as the air is pressing on less space. Inserts are also essentially foam springs - the deformation is a linear relationship to the load applied. As you're taking away "progressive" volume from the air and replacing it with "linear" volume of the insert, the tire also isn't able to ramp up as much as the tire is "flattened" during an impact, which means you're more likely to actually put a sharp load on the rim itself without the support of a tire filled with only air.

For point 2, inserts which snap into the bead well transfer loads to that area of the rim. Under a heavy impact, as the tire-insert-air stack compresses and load is applied to the rim lip, the insert spreads/transfers that load from directly on the rim lips to the entire upper profile of the rim. What can happen in some cases is that while the ultimate load at the rim lip is reduced by the insert, those loads are now being transferred into that center well that is meant to support pressure loads rather than sharp impacts, which can lead to failures.

In an ideal world, what would be the best arrangement?


We've been working away hard in the test lab, and are learning a lot about inserts vs no inserts, but there's still work to be done to draw some concrete conclusions. For now, we still suggest a few more PSI/a heavier casing, or an insert that doesn’t interface with the center well like Huck Norris or Tannus.







What components do you currently offer in the tire, wheel, or insert market?


Tire inserts exclusively.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


People new to CushCore know it reduces pinch flats and protects the rim. Those benefits are important, but for me, CushCore is primarily about tire dynamics. It’s a way to tune how the tire flexes and responds as you ride.

An MTB tire is like a rubber ball filled with compressed air. It’s bouncy and springy, which is great for efficient rolling, but not so good for control and stability on a rough trail. Bouncy tires bounce off obstacles. They wiggle and flex, which can be unpredictable in corners.

Ideally, we’d like a tire that rolls like an XC tire but can corner and take hits like a DH tire. It’s both elastic and resilient, firm and controlled. With that in mind CushCore was designed to reduce: pinch flats, deflection off obstacles like roots and rocks, vibration transmitted to the rider, burping by anchoring the bead to the rim, and even reduce rolling resistance on bumpy terrain. CushCore also dissipates impact energy, adds rim protection, and improves cornering traction and control, all while allowing riders the option to switch to a lighter-casing tire.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


Optimizing for a single goal is easy. We could permanently eliminate flats by making a full-profile foam insert (like a motocross bib mousse). No air, no flats. We don’t make that product because of the performance compromise, for example rolling resistance would be unacceptable. It would feel like pedaling in sand.

If preventing flats is your only goal, run a sturdy rim, DH tire, and CushCore Pro.

CushCore reduces the risk of flats in any modern MTB rim and tire combo. It does not increase the risk of any common cause of tire failure.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


Definitely. Our model range is targeted by application (XC, Trail, Pro, E-MTB). It’s no accident this mirrors the categories offered by tire manufacturers. Each model is designed for an ideal fit with the rims and tires typical for that type of riding.

Eurobike 2018
cush core insert

How would a rim be best optimized for use with an insert?


A wider rim flange helps reduce pinch flats – with or without an insert.

A rim with a reasonably deep rim well makes installation of the tire easier– with or without an insert.

For insert fitment, we consider the width between the tire beads when installed on the rim. Tire beads vary in width, so we have to consider the tire and rim combo. We want the insert under slight lateral preload when installed and inflated. Rims that are not unusually narrow or wide for a given application help us ensure insert preload is in the correct range.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


The idea that an insert can cause rim damage is a myth. A rim manufacturer brought this concern to our attention in 2019. Their rims were failing prematurely and thought CushCore a possible cause. They had not conducted any empirical testing.

We hired a third-party testing service (Wheel Energy Finland) to investigate. They tested several impact scenarios on carbon and aluminum rims, comparing tubeless setups with and without CushCore. Failure always occurred at higher impact energy with CushCore than without. CushCore increased rim durability in all tests.

What drawbacks are there currently?


We’re so used to the inherent compromises with the traditional tire and rim system. Pneumatic tires, as mentioned before, can have low rolling resistance but limited energy absorption. The air in your tires acts only as a spring, unlike your suspension which has an air spring and a speed sensitive damper. Additionally, the rim flanges create a location for a point load and are vulnerable to pinch flats and rim damage.

CushCore was designed to address these specific drawbacks of the traditional tire and rim combinations. While CushCore does add some weight, adding protection and a damper to the wheel system is well worth the performance gain.

In an ideal world, what would be the best arrangement?


A radical change in the performance of the wheel system has been ignored for decades. Current tire and rim manufacturers do not seem motivated to go beyond the existing standards. Due to high barriers to entry, there have been a limited number of startup tire companies offering something revolutionary for consumers.

Ultimately, we need a new standard for the rim-tire-insert interface. However, this is a huge project. It would involve significant product development and disrupt many of the industry’s largest manufacturers. The current design is entrenched as industry standard and adoption of a new technology would be a challenge in itself.

CushCore has succeeded in adding a true improvement to the traditional tire and rim system. There’s still room for development so we’re always considering what’s next.







What components do you currently offer in the tire, wheel, or insert market?


Roval makes XC, Trail and Enduro specific mountain bike wheels in both carbon and aluminum. Tires are available for every terrain and condition from XC race, Trail and full-on DH. Sealant and tubes are also offered to wrap up the entire package.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


Roval wheels: The best product family to talk about here is the new Traverse HD and Traverse SL II wheels we launched in July 2023. We took what we learned from Control SL and engineered multiple features into the Traverse rim shapes to give riders the best experience we could while addressing rider concerns about air retention:

1) Wide bead hooks: Both the Traverse HD and Traverse SL II rim shapes are designed with 5mm wide, flat top bead hooks on either side. This does a couple of things:
It creates a larger surface area, requiring 80% more force to pinch through the sidewall of a tire compared to our previous hook design. On Traverse Alloy, we refined the shape to prevent flat-spotting and to ensure that the bead hook dents inwards during impacts. When an alloy rim is made, you start with an aluminum bar that is then rolled into the final shape. That process changes the shape of the rim. We design the rolled shape. Outward denting is more likely to lose pressure because it releases the bead, so by designing the bead hook to dent inwards, the bead of the tire stays seated. Lastly, this beefy bead hook also contributes to the wheel’s overall impact strength to reduce cracking at the bead.

2) Rim diameter: When designing HD and SL II rim shapes, we made sure that, once the wheel is built, the tire and rim work together to ensure a proper fit for the best air retention; especially in high-energy situations like cornering. The shapes are also designed for floor-pump tubeless inflations and single-tire-lever install and removal.

3) Thread Bed Valve: The last feature, which is exclusive to our Traverse line right now, is our Thread Bed Valve. The design works with a threaded insert built into the rim at the valve hole. The valve then threads directly into the rim, torqued to 3Nm with a 5mm allen key. Rims, no matter carbon or aluminum, flex when under load. Even just sitting still. So, when you ride, the rim is flexing, compressing and expanding, almost similar to a lung. That causes compression nuts on standard valves to come loose over time because the rim’s movement creates space between the rim and the compression nut. By eliminating the compression nut from the system and threading the valve into the rim directly, we all but eliminate the risk of losing air at the valve hole. There’s also the added benefit that the nut doesn’t become glued to your rim from sealant (which I am sure many riders have experienced). Of course, if riders still want to use their own standard valve, those will fit just fine.

Specialized Tires: The interface between the rim and tire is extremely important. The tire’s molded bead shape and the rim well dimensions need to mate up just right, which ensures a seal for easily air up and retention. Using our in-house CT scanner, we can verify the best rim and tire interface under pressure, all within the dimension specs of ETRTO. Our Grid, Grid Trail and Grid Gravity casings have sidewall reinforcement, aiding in protection, support, and keeping the bead from twisting under high loads.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


Roval wheels: This is a complex question and answer because there are so many variables, and the types of riders out there are an incredibly broad spectrum. We have to start with what’s most important to the rider in any given scenario. Is it traction? Speed? Basic air retention and preventing burping? Protecting the rim at all costs? For a rider like me, 5’7’’ and 130 pounds, I rarely worry about air retention and instead prioritize traction as my most important variable. Then there is a rider at the opposite end of the spectrum. Someone like Brad Benedict, Specialized’s Senior Manager of Ride Dynamics, former World Cup DH rider, and pushing 200 pounds.

A couple of years ago, we asked Brad a specific question, “Can you ride your bike at full gas with no inhibitions or concerns that your equipment will fail?” His answer was, “No. Never.” Keeping in mind that Brad has access to all forms of wheel, tire, and insert technology and despite all of that, he still manages to rip tires off wheels. This was a clear indicator that the products available to riders fall short of rider’s performance potential. I think the reality is that different riders face different challenges and we have a lot of questions on the table and yet to answer.

Regarding inserts, we have started a deep dive into studying how rims, tires, and inserts work when energy is added to the system. We realize riders want options, so at this point our primary focus is ensuring our entire wheel and tire system are compatible with the current offering of tire inserts in the market while we continue to study the role inserts have as part of a complete system.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


Roval wheels: Absolutely. When developing rim shapes and wheel builds, we test using a wide range of tires and inserts to ensure they are compatible. We also CT-scan different combinations, conduct stiffness and energy tests on them, and do ample testing under real riders. Traverse and Control wheels are all approved to work with inserts, even with the new Traverse Thread Bed Valve.

Specialized Tires: Yes, a great example of this is when we designed the Cannibal tire. We spent an equal amount of time testing and tuning the Grid Gravity casing and apex profile using the most popular insert options, as well as without them. We tuned the tire stiffness and feel to be very consistent and compatible with either option. Our Gravity and Enduro riders run many different combinations, and tire consistency is key.

How would a rim be best optimized for use with an insert?


Roval wheels: From an engineering point of view, inserts can change load distribution under impact. Inserts also change the stiffness and energy of the tire system, which alters the impact energies a wheel sees during an impact. We definitely are working to understand these energies, like I said above. Do riders really need to spend $150 for inserts to protect their rim or hold their tire on? Our goal is to address the issues inserts set out to address through rim shapes and bead hook design, tire retention, and increasing impact strength, which makes for an overall lighter and ultimately more affordable system for riders. That’s where we are prioritizing our testing and development efforts.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


Roval wheels: As a brand, we don’t manufacture inserts. However, like I said above, it is our goal to completely understand how an insert interacts with the rim when energy is added to the system. The picture is being painted. We use our CT scanner and have created custom fixtures to exam deformation under load. We just haven’t created a way to do this while riding (but we are working on it). There are a lot of opinions out there regarding the cross sections of rims failing due to contact with the insert... but this is not something we have seen in Control and Traverse. What we really want to understand is exactly what happens when a 200lb rider cases a gap, mid-whip, and bottoms out the tire on the rim. Again, it’s more fun to ask, “how can we engineer a rim and tire combination that doesn’t require inserts in the first place?”

What drawbacks are there currently?


Roval wheels: The first and most obvious is weight. Riders take a weight penalty of 150g-290g per insert. They are also expensive at around $150 per set. The insert also creates a major performance change which, can be a good or bad thing depending on who you are as a rider. Instead of a gradual change to the system (tire size selection and air pressure adjustment, for example) the rider introduces a new variable to the system. Some riders describe this feel as “trail damping” or “ride quality.” But for some, this added spring in the system does the opposite. Again, it’s complex and depends on the individual rider.

In an ideal world, what would be the best arrangement?


Roval wheels: Would you smile if I said “We are working on it?”

Currently, there is no singular solution for every rider. However, there are solutions that give riders better options. Right now, with the products currently available, the best arrangement is finding the right wheel and tire compound/tread design/casing (and maybe insert) that suits the individual rider’s needs. We engineer our rims and tires to work seamlessly, while also ensuring our wheel and tire system is compatible with every kind of insert available, giving riders the widest range of options for what they feel is best.

I see a lot of riders out there running setups that don’t make any sense. For example, at the Cascade Dirt Cup Enduro in Bellingham, WA this last summer, I saw a rider with a set of Control SL’s (our XC wheelset), with Maxxis DHF/DHR single ply casings, and CushCore front and rear on his Forbidden Dreadnought. This rider took a 1240g XC race wheel and added 500g+ with inserts to protect against pinch flats. Now, he may have been trying to use a lighter tire with inserts to create a lower volume in the tire, but in my mind he may have been better served using a wheel intended for trail/enduro riding and a different tire casing or compound. Helping riders to better understand the tech that goes into their products is the big challenge. With a thousand combinations available, it’s not a surprise that so many riders face these issues we are discussing.







What components do you currently offer in the tire, wheel, or insert market?


Giant currently manufactures a range of own-brand mountain bike wheels that are both specced across our bike line as well as available after-market. Stand- out examples in the line-up are our lightweight carbon 30mm inner-width XCR cross-country wheels and our all-new super-durable carbon TRX trail wheels and aluminum TRA enduro wheels.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


Our all-new TRX carbon trail and TRA aluminum enduro wheels feature what we call “Wide Guard” technology which is a burly 5mm thick rim sidewall that broadens the contact point between the tire and the rim, significantly reducing the incidence of pinch flats. It also better protects the rim from damage that can occur with big impacts on sharp or square edges, all without sacrificing weight or wheel performance.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


Although tire inserts can still be an important part of a rider’s toolkit depending on the terrain and speed they’re riding, we believe that our Wide Guard rims really do away with the need for inserts for most riders on most trails. By removing heavy tire inserts and reducing unsprung weight, suspension performs better too.

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


As I say, tire inserts can still play an important role depending on riding conditions, especially in competition. From our research and testing however, we feel that although inserts will add protection, they sacrifice weight and can also lead to imbalance, especially on the front tire, reducing efficiency as the rider fights to stabilize the bike. That’s why we’ve developed wheels with thick 5mm wide rim walls, to eliminate the need for inserts for most riders – lightening up their wheels, improving their suspension performance and increasing efficiency, all the while reducing the incidence of pinch flats and impact damage.

How would a rim be best optimized for use with an insert?


This really depends on the type and design of the inserts as well as the application of the wheel.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


Since we believe that most riders under most circumstances will benefit more from not having to run inserts, from our perspective, it was more interesting to develop a rim that could reduce pinch flats and withstand impact forces without the need for inserts.

What drawbacks are there currently?


As I’ve said, inserts add significant unsprung weight to the bike, which can affect suspension performance. Likewise, inserts can also pretty significantly affect tire performance and impact efficiency. They can also be tricky and time consuming to install.

In an ideal world, what would be the best arrangement?


There’s no real right answer here; under certain circumstances, especially with the speeds and terrain found on some World Cup tracks for example, inserts can offer riders an advantage, although last season our factory team rider Youn Deniaud raced and won on the aluminum TRA wheels with no inserts. In general, for most riders on most trails we believe that the wide 5mm rim walls of the TRA and TRX wheels provide the lightest and best-performing solution to avoiding pinch flats and impact damage.







What components do you currently offer in the tire, wheel, or insert market?


Hunt Bike Wheels offer an extensive range of complete wheelsets (both alloy and carbon fibre) along with rims for covering most different riding styles within cycling. All the products have been designed with a tubeless set up in mind.

What kind of technology or features do they offer in terms of holding air - be that tire stability, rim protection, resistance to denting/cracking/burping, flat prevention, sealing properties, spoke/rim strip protection, etc?


All of our products have been designed and manufactured to ensure the rim-tyre interface meets ETRTO standards. Part of the standard states a high sided 6+/-0.5mm flange for hookless rims and a 5.5+/-0.5mm sidewall with a R0.7mm hook for hooked rims is required to ensure the best seal (provided the tyre also meets the ETRTO standard and a good sealant is used).

Rim protection wise, we design rims to be fit for use, based on their intended purpose. Within the design process of our alloy rims, we use FEA to optimize the rim, looking to replicate an impact and spoke pull through. Alongside this, we ensure to work hard on material choice (6069 T6) or carbon layup to offer this in the best way. We then validate the product through lab testing, as well as ride testing, to see it meets the high standards we set. These tests include, but are not limited to, impact tests and pressure tests, which I undertake here at our UK HQ. We also test competitor rims as it is important for us to work to develop highly performing rims and wheels.

In your experience, what combination best reduces the chance of losing air? Do you see tire inserts as a benefit or hindrance, or does it depend on the circumstances?


A combination of using an ETRTO compliant rim and compliant tyre (both appropriate for the use case of the ride) with good sealant is a great start. Pair this trio with adequate tyre pressure and you won’t go too far wrong. Checking tyre pressures using a pressure gauge before each ride to ensure the pressure is suitable, is important. If you’re not sure what tyre pressure to use, do a Google search of “tyre pressure calculator” and that will give you a good basis to adjust from. An insert may be useful if you want to run lower pressures, but it won’t completely alleviate the issue of losing air, but limit – dependent on which insert is being used. Equally in a race scenario, I can see the benefits, as you will be able to ride it out to the end of the track/repair zone, provided it is a large enough insert!

When designing a tire, rim, insert, or any combination of the three, do you take into account how a consumer might pair these options together?


As previously said, we design with the use of the wheel in mind and to ensure that the product meets ETRTO standard requirements. With ETRTO the geometry of the rim bed and internal side wall/flange/hook are constrained. This should allow the rider to use any tyre they wish.

We test in our lab with Schwalbe as we work closely with them (no inserts used), but that isn’t to say other tyre manufacturers won’t work perfectly in tandem, particularly if they are ETRTO compliant. As you have seen in your previously article we have carried out impact testing with our rims with inserts so do have some good data to work from in our development process. Inserts currently have no standard that we can meet with the design, so at present we have to bear in mind that there will be a wide range of inserts, which will be hard for us to design for them all. We do know however, Rimpact inserts fit nicely, as we have performed rider testing with our sponsored athletes.

How would a rim be best optimized for use with an insert?


This is a fairly large question! (Insert spider man meme pointing at each other between rim and insert companies) It is an area we of course consider. We currently FEA model the tyre or rim without inserts and our test methods in mind, which are based on ISO testing (we choose to significantly elevate the test standards over ISO to represent serious real-world MTB impacts). The addition of a polymer in the rim bead is of course harder to model in FEA.

Cooperation between rim and insert companies could be great to help achieve this and communicating with Rimpact is something Dan, our Technical Product Manager, has already been doing for several years when he has been inputting to our rim designs and running our athlete testing.

Why haven't we seen dedicated rims to deal with the additional forces of an insert?


The rider has the option to run a variety of different inserts which will each provide different pressures in different circumstances. As the use of an insert is optional, whereas a tyre is a necessity to ride a bike, a tyre has a consistent geometry with stresses that are more predictable and tested under ETRTO.

As part of our validation process, rider testing is a big part of this. We know that some of our riders choose to use inserts and that, for us, is valuable to know that our rims can withstand the stresses of an insert, along with any abuse our riders can throw at them.

In an ideal world, what would be the best arrangement?


From our data the current situation is not throwing up serious issues for our customers, however, there will reasonably be a few outliers. It might be interesting if ETRTO was open to wheel, tyre and insert companies alike. Standardisation would be great across the board to allow the different products to work in even better harmony. This will open the market for mountain bikers to further customize their ride and can get them shredding with more options in general.




Author Info:
mattbeer avatar

Member since Mar 16, 2001
352 articles

265 Comments
  • 195 25
 Never thought we'd see eye to eye with Cushcore dispite looking up to them as a brand, but we can confirm the 'inserts cause rim damage' falacy is a frustrating myth. Also, the article is prefaced by stating that inserts seem to be on the decline. Not only do our sales not reflect this but we've been approached by multiple top DH and EDR teams for inserts this year at riders requests, no financial drivers.
  • 55 67
flag ckcost (Feb 7, 2024 at 11:29) (Below Threshold)
 Might want to ask Schwalbe Procore about that first. Of course inserts dont cause rim damage directly, but inserts such as cushcore or rimpact that create notable tire sidewall support and mask the feeling of casing roll or rim impacts can facilitate failures by making these tell-tale signs that riders use to indicate their pressure is too low harder to identify. Not only that, rim wells were never designed to take heavy loads on most traditional rims. This was the issue procore ran into. Ive also seen rim failures inside the rim well from both cushcore and rimpact inserts due to the amount of load that the rim well experiences when these inserts are used. Bead hooks fine, crack in the rim well. You dont need to hide it.....just educate your customers about running the right tire pressure.
  • 36 10
 I'm not sure how an insert could possibly damage a rim...
I've sworn by inserts for the last 6ish years, they really do what they claim to. I have been experimenting without them a little recently, and while I've definitely had a couple of failures that I could probably have avoided, I do think tire/rim technology has gotten considerably better in the last few years. For example carbon rims with a wide bead seat and Conti's new gravity line of tires is a pretty solid setup. For aluminum rims though, and for peace of mind, an insert is still a no-brainer for me.
  • 24 1
 I think in XC (and gravel) inserts are also not declining at all. A supple tire casing is so important for low rolling resistant but comes with the trade off of being easy to flat, so inserts let riders run paper thin sidewalks with really low pressures, and if they do flat there’s a chance they can ride the insert back to the pits.
  • 58 4
 @ckcost: your first point holds weight, if the product works well it can coax riders into increasingly low pressures closer to rim failure. Luckily insert users will attest to the comfortable thud they feel when they go too far with this and the lack of damage on inspection. However, how does your point differ from a rider lowering their pressure without an insert, pushing the limits until failure occurs, often in a more catastrophic way?

In response to your second point, like Cushcore we've conducted extensive testing with multiple impact angles, forces and shapes to identify if it's possible that our inserts could in any way reduce the impact resistance of the rim or tyre. We could not achieve any results reflective of the claims. This is corroborated by two tyre manufacturers independent testing they shared with us. We also have not had a single warranty claim, feedback or image proof of such failures in conjunction with our producs. Please send them to us to allow us to improve everyone's riding experience.
  • 21 1
 @ckcost: That's just a skill issue, check your pressure every ride!
  • 8 0
 @zanda23: written off a rim because i went on a ride knowing my tyre pressure was a little low

dont do it, i promise you feel like a world class idiot.
  • 12 17
flag ckcost (Feb 7, 2024 at 12:50) (Below Threshold)
 @rimpactmtb: just to clarify - I was just stating how this myth came about. Education about tire pressure is the key, regardless if you are running inserts or not. Ive personally spoken with a cushcore employe who acknowledged this was something they needed to do a better job at educating their customers with. Just because you run an insert, it does not mean that incorrect tire pressure wont result in a broken rim. Again - not your fault, it's just clear to me how this misperception came to be.

As far as broken rims in rim wells - Not sure why you would be talking to tire mfgs about that and not rim mfgs? The rim mfg's would be the ones who would see the failures and not the tire people. Ill gladly send an image along the next time I come across one. To be fair, these failures typically are on lower end rims but the fact remains - most rims were not designed to see heavy loading directly in the rim well and inserts can cause heavy loading in the rim well on an impact that is taken direct and not focused on a single bead hook. Im sure you know, this is why Schwalbe Procore was never successful - it cracked rims in the well.
  • 5 2
 @zanda23: 100% true! I would add, check tire pressure before every ride with a digital gauge. Im honestly more diligent about checking tire pressure than lubing my chain. Many rider still do the hand check method and even "let air out at the top of the climb before the descent". Not one bit surprising that these cases can result in a cracked rim.
  • 12 4
 @ckcost: If you're running inserts to avoid flats you're doing it wrong IMO...its low on the list of benefits...and if you're not checking air pressure every ride you're for sure doing it wrong and don't ride aggressive enough to need inserts anyway.
  • 5 1
 @wolftwenty1: read my last 2 comments. I don't disagree with you. (But, I would also wager that most people buying inserts are doing so to avoid pinch flats and subsequent impact damage to rims.) For me personally, the casing support during cornering was a bigger selling point but I can get something similar by just running heavier duty casing tires. Ive run both cushcore and rimpact. Not running inserts seems to give me more tire suppleness and less of a tire pressure spike when I do take a heavy impact. Im not smart enough to do the calculations but I suspect this has to do with the air volume your tire has in it both with and without inserts. Maybe air compresses easier than the insert material up until a certain pressure point. dunno....but now im on full DH tires even on my everyday pedal bike. Even still, digital gauge tire check before every ride.
  • 2 2
 @ckcost: Yea sorry was not really directed at you specifically just the whole thread. I run DH casing + CC Pro on my park bike and Enduro bike...flat protection be damned...I want that sidewall stiffness (I disagree with your statement that you can get the same), damping and rim protection - sure I have a lifetime warranty but I'm off the bike for 2 weeks...the weight penalty is well worth the tradeoff for me. That said, I do think there is a rider level and weight of rider equation here...the average blue trail (Sea to sky blue) rider likely does not need an insert as the forces they exert on the sidewall or under big impacts are just not there...so its a total waste IMO... I also think riders in the 150 or less range even if they are quite advanced don't really need it...
  • 6 1
 @wolftwenty1: Disagree. Inserts have helped me avoid tire pinch flats on many occasions. Agree they do not help with punctures.
  • 9 16
flag PhillipJ (Feb 7, 2024 at 14:17) (Below Threshold)
 @rimpactmtb Seems plausible that inserts could cause damage because they load the rim differently. Tyres only directly load the sidewalk of the rim.

Your blanket denial that inserts can cause rim damage seems like a big call given the range of rim shapes and constructions available.
  • 27 2
 @ckcost:

BS! Rims fail. Period.

They fail a lot without inserts. They fail a lot less with inserts.
  • 6 12
flag wolftwenty1 (Feb 7, 2024 at 14:32) (Below Threshold)
 @zanda23: I dont understand how people are getting pinch flats running tubeless ...? Insert or not...
  • 12 1
 @wolftwenty1: If you hit a rock hard enough with a tubeless tire, you can cut a hole in the sidewall of your tire or even in the tread from being pinched between the rock and the rim. Lower pressures increase this risk because the tire deforms more easily, and thinner tire casing are more prone to these pinch flats. Happens all the time.
  • 5 0
 @ckcost: So of all the broken rims with inserts, what's the ratio of broken rim well vs broken bead? I've definitely broken enough rims, and at work seen hundreds more and the only well damage I've seen was from sharp object with no insert or a metal tire lever.
  • 9 0
 @MrDuck:
Let's also add up broken rims with inserts vs broken rims with no inserts.
I can tell you that my broken rim count was SIGNIFICANTLY higher before I started using inserts, and again after I experimented without them.
  • 4 1
 @ckcost: this doesn’t make any sense. Psi is psi. Cushcore isn’t going to put anymore stress on the inside of a rim well than tire pressure itself on a rim strip. Procore I could see as it bound by higher pressure and the tube casing itself. Procore was never successful as you had to drill holes in your rim, it weighed a lot, was overly complex.

A foam donut isn’t exerting more pressure on a rim bed. Inserts have saved a ton of wheels, makes the ride quality better at that, gives you so much more sidewall support at the limit of cornering grip, it also gives you the ability to run a realistic pressure for grip in technical areas.

But 25psi is going to be acting on all surfaces at the same time.
  • 4 0
 @PhillipJ: air pressure loads the entire rim. Build a wheel and measure spoke tension before and after you inflate the tire. Psi is in all directions.
  • 5 1
 @rimpactmtb love your products best insert on the market
  • 7 0
 As gnarlier riders move to emtbs for all the laps the weight of inserts will be a non-issue and the benefits will be amplified. I don’t think inserts are on the outs.
  • 3 0
 @rimpactmtb “Never thought we'd see eye to eye with Cushcore”

Is there some background here? Seems like you would agree on a lot.
  • 1 0
 @bonfire: yeah, that's why high pressures are great at protecting rims.

It's not really the same as applying force to less area via the insert.
  • 5 1
 @PhillipJ: Please help me understand how inserts apply force to less area than tire pressure. I'm not sure I understand
  • 3 0
 @TEAM-ROBOT: FYI that’s corporate for what the f*ck are you talking about. Regards. Circling back it’s up there with per my previous email. Kind regards.
  • 2 0
 I run Rimpact inserts! Have a couple of mixed sets. Really like the feel and relative ease of installation. Gotta save those rims from impacts... the damping is a bonus!
  • 1 0
 Well what in the Huck Norris!
  • 1 2
 Inserts give a rider the ability to charge harder into the chunder. Maybe they end up with a false idea of how hard they can charge an that's where the rim damage is coming from regardless of the inserts ability to protect?
No duh
  • 1 0
 I ran your Rimpact Pro and original Rimpact product and was happy with both. But I was able to flat spot a Stans EX3 that I was checking spoke tension every other ride with the Rimpact Pro running a Schwalbe Super Gravity tire. Also was able to flat spot a DT EX511 with a CC product installed. Not saying the inserts were to blame, but flat spotting an AL rim may be a side effect of a certain high force hits vs a fully bent rim. For 2023 I moved to 32 hole carbon rims and DH casing tires and did not suffer any wheel damage, but that is far from scientific.
  • 9 0
 @jessemeyers: No hidden drama, we respect what they are doing and agree with their positions. They make some cool and high performing gear. I purely meant that we have different design philosophy concerning the best way to solve the flaws of modern tubeless tyres and rims.
  • 4 0
 @rimpactmtb: ah makes sense, thanks for responding!
  • 1 0
 @PhillipJ: what on earth are you talking about? A pool noodle isn’t amplifying nor localizing load. It does the opposite it dissipates.

The end of the day wheels are consumables just like the tires that shod them. At least with alloy we can easily recycle them.

I also think people grossly overestimate how much “design” or “engineering” goes into a bicycle rim. As evident by why flats, blown tires, rim failures are still present in top tier racing. Gwin roared to his success without flats because of the FTD, that weirdly launched the whole thing and died an almost immediate death.
  • 2 2
 @TEAM-ROBOT: are you actually unsure how something denser and stiffer than air isn't the same as air???
  • 2 0
 @bonfire: you might be right and I'm not claiming otherwise. I'm just not going to take "trust me bro" from someone representing a company selling the product in question.

Inserts aren't the same as air or they'd be useless. They apply force to different parts of the rim or they'd be useless. So inserts causing rim damage seems plausible.
  • 2 0
 @rimpactmtb I use your inserts on both my of bikes and they rock!
  • 1 0
 T.H.E impacts has entered the chat
  • 2 0
 ive had myself more tyre/rim failure with inserts then without.
  • 2 0
 WeAreOne “there still isn’t a firm grasp on exactly how an insert changes the loads on a rim”

Goes on to show a firm grasp of how an insert changes the loads on a rim.
  • 1 3
 Hi. Inserts can definitely cause rim damage.
  • 3 1
 @davec113:

If they do cause damage, they certainly prevent a lot more than they cause.
  • 2 0
 @Comatosegi: When you are saying flat-spot do you mean you're denting the sidewall of the rim or actually turning a round hoop into an egg?

Inserts will help with the sidewall dents but hoop strength comes from a proper wheel build, adequate spoke tension, and a nice stiff rim.
  • 1 0
 @GTscoob: Basically where if I put the wheel on a stand the runout would be off and spoke tension would be off if the wheel was true. The insert still probably saved the rim from fully bending. And that happened with regular wheel tension adjustment, which seems to be common on Stan’s wheels.
  • 3 5
 Funny how all the rim manufacturers KNOW your and Cushcore's inserts cause rim damage. Yet the guys making foam hoops think they know more than the guys who actually engineer rims. Interesting how that works out.
  • 2 5
 @Comatosegi: Yup, I flat spotted an EX511 w/CC Pro and can't even recall where I did it. A friend sustained a serious injury from a failed DT rim that was running CC Pro. IMO the impact needs to be evenly distributed across the width of the tire, which then evenly loads the insert and transfers the force into the rim bed. There's WAY too many folks who have anecdotes about this kind of failure and pretty much every rim manufacturer knows this. Yet Rimpact and Cushcore think they know better than rim manufacturers. Won't be buying either brand of insert ever again, and imo nobody should. They are not safe.
  • 2 0
 @davec113: Are you describing landing on an even surface in which even compression of the tire is then made uneven by the insert?
  • 1 0
 @jessemeyers: No, landing on a flat, even surface. The insert is then evenly compressed, transferring load directly into the rim bed where without the insert it would have gone into the beads.
  • 1 0
 @davec113: Interesting. I think I have an extra Cushcore Pro and spare wheel I can test this with by putting it on without the tire to visualize what's happening. Hmmmmmm.
  • 4 1
 @davec113: they don’t know, they brand that said they did testing with a 3rd party was cushcore, the rest said they had “indications” from their race team but would still need to do testing. Not a single wheel brand admitted or demonstrated anything other than maybe.

You dented a 511 and didn’t know because the cushcore did its job, it dissipated the energy and acted as cushion on the impact. Without one you would have had a failure from the point load. Your lack of understanding, let alone reading comprehension shows that you’re not fit to make any judgements on what a safe product is.
  • 3 1
 @davec113: it doesn’t go into the beads, the bead is folding…

Tire pressure is omnidirectional, that’s how pressure works.
  • 1 6
flag davec113 (Feb 10, 2024 at 8:35) (Below Threshold)
 @bonfire: You have no clue who am am, now go F-off.
  • 2 1
 @davec113: ok? Why does who you are matter? Pressure doesn’t care who you are. Pressure has no direction, it’s all directions. Your argument is nonsensical and goofy.
  • 1 1
 @bonfire: air pressure is all directions. Correct. Put an insert in there and suddenly it can transfer forces differently. Like onto parts of the rim that before just had air pressure to deal with while the lip of the rim took any real hits.
  • 1 1
 @davec113: You're wrong.
  • 1 3
 @MrDuck @bonfire: Literally EVERY rim manufacturer knows I'm right. If I'm wrong so is WR1, DT Swiss, and Stans. But the noodle mfg'ers think they know better, as do you? Lol! Why do you think the related questions were asked? Now go back to your pond and stop making yourself look stupid.
  • 1 1
 @davec113: I don't know, nor could I care less who you are and where you're pulling your confidence out of. I personally know people from multiple rim manufacturers, and anytime a conversation about inserts comes up let's say with some of the WR1 guys, I've seen ZERO evidence for your claims or that it would actually damage rims. Not sure what you've read in the article, but even WR1's own statement literally speculates it "may" cause damage.
Show some evidence. So far I see a lot of arrogance, confidence but zero clue.
  • 1 1
 @davec113: Going by your standards of verifiable information, I might as well claim the rim manufacturers are against inserts to sell more rims. I know it's nonsense, definitely in the case of the free replacement rims. But it's about the same quality of information you're providing.
But what do I know, it's not like I've built wheels for some of the world's best riders and thousands of other wheels for my customers.
  • 1 3
 @MrDuck: Lol. Mechanics are not engineers. Building wheels does not require any knowledge of rim design nor does it give you any sort of insight into the interactions between an insert and a rim. Rim mfg'ers don't want to make claims that will damage another business for obvious reasons. I specifically asked WR1 about this issue myself. If you consider what asking the question in the first place implies and then read the rim mfg'er answers, it's quite clear what I'm saying is in fact the truth.
  • 1 1
 @davec113: Funny. As I mentioned, I also specifically asked WR1 about this issue myself and came with a very different answer.
I'm asking you for evidence, you just keep repeating your BS. Step it up.
I don't have to be an engineer to tell you that if I've seen a 1000 broken rims, and 0 of them had insert related damage, it's statistically significant enough to say it saves more rims than it damages. Based on the feedback of literally everyone who rides inserts.
And then there's this clown who knows better, has literally nothing to back his statements but is almost as smart as it gets. Try harder or quit it Smile
Try noticing how literally noone agrees with you yet you get all the downvotes. Ever wonder why? Is it because you're so special and know more than everyone, or...? Maybe it's a witch hunt!
  • 1 1
 @MrDuck: You seem to have A LOT invested in this and you're getting really angry. I hope I'm not costing you money, people are probably reading this and having 2nd thoughts about using inserts. I'm not going to take any more time to reply to complete idiots who think doing high school level work building wheels somehow gives them special insight into this subject.
  • 1 0
 @davec113: I have nothing invested, I'm just asking this internet warrior for ANY proof of what you're claiming. You've failed to deliver so far, not surprisingly Smile
  • 1 0
 @davec113: Its funny how you call me out as angry while all I do is ask for a proof and all you have is insults. Grow up. It's like arguing with Donald trump. Or a 3 year old.
  • 1 0
 @davec113:
I'll bite... tell us who you are.
So far your argument doesn't have a lot of provenance.
  • 144 1
 Wait I thought we were supposed to stand on our derailleurs. I can’t keep up.
  • 1 0
 Well done sir!
  • 94 1
 DT Swiss: Everything inserts solve could be solved with more air.
  • 21 6
 Yeah, I read that and now I'm considering taking the stickers off of my EX511's
  • 17 16
 @derekbnorakim: I mean it is true lol Big Grin . 30ish psi in supergravity tires (in the rear) and the ride is comfortable, grip is excelent and no sign of burping or pinch flatting.
  • 42 1
 They are right when looking at flat protection in isolation, yeah. Everyone go run dh casings with 35 psi in there and hey probably won't flat ever again.

But that would be a pretty shitty ride.

The product has to serve the hobby, not the other way around.

Best paragraph was the guy from Roval: if even with the highest end stuff the 200 pound guy still has to "take care to not break something" then there's still work to do.
  • 10 0
 at 215lbs and with local dry, rocky, loose over hard terrain the working rear tire config is no inserts, DD or DH casing tires pumped to 28+ psi to avoid rim strikes.

Inserts allowed running lower pressures which provided a better ride, traction, and handling. But didn't allow running thinner-casing tires. Swapping in a tube on the trail and wearing the insert home like a sash of shame resulted in ditching inserts altogether, and taking the DT Swiss approach. Sidewall support on DD/DH casing tires is good enough without inserts, but it'd be nice to run below 28psi in the rear. Not quite nice enough for the weight penalty on a trailbike.
  • 14 0
 @daweil: Ran 40psi, DH casing in the rear of my DH bike with a tube in it for the "don't worry about it" setup for a while, can confirm it rides a lot better at ~30psi tubeless, and even better at ~27psi with cushcore
  • 5 0
 @chrod: I’m in the same weight class and terrain I run DD and 28-30 rear and 27 upfront I have had no issues at all, the ride is great and I don’t have to wrestle with inserts.
  • 1 4
 @malca: It's obvious you've never bounced your face off an Aspen in a high speed dusty section of trail because traction gave out. I have
  • 2 0
 @blueH2Oj: Yep, looks like we converged on the same solution Wink
  • 4 0
 @chrod: We are likely riding the same trails but I'm using DH casing and Cushcore Pro in the rear and 28+ PSI. I used to run much lower pressures but over the years have increased pressure and switched to DH casing as I ride more aggressively. I also don't have to carry any tire related tools cause if anything happens enough to lose air it probably means my bike is completely trashed or I am in which case I'm walking out anyways. I have considered going without Cushcore but I'd likely need to increase to 30 PSI.
  • 5 0
 DT's response was "not made here" corporate speak 101
  • 2 0
 (All DT swiss rims BTW)
I think the ratio of air volume to pressure is key here. I have a set of DT m1700 i35 (27.5) wheels that I run WTB Vigilante 2.5/ Trail Boss 2.4' s (both light casings) on and after having ran various tire/ rim combinations on other bikes, this is still my favorite setup. I dont have to push the pressure sky high to get sidewall support and that results in a comfortable, damped but responsive feel. I'm a fat ass at 230 lbs and I get away with just 27-28 psi in the rear.
In my mind, the reason for this is the added volume of the i35 rim and the relatively large volume of the WTB tires.

One of the worst set ups I tried was an 29x i27 rim with Specialized trail casing 2.3 tires. They had to be at least 32 psi or they'd squirm really bad under load. I actually ate shit once due to this tire squirm.

Similarly, I ran Specialized DH casing tires on 29xi30 rims and had to keep the rear around 30 psi or I'd burp the rear under a hard corner. The ride feel and control on both the trail and DH tires was awful at the higher pressure. They bounced around a lot (hardtail) and ultimately left me more fatigued at the end of a long rough ride.

I would like to run inserts at least on the rear the next time I have a tire that wants to be up in the 30 psi range so that I could drop it down to 27-28 and see how that goes.
  • 2 0
 @jessemeyers: ah thanks for clarifying -- didn't realize you ran the insert still
Yeah with an insert I think I could get to 26/27 or so, maybe have a better trail feel. But so far a DD Maxxgrip without an insert is a better trade on weight.
  • 1 0
 @chrod: with the DD casings I’m getting the correct footprint in corners so I don’t feel that reducing psi would improve anything. It seems that if you aren’t getting the correct footprint (flex in the tire) to maximize grip then you should probably go down in psi. However if you are squishing beyond the prescribed footprint of the tire you should go up in psi. I’ve always looked at inserts as something that can be there to prevent damage in the case of a bad line or cased jump that would potentially dent your rim.
  • 1 0
 @chrod: I’m running Conti DH 2.4 which weigh about the same as the Maxxis DD 2.5 tires they replaced. I liked the Maxxis tires but they were not holding up (lots of pinch flats) and the sidewall wore out quickly.
  • 1 0
 @blueH2Oj: how are you measuring your footprint?
  • 1 0
 @blueH2Oj: Yeah, I have experienced this with front tires. Specifically DH casing tires, the cornering grip was pretty terrible until I found the right pressure (which was about 2 psi lower than my initial pressure)
  • 2 0
 @malca:its literally what i run. i spec all my builds with DH casing tires. and when i mean all i mean all. If i build a fully ridged XC bike, its getting DH casing. The only time i air down was for dirt like Mammoth Mountain. Its like people forgot, UCI world cup rider never used inserts prior to 2016. All the rampage guys are either tubed in or high pressure tubeless. You don't need this gimmick. especially if you are direct negatively impacting your suspension. You increase your unsprung mass.
  • 1 0
 @kroozctrl: exactly. This seems like it almost as polarizing as e-bikes vs not e-bikes. If you like the inserts run the shit out of them.
  • 2 0
 @blueH2Oj: I also think I'm not getting the right footprint, I'm running a hair too much pressure. But if I do I end up bonking rims too often. Lots of square edges around here. So for me it's not inserts and a bit less traction, or inserts and the right footprint but at a weight cost. Larger volume tires help to a point, up to 2.6".
  • 2 0
 @jessemeyers: sorry I didn’t see this. I actually discovered this after a bad injury. I got back on the bike and confidence was shot. So I hired a coach and he filmed my riding so I could work through section that intimidated me again and in that I noticed my tires were way too low I increased pressure watch new corner films and the tire flexed correctly with all tread maintaining contact. I am not a competitive rider or anything I just have time and disposable income to throw at hobbies.
  • 2 0
 @blueH2Oj: interesting. That just seems like one of the hardest things to actually measure consistently. The tires contact patch is so variable depending on how hard/fast you’re riding, whether you’re braking/cornering/climbing/jumping, how your body is positioned on the bike front/rear bias. Are you just going by feel and visual approximation?
  • 1 0
 @jessemeyers: yeah that’s about it. I also noticed through that process that I road too much pressure in my fork and too little in the rear. I am in no way a suspension expert but I was able to add tokens to the front which allowed me to comfortably reduce pressure while increase bottom out resistance. The rear shock I swapped to a larger token and increased pressure slightly. Ultimately what I’ve gotten from I’ll of this is that tire pressure and casing work in conjunction with suspension setup and if one element is off it can cause the whole system to not work correctly. All that being said I have never once thought I needed an insert. I kind of feel like they are a solution to a problem that doesn’t exist. For me anyway.
  • 1 0
 @blueH2Oj: I initially started running an insert (rear only) when I exploded a carbon rim at Snow Summit but what I found was that I really liked having it because it kept the tire from folding/burping in berms and jumps without having to run 30+ psi like I do on my bikes without an insert. The extra flat protection is nice but not the main reason I use it. They aren't for every use case tho so if you don't find yourself folding tires, getting flats, or blowing up wheels then it's definitely not worth the weight penalty. Just curious but are you mostly riding Greer?
  • 2 0
 @jessemeyers: I ride Greer and vail a lot. There are some other fun areas up towards riverside too
  • 2 0
 @daweil: Dude, I agree that was a great point - and the Roval "guy" is a girl Wink
  • 1 0
 Nice, Greer and Vail are both good spots.
  • 90 2
 "a tire insert combined with very low pressure may help to prevent impact defects but will change the handling as well. So it would be cheaper and lighter to just higher the air pressure in the tire."

These statements make no sense to me. I run inserts to allow me to use *lower* air pressure for better traction and also for comfort on the back of my hardtail. Inserts definitely change the handling, but for me they actually improve it.
  • 23 16
 Yes, when someone tells you just to put more pressure I really doubt he has ever riden mtb apart from a blue trail maybe. How in the earth can you think someone did not try higher pressure in the first place? Maybe if you are a WC DH racer you can ride everywhere with 30psi but most people do not. If we the customers say that it is more comfortable to ride with 18psi guess what, it means we want to ride with 18psi on this slow and slick trail. So thank you very much for your precious advice and go f*ck yourself.
  • 23 0
 Cheaper and lighter to prevent pinch flats and rim strikes, but ignores the issues of comfort and control. I interpreted the response as "We're the industry leader and have no intention to change the formula, so run along now."
  • 4 26
flag st-alfie (Feb 7, 2024 at 13:16) (Below Threshold)
 Makes no sense to me either. You don't "higher the air pressure". If you speak English you raise or increase it.
  • 26 0
 @st-alfie: It's almost as if English might be his second (or third) language
  • 4 1
 I’m playing around with dh rubber on the rear of my hard tail. Removed the CC. Quite like it. I get the sidewall protection / lower pressure and lower rebound characteristics of the heavier tire.
  • 3 21
flag st-alfie (Feb 7, 2024 at 15:08) (Below Threshold)
 @simcik: it doesnt surprise me that Hurt Feelings Brigade disapproves
  • 6 0
 The negative handling characteristic I found was that inserts (CC Pro) made tire folding less predictable. They give the feeling of more support but when the tire does fold it's suddenly. Going up a casing level gives similar levels of support and a more "linear" predictable feel.
  • 3 0
 @mutton: I’m in the same boat. Best move I’ve made was to ditch the cushcore and go back to Alu wheels on my hardtail. Hope you’re well bruh
  • 2 2
 Makes total sense to me. Never ran inserts as I've never needed to. Thing is, I hate the squirmy feeling from low pressures. Never run lower than 26psi.

I wOnDeR iF tHeRe'S a CorRiLaTiOn ThErE.......?
  • 1 0
 @robbiekane: haha. Twas u that got me thinking about it
  • 4 0
 @lkubica:I hate to break it to you but there are lots of non-pros running rear tires in the high 20s to 30psi. Its pretty common in rocky areas like Colorado and west in the US. I think people just assume everyone rides the same style trails as they do in their little space in the world. There's a whole world out there and trails that require different setups. I never run inserts just because i really don't like the feel of them at all. I've tried a couple times and always take them out after a ride or two. I prefer very good suspension and 28psi rear, 24psi front with DH rear and Enduro front casing tires. In the PNW or in the eastern US where its really rooty and less rocky i'll drop down to 22 front and 24 rear.
  • 52 1
 I like E13's approach. They actually admit to there being benefits of inserts while DT just spouted random corporate lingo.
  • 1 0
 I actually had a multiple spoke failure with my e13 carbon enduro (lg1En) wheelset immediately the first ride after installing a pretty low profile, insert, Mynesweeper, using same pressures and tire as previously without the liner. Anecdotally I think there was some relation ship between the events, but the rim well damage/pressure increase due to insert is an interesting proposition.
  • 1 0
 @KNBikes: there could also be a relationship between the wheel deconstruct and the wheel manufacturer, in my experience.
  • 1 0
 @BrianiGnwxI: Their carbon rims are crazy strong and tough.....I hear dozens of clacks and smacks and cracks every season at Big Sky and I've only broken one rear rim....and I'm fairly sure the tire had lost substantial pressure before hand, via sidewall slash, then flew through massive rock garden and popped tire/crunched rim. Once I replaced the OEM spokes on this same wheel set with much burlier, triple butted and brass nipples, they've been absolutely bomber....I think they should have specced them with burlier spokes from the outset and saved a lot of PR and warranty work.....they're not that light to begin with, and most people don't buy any "enduro race" wheel set with absolute minimum weight as top priority , but rather long term durability.
  • 43 6
 So I used to use insert. Stopped a few seasons ago. Just run proper casing and pressure for terrain. Also check psi every ride. All my old inserts are just collecting dust in the garage now.
  • 3 0
 Same, it seemed that unless the tire and insert were coming off regularly the sealant would dry up and cause things to stick together. A sidewall slash created all variations of the English language trailside. So I run DH casings and no insert but yesterday cracked a carbon rim, fml, I guess we will see how their replacement policy is. While I actually liked the sidewall support cushcore gave and got fairly handy at installing it, everything had to be just right. The tire and insert had to be the right temp, and a bucket to rest the wheel on
  • 2 0
 I only started running an insert (Tannus) when I gained a bunch of weight and (got up to almost 220 from 180) and dinged my rim for the first time ever. I run it exclusively in the rear wheel to keep the rim protected since I like running about 23 psi in the rear, and slightly softer casing tires. Works really well for me, but I don't think it would be 100% necessary
  • 2 0
 @CSdirt Yeah same...then i went though 3 wheels last season running dh casing tires at 30psi. Back to inserts for me!
  • 2 0
 Amen. It seems we live in the same place, and maybe our terrain doesn’t warrant it, but I don’t run inserts, either. Just check for proper tire pressure every time I ride. Stuff can happen, sure, but I haven’t had too many issues. Sometimes I wonder if guys get too wrapped up in super low pressures because it’s part of the image, brah.
  • 1 1
 @AddisonEverett: @AddisonEverett: you must live in a place with nice dirt to run 23 psi. I am 200lbs with gear on and I have to run 30psi rear plus rimpact pro to even stand a chance at my home mountain. (It's full of granite chunks the size of microwaves)
  • 26 0
 "Regarding tire inserts, first of all a tire insert is just alleviating the symptom but not the cause. So if you would like to protect your rim from impact, put more pressure in the tire!"

I was never a fan of the theory of inserts until I found myself dinging my rim frequently. I found that 22/25psi was the highest pressures I could run without severely affecting grip and feel. I finally tried tire inserts and they allowed me to run my normal pressures while drastically reducing rim impacts.
  • 6 0
 Tire size also makes a huge difference. I started experimenting with 3" front tires (which actually measured 2.8") at the same time as Chris Kovarik and we traded notes for a while. We were both stunned by the pressures we could get away with when using EXO casings on wide rims: 14 - 16 psi for him and 11 - 14 psi for me (I must be lighter than him - definitely not due to a difference in riding intensity lol ).

Obviously, there were other issues - some good, some bad - but the resistance to pinch flats was astounding.
  • 2 0
 @R-M-R: Now imagine 2.8 Magic Mary with Cushcore. That's me - even below 11 psi (@165 lbs). And this is no CC rig, it's my '24 Ragley Blue Pig driven down rocks and roots with the same speed than my fully.

It is not only grip and reliability, it is a lot more comfort and a very stable tire in fast curves. Well damped too. No puncture since > 6 months when I build it up. Driven two times in a week. On short rides even without a pump because I know that I am able to finish the ride even without air. (Which never happened so far.)
  • 1 0
 @noisyriver: Yeah, it would be interesting to experiment with the damping and lateral stability of this width range. Mine is mounted to a 36 mm rim because that's what was readily available in a light, strong rim, but the lateral stability could be better and I would like to test whether it's best to achieve that via a wider rim, insert, or more supportive casing construction.

Similarly, the undamped rebound of the tire becomes problematic when the pressure is increased. Some riders would surely want more pinch flat protection, which would have to be achieved via an insert or casing construction to avoid the rebound issues associated with more air pressure in a large tire.

The concern is that a wider rim, very large insert, and/or huge tire with stout construction can create an overly heavy system. How do you feel about these or other drawbacks of your set-up?
  • 21 2
 Nice Article. However, my anecdotal experience of taking my cushcore out for one ride and breaking my carbon rim is the gospel on this topic. ( )

I have heard people say Cushcore makes rims weaker. Has anyone's experience born this out? My experience has been the opposite.

Also I will die on the hill that installation is not hard at all with the right technique. The only issue I have had is with the uninstall.
  • 5 2
 I'm pretty sure tire installation with ProCore is easier than tubeless without anything. People always talk about tricks, fancy big pumps (or compressors) just to get their tire to seat and seal. You can install ProCore with a mini pump if you wish (so trailside if needed) and it will seal instantly.
  • 4 0
 @vinay: I have also installed cushcore trailside with a oneup hand pump. Not ideal but it is possible. I am not saying you need ~tricks~ but rather proper technique. Getting the tire on is not hard with Cushcore and three pedros levers.
  • 2 0
 @zanda23: Yeah, when talking about "tricks" I mean to say people putting their tire in a tub, to wrap a strap around it when inflating etc. I'd say proper technique should be obvious but sometimes when I read "tips" about pushing the bead down into the center channel I wonder how anyone ever bothered to try to install a tire without taking advantage of that channel. I usually don't use tire levers but I don't really use very heavy tires. I've got one wheel where I used a Spank Spike rim with two center channels where ProCore indeed is horrible so I used Pepi (as it doesn't occupy those channels). The pressure of the insert is already enough to push the tire into the rim bead so it seals quick enough. Not as instant as ProCore (where you have 3bar pushing the tire in place) but still enough for it to seat with a basic floor pump. I suppose this goes for CushCore too.
  • 3 1
 Yep, haven't had to replace a rim in several years since going to cushcore. Pretty surprised WAO isn't more of an insert booster considering their warranty policy.
  • 5 0
 Just because you run an insert, it does not mean you cant break a rim. Too low tire pressure with an insert or without an insert will both result in the same outcome.
  • 4 0
 @ckcost: Absolutely, you're correct. If the goal is to run a pressure so low that even a good insert can't protect the rim, the rim will also fail if you wouldn't have bothered running an insert.
  • 1 0
 @MorganBH: Heard rumors that their enduro teams testing had worse luck with inserts on and now they don't run them. Not sure why that is.
  • 3 1
 I've broken 5 carbon rims with inserts and 1 without. All anecdotal but I don't run inserts anymore.
  • 2 1
 @j-t-g: Same tire make, model, size, and casing? Same pressure? Comparable terrain?
  • 1 0
 @j-t-g: My anecdote is the opposite, same trails, same pressures (even a little lower with inserts sometimes), when through 2-3 rims a year without inserts, zero since using them.
  • 1 0
 @R-M-R: all bontrager carbon line 30s or kovee 30s. Almost all at Sun Peaks. All tannus inserts. Varying tires. Which is why i said anecdotal rather than scientific.
  • 1 0
 @j-t-g: Thank you for the additional information. My understanding is the early Line 30s had flaws and failed in droves; the issues were later fixed. Is it possible this was the issue, rather than the inserts? It would fit with the known issues with the rims and typical experiences of other riders.

www.bikeradar.com/reviews/components/wheels/wheel-sets/bontrager-line-pro-30-wheelset-review
  • 1 0
 @R-M-R: it was entirely MY 2021 and 2022 rims so I don't know. I haven't had any failures since removing inserts, and the one failure without at the time was a delamination without clear sign if impact.


4 out of 5 failed in the same way. Always in a fast chunky section of trail, usually flat. Never felt like a significant impact, just chunky repeated chatter at speed and then boom, the rim lets go.
  • 3 0
 @j-t-g: We got the battle of the three-letter usernames with dashes in here
  • 1 0
 @j-t-g: I didn't find tannus did much for me. I constantly flat spot rim and destory tire beads and it lessened but didn't stop with tannus. I would legit go through 4-5 rear tires (or create very intricate layer of tire plugs) a season, didn't matter casing, rim, company, pressure, nothing helped. The last one on Tannus, I somehow got a through and through snake bite on a two day old double down DHR on a rock. I'm guessing the tannus was all lubed up from sealant and was pushed sideways and out of the way.

Then I switched to Cushcore Pro and I haven't gotten a flat and only damaged a rim once when using the XC on my next bike. Sold. I'd rather stay on my bike and riding all season than driving home with a cooked tire or rim and then waiting a couple weeks for warranty.
  • 2 0
 @R-M-R: this is more likely the case, failed by the shipping container load. Same with giant TRX wheels. Absolutely shockingly poor product for 3yrs before they got it figured out.
  • 16 0
 As usual this conversation speaks about riders all being roughly the same. At 220lbs I have to choose between tire support/not burping or traction. It's always been that way - riding my tires at very high pressures to keep from constantly rim striking or burping. Until inserts. Now I can ride dual DD tires at 20/24 psi with inserts and actually get the best of both worlds. That was not possible before.
  • 1 0
 How? At 105kg with gear any form of corner at speed would burp my tyre at those pressures. Let alone just the weird, squirmy ride. 24-26 F min / 28-30min rear - My FR541 had a gnarly dent and is flat spoted now after about 5 rides - that was the day i decided to let a few PSI out of the back on a wet day - Using Panzer inserts.
  • 2 0
 @michaelbevege: 100kg here and i'm with alexsin with 20/24 using inserts no issues. You must shred suuuuuuper hard Razz
  • 1 0
 Same for me. No insert means endless flats and burps. Or Tire pressure too high for comfort and traction. Especially on the hardtail.
  • 2 0
 @michaelbevege: I’m 105kg with a cushcore and all of my dramas disappeared. Ex511 with a cushcore and a DD tire. Ride average of 3days a week year round. Probably 12-15 tires over 3 years, never a burp, never a puncture, rim is like the day I bought it. Riding all NZ has to throw at me.
  • 1 0
 @michaelbevege: It is the very reason a certain rim manufacturer has been complaining how their rims may not be up to the loads certain insert apply to the rim flanges (pulling the center channel apart). Possibly not all, but the inserts that help prevent burping do so by pushing the tire outwards. I'm using Schwalbe/Syntace ProCore. I have a small tube inside at 5bar queezing the tire against those hooks. It doesn't rely on the tire pressure (so the actual pressure in the outer tire) at all to prevent it from burping. Other inserts do so to a lesser extend but it always helps.
  • 1 0
 I think it's dependent on your terrain/riding style. I'm 240lbs and where I ride is always dry, and I prefer DH casing tires with no insert over DD/enduro casings with inserts. DH casing only is a bit lighter and i am happy with 27/31psi. No flats or burps in the year i've been running this new setup, whereas i went through 2-3 tires with punctures or sidewall tears when i was running cushcore
  • 13 2
 I don't care how manufacturers feel about inserts, I love them. I haven't slashed a single tyre or cracked or dented a single rim since I started using Rimpacts. I'm the one who has to pay for replacements so I'll run what I want.
  • 21 7
 The best thing you can put in a tire to prevent flats and rim damage: AIR
  • 33 5
 True. You also get less traction and start pinging off of stuff.
  • 7 5
 @ReformedRoadie: There is an appropriate balance between tire tread/casing selection and air pressure which will give plenty of traction, keep the tire on the rim and not result in dinging rims, pinching tires, or pinging off of stuff.
  • 4 0
 @simcik: True, and inserts change the ratios of these parameters.
  • 3 0
 @simcik: you're said it yourself: "appropriate balance". Tire pressure is a trade-off. "Plenty of traction" is just an opinion, and there are certainly benefits to going further to either end of the spectrum.
  • 3 3
 @simcik: Hard disagree
  • 13 2
 Switched from Exo+ and EX511 with Cush Core to WAO Union carbon and DD casing. Ride feel is better (and slightly lighter). No flats on either.
  • 7 0
 Similar story here. Experimented with single-ply 60 TPI with Tannus and dual-ply 60 TPI with no insert on my hardtail. Same tread. I think the Tannus setup might pedal a little better, but I definitely prefer the more damp feel of the DH casing.
  • 8 1
 IMO the moral of the story is: you're better off using a heavier casing than adding an insert of the equivalent weight difference, i.e. the extra weight can be more efficiently used by putting it in the tire itself than in an insert.
  • 5 0
 I suppose it really depends on what you're after. If you're after protection against sidewall cuts, the insert isn't going to help. Against pinch flats, I'd say either could work. Rim protection, hot debate. Lower pressures for comfort and traction, the inserts may help you get away with that. Run-flat protection (to allow you to ride something out with a flat without completely destroying rim and tire) inserts help there as well.

I personally use it for the traction and burp protection. As low as I like to run my tire pressures, I'd burp them constantly in flat corners. If I don't run an insert, I have to increase my tire pressure considerably to keep the seal intact. If I'm running a tube, I can run slightly lower pressures (as they can't burp) and after the ride I find loads of grass between tire and rim as apparently I do create a gap when cornering hard. So yeah, the 5bar inside the ProCore tube keeps the gap firmly closed no matter how low of a pressure I run inside the tire.

So yeah, there is no single "moral". Decide for yourself what would work for you and go with that.
  • 3 0
 Disagree. Heavier casings have some advantages, but also downsides. They don't offer a comparable level of damping and do almost nothing for tire retention. They mainly help with pinch flats and sideall slits. Inserts don't help with sidewall slits, but do even more for pinches.
  • 1 0
 Only tire I know it could survive with no inserts in a DH/bike park/enduro is Michelin DH casing tire,1500+ grams,slow and hard in your hands.
The tire would survive any impact but the rim not. Other DH tire casings like Maxxis,Schwable,Continental or Specialized would be flat and your rim broken.
Better try a combination works for you,maybe a crazy combo but if it works for you,nice.
In my local bike park you need any help you can get,DH casing and tire insert is almost mandatory,cos tons of sniper rocks waiting to eat your nice wheels.
Even my Enduro runs on DD front no insert,DH rear tire with Octamusse insert.
  • 5 0
 So I needed to read until the end for the punchline;

"Last season our factory team rider Youn Deniaud raced and won on the aluminum TRA wheels with no inserts"

Conclusion seems to be, buy an affordable alu wheelset and develop skills.
  • 4 0
 Yes, but how long did a set of wheels last him? One race? Would be curious to know...
  • 1 0
 top comment material
  • 2 0
 @HMBA106: that's my experience when racing enduro on ally rims.
  • 1 0
 @j-t-g: Same haha, hence the comment. I am skeptical of the notion that the world's best are somehow still smooth enough to the point where they're easier on parts then us average Joes. I mean at a certain point higher speed means harder impacts. Certainly willing to be proven wrong, however, and perhaps riding style is the biggest determinant.
  • 8 2
 broke 6 rims last year with inserts. switched off of inserts and have not broken any. I also switched to ex511s from nox farlow DH after the 6th nox failed... but it was definitely the inserts... definitely...
  • 5 0
 I too have discovered less tire and wheel failures, and the ability to run just a few less psi than required otherwise, running Rimpacts. Then I end up with better ride feel, traction & lower rolling resistance. As a result, I run them in everything now from my burly E-bike to my weight weenie trail bike (different models of inserts obviously). I no longer even carry a tube, just bacon strips and CO2s.
Even my 110# wife has them on her trail bike, front and rear. In her case, she can't trailside repair a tire and she wants to keep rolling for safety reasons in the event of a flat so I just told her to ride home slowly on the inserts.
  • 5 0
 E-thirteen, 'we make our wheels out of the softest grade of aluminum we can source, and they're super heavy, so might as well throw an insert in if it helps at all'. Not a real quote but from my experience their DH wheels are JUNK.
  • 5 1
 In an ideal world we would have dedicated rim/tire combinations with approved tire pressures like we see in the automotive world.


Yes, that’s it. The future is more policing of useless rules.
Switserland. The centre of the EU.
  • 3 0
 Approved tire pressures for automobiles are useless rules?
Also not sure about Belgium (or Switzerland) but across the pond tire pressure is not enforced in any way, you’re free to put yourself and others at risk with your unsafe equipment to your heart’s content!
  • 2 0
 @leadsledpaintrain: it is the same over here. And yes, manufacturers giving actual performance numbers could be quite helpful. Air forks typically have a sticker with the recommended pressure on them, depending on rider weight. You'd be surprised how many riders have no idea how important tire pressure is...
  • 1 0
 Switzerland and the EU are in no way related.
  • 2 0
 @Kainerm: Bet. And the amount that will spend so much time puzzling on suspension settings without having their baseline tire pressure dialed.
  • 2 0
 @GTscoob: this! My buddy just got cushcore and still runs 30 psi no matter what. Absolutely forehead smacking
  • 2 0
 @leadsledpaintrain: am I your buddy? I run inserts and still run 30-33 psi for the sidewall support I need. But I tend to float between 250-280lbs and bump jump everything so I like having that insert for popping off rocks that aren't necessarily lip shaped.
  • 1 0
 @GTscoob: you are now! *fistbump*
  • 5 1
 PB: "Why haven't we seen dedicated rims to deal with the additional forces of an insert?"

ProCore was a cooperation between Schwalbe and Syntace. I've been running the Syntace rim with ProCore since 2018 without issues.
  • 4 1
 I slept on inserts, but gave them a shot when I started to do stupid stuff on a rigid bike, again, last year... really transforms the ride of a plus tire. Corner support, bump eating, traction, no flats or rim damage yet... absolutely worth their weight. The extra rotating weight mostly fades into the background if you go back and forth between insert/no insert, but the ride feel and handling benefits are there to make you grin the whole time. Still only running them on my brick shithouse Stooge build... I found them not really adding much on my FS, for my terrain and riding style.
  • 6 3
 It's WAO response I find most interesting. They make rims and frames, and have no stake in the burlier casing vs. insert game, unless it is true that inserts exert forces on the well. They assert inserts do, and I'm inclined to believe them.
  • 3 0
 With their warranty, I would think they'd be very pro-inserts if the numbers showed that they reduce rim failures. Which, in my experience, they definitely do. Pretty interesting, actually.
  • 1 0
 @MorganBH: Exactly, why speak out against inserts if they are reducing your warranty load?

I wonder if it's the type of force that determines the outcome. If you catch a 1 cmsq area of the rim lip on a toothy rock, the inserts mitigate the impact. But if you experience a big compression on large g-out, the insert directs the force into a longer segment of the circumference of the rim well.
  • 2 0
 @half-man-half-scab: From my experience, carbon wheels fail from rock-strikes, which kind of make sense. They seem super strong in more standard loading scenarios like heavy compressions, cornering, etc. I have seen carbon frames crack from loading over time, but I've seen more break from crashes where rocks impacted the tubing.

I'd be really curious to know if they track their warranty claims failure mechanisms. It seems like something they'd want to keep track of. The two WAO rims I've broken (no inserts) were just replaced with no questions asked though.
  • 3 0
 It's a bit of a long story, so Schwalbe probably didn't feel inclined to bring it up, but the development of ProCore (I've read) was trying to better tie movement in the tyres to movement in the suspension - the undamped tyres were fully compressing prior to the suspension moving at all. After ProCore they were better coupled, yielding a better and more controlled ride. CushCore's story is very similar - rim protection is a side effect of a large volume insert meant to make the bike system behave better.
Across 4 different MTBs (XC hardtail, downcountry, Enduro and DH) I'm running inserts in all of them because I prefer the way the bikes ride with the inserts. I'm 100 kg and used to have a lot of burping, occasional pinch flatting and on the DH bike, 2 or 3 rear rim denting incidents per season running tubeless with similar tyres to what I'm running now. But with inserts in the wheels I haven't burped a tyre, haven't pinch flatted a tyre and haven't dented a rim.
Tyre grip is up a little, tyre pressures are down a little, confidence is improved and since I've never ridden 3 of those bikes without inserts I can't miss the feeling of a lighter wheel.
  • 3 0
 I didn't realise how much I was holding back in rock gardens out of puncture fear until I went to inserts (rimpacts) on my enduro bike. Also went from 5 dead tyres a year to one which also dinged my rim, but I know the rim would have been destroyed without a insert. Don't run em on my xc bike I don't aim that at rocks.
  • 3 0
 Lame article. Completely ignores eBikes. I have been riding, racing and building wheels for 30 years. I went to inserts on my eBike after crushing the rim. I built a set of Light Bicycle carbon wheels for my eBike. Installed an inset and have had zero rime damage for the last 3 years. This article is asking all the wrong questions and pandering to the industry.
  • 3 0
 As someone that raced cyclocross for years on tubular tyres, the closest I've gotten to replicating that with tubeless tyres is by using foam inserts. You can't just run lower pressures like DT Swiss says, the sidewalls fold so badly and your traction and handling get much, much worse. At very low pressure in fairly narrow tyres (33mm Challenge Baby Limus, for instance) you will fold the tyre and bounce off of every rock with a very bad noise if you don't put an insert in. With the inserts in, you can still run ~20psi (190lbs rider) with good mud grip and always make it home.


I happen to use Rimpact inserts, but I think most would give you a better experience. The cost question is a red herring. To get similar performance, I'd have to buy another set of tubular wheels, very expensive tubular tyres, then spend money on someone gluing them up, or spend days doing it myself. Roll a tyre in a hard corner and get grass stuck to the glue? Good luck re-mounting that tyre without a few days of work.

Riding home on a flat with a foam insert isn't my favourite thing, but having ridden home on a bare rim once before, I can tell you what's a better experience with confidence.
  • 10 8
 When I look at my XC rim I have. It's clear how insert can cause problem.
The rim is thick and sturdy at the bead hook where impact normally happen. However, to save weight. The carbon is really thin on the rim bed.

Without insert, an impact would happen on the rim hook. Nothing push against rim bed.
With insert, the impact force would distribute on the rim bed, where carbon is thin.

CushCore saying "insert can potentially cause damage is a myth" rule them out from my list of consideration in the future. I appreciate companies that inform people to make informed decision. Ignorance of potential issue is a big no for me.
  • 6 1
 Well, in fairness to them, they got it tested (if you believe the data) and what you are suggesting is conjecture and may not necessarily be true. While it may direct some force to rim bed, it's being damped well before that happens so not a 1:1 relationship....
  • 7 3
 @RadBartTaylor: one company, who has a strong vested interest in saying that inserts cannot cause damage to a rim, says that through independent testing, they determined conclusively that inserts can never cause damage to a rim.


Another company, that if the above held true, has no vested interest whatsoever, says inserts can cause issues.


Food for thought.
  • 5 0
 I believe Cushcore and Rimpact are saying that inserts never INCREASE the damage to the rim, they only add protection for a given impact.

They may transfer some load to the center of the rim, yes, but the rim does not fail at a lower impact force than without the insert. This is what Cushcore claim to have tested.

So for the rider this would imply that if you manage to damage your rim with an insert (for a given pressure, tire/etc), you can assume it would be well and truly destroyed without it.
  • 2 0
 @j-t-g: From what I understand from the article, the other company was a rim manufacturer whose rims apparently performed worse with insert than with. Doesn't necessarily apply to all rims. Either way, it would be interesting to see some more transparent testing to settle the issue. At this point it is one statement against the other.
  • 2 0
 @vinay: I am specifically referring to the comments of we are one above. If the statement that "inserts never cause rim damage" is true, then there's no need for we are one to recommend only certain inserts or no inserts, or otherwise make comments on redistribution of area of impact forces - after all, we are one's warranty policy is that if you break a rim when riding, they will help you out. There is no discussion of assigning blame to rider or manufacturer or tire or insert in that scenario.
  • 1 0
 @j-t-g: I actually didn't see the we are one comments - so fair point and what the OP must have been commenting on.....it reads like it is his opinion. I'd like to know a bit more about their comments to be fair - have they actually seen failures or is it based on modeling the forces I wonder?
  • 3 1
 I began running an insert in my rear tire last year and couldn't believe how good it felt. Like another 10mm of sus and soaks up all the small bumps. Surprised the market has turned the other way but I get the concerns on weight, cost, installation etc
  • 2 0
 Interesting variety of responses in the article. The great thing about inserts is: nobody is forcing you to ride them. For me, they seem to be a downstream fix for not having the right combo of tire casing, size, pressure, spoke tension, etc. I'd rather solve that puzzle, but inserts are a better option than sliding out and denting rims.
  • 2 0
 Stiffer sidewall with lower pressure and wheel protection is why you run them…not for flat protection. Sure the rims have warranties but then I can’t ride for 2 weeks. I’ll take the weight penalty all day long for that tradeoff.
  • 2 0
 One aluminum hoop bent beyond repair with insert. One enduro carbon hoop cracked with insert. One downhill carbon hoop cracked with insert. Zero flats or cracked wheels since I ditched the tire inserts on the advice from my wheel builder.
  • 2 0
 There is a multitude of reasons for inserts such as there is a multitude of reasons against inserts. Just always know how to justify your current decision in case somebody is judging you either because you run inserts - or because you don't. Luckily there are options and no rules.
  • 2 0
 When I was riding mainly 26, on the rear I had DH casing (+1200grm) + DH tube (+400grm) + 40psi. It was heavy (very heavy), but it stopped any tire problem (flats/burps/what ever).

Then.. as time moved on, and Schwalbe released their PROCORE, I jump on the boat, since it was something well proven on MOTO (Enduro).

With Procore (±400grm), I could use EXO+ tires (±1000grm), runing on the tubless system pressures from 13 psi (yes... thirteen), up to 30 psi on the rear!
Up front, pressures where between 10psi and 25psi.
At lower pressures, the grip (42a & supersoft compounds) it gave to the tires, was mind blowing. I could cross wet and muddy tree roots, at 45°, without major body english.
The inner tube+tire, pumped at 70psi, would grab the sidewalls of the tire, as a shark, and never had a tire burp.

The confidence in the system grew on me, and on all rides, I was leaving any spare tubes or pumps in the car (almost 500grm).
And during this time, the only puncture I had, that wasn't fixed with Stans squirming out of the hole, it was ok, since the inner tube and tire, let me ride back, without any major issue, and having some fun, how the bike handled (cutties were so easy to perform...).

So...


BRING BACK PROCORE!!!!!!
  • 2 0
 @wolftwenty1: as a 150lb rider, I have had ZERO issues with rims/wheels since I started riding with inserts. I have one bike with CC pro, and one with Rimpact pro installed front and rear (both bikes I run 21 up front, 25 rear). List of benefits I enjoy from this set up: no rim damage, reduced chatter/damped ride, better cornering support (I have folded rims like tacos cornering prior to using them), and one of the best aspects saving money. I've gone through less tires and rims because of this. At my weight/riding style I would have to run about 30psi rear, 27+ front to prevent equipment damage. This resulted in a much less fun ride experience.

In the end to each their own when it comes to their set up. Your opinion on other riders 'need' for them based on their weight may be one of the most ridiculous opinions I've read on here in quite a while.
  • 5 1
 But... how else can the shreddy kids ride at 5 psi and destroy berms with sick schralpies? Bruh?
  • 2 1
 I still stand at:

Why would I pay the price of a another tyre to fix issue with my wheel and tyre?
Why not bond a stripe of foam to the sidewall where it would be effective. Less mass, easier installation, pay for one part only.
If you are slashing DH casing than maybe.
If desired casing only comes with too draggy compound and thread, that lets shout at tyre manufacturers.

For me... since I started using pressure gauge before every ride snake bites and bend rim flanges stopped.
  • 3 0
 Is the first photo there for irony--rockin' lightweight & fast Aspens with inserts--does that not negate the high points of the Aspens?!
  • 3 0
 I imagine you will still get the benefit of low rolling resistance of the Aspens. But yeah, if you are going to seek out the absolute lightest XC tire I dont know if inserts are the logically next choice.
  • 2 0
 The same factors can apply at both ends of the weight & durability spectrum. An enduro rider might choose between a DH casing without insert vs. enduro casing with insert. Similarly, a XC rider might choose between a mildly reinforced casing without insert vs. naked casing with insert. There are lightweight inserts available for XC - even for road. Tubolight and Panzer make XC inserts with claimed weights under 100 g and Tubolight's road insert is claimed to weigh less than 20 g.
  • 3 1
 The time lost, and frustration had in my garage installing and removing inserts, far exceeds any inconvenience of dealing with flat tires on the trail. I'll take my chances. Oh and no weight penalty had as well.
  • 1 0
 I have been using rimpact front and rear and they make large-ish tyres on unfashionably narrow rims, stable. A heavier sidewall and more air wouldn't be a viable alternative. Also run a sidewall weight down on what I would run without inserts.
  • 3 1
 Funny that Roval says they want riders to have options, but claim that running an insert voids their warranty. Their R&D team should synch up with their warranty department to get the messaging straight.
  • 1 0
 Where are you seeing that messaging? It appears that all their current wheels appear to say that they're compatible with insets. Have you had warranty deny claims because of insert use? I work in a shop that sells and consequently warranties Roval and Reserve wheels and am genuinely curious.
  • 5 0
 DH wheels, DH tires, 30psi + cushore.. I need to pick better lines...
  • 2 0
 No you don't, you're doing it exactly right.
  • 2 0
 Learned my lesson this summer from not running inserts. Found a sweet spot with Tannus armour + Super Trail Schwable rear and Super Gravity front with no insert. PITA to install but super damp ride feel and very durable
  • 1 0
 Running inserts can embolden riders to take questionable lines at higher speeds. This is the only way I can imagine inserts contributing to rim damage. Otherwise the companies making these allegations should provide some theories or examples of how that insert-related damage can occur. Would be fascinating to understand the mechanisms behind it if that really is the case.
  • 1 0
 The insert or not debate is the new " pick a wheel size and be a dick about it" I like inserts on the MTB as I prefer to un lower pressure as I want all the grip the tires can muster as I progress into steeper terrain. I run them on my "gravel bike" because it is an older CX bike that won't allow for wider then 40cc tires, as such the added protection of the insert lets me ride a little harder without pinch flats. As an aside not a ton of DH sidewall gravel tires available..... yet.
  • 2 0
 What pressure/tire casing are people running with/without inserts? I run ~22 psi rear with a Tannus insert and ~18psi front with no insert on EXO casing tires. I ride steep/gnarly trails but am not particularly fast.
  • 1 0
 I'm really close to that setup just a tiny touch more front and rear (24/20) also only have the Nukeproof insert in the rear (front is tube because i'm too lazy) -basic ARC30rims
  • 1 0
 with cushcoreXC in my xc bike I'm running 2.3 heavy casing tires at 24 front and 28 rear. With cushcorePro in my big bike I'm running 2.5 heavy casing tires at 26 front and 30-32 rear. Those are the pressures I ran without cush as well but would roll my tires in berms but with the cushcore the rolling has been cured. I dont personally like the low tire pressure feeling for aggressive riding because it feels less predictable. That's just me though. We all ride bikes different and like different things.
  • 3 0
 I’d still dent rims when I ran tannus. Now I just run dh casings and adequate air pressure. Feels better and my rims are protected well enough.
  • 1 0
 About the WeAreOne argument #1 - you say it replaces the progressive air chamber with linear foam, but with that foam also acting like a "token" filling ~half the air volume, wouldn't it in fact be more progressive? My experience definitely feels like that.
  • 6 0
 The volume displaced during a tire compression is a small fraction of the total volume - even with an insert. Also, the insert compresses due to increased pressure, so it's not like the compressible volume is reduced by the full volume of the insert.

As such, the compression ratio is very low, such that the exponential curve of the air spring is insignificant and it behaves nearly linearly. It's not like air springs in shocks and forks, which have a compression ratio orders of magnitude higher.

Even so, the spring rate curves can be complicated. If the tire is being compressed by a large object (ex. a flat surface), the contact patch rapidly expands during the compression, which creates an increasing spring rate, rather than a significant increase in air pressure. If the tire is being compressed by a small object (ex. a sharp rock or a small root), the spring curve is nearly flat without an insert.

The insert creates a second spring curve with a higher rate, a different curve shape, and a different - often complex - cross-section. This produces a two-stage spring and a surprisingly complex set of responses from such simple hardware!
  • 3 0
 @R-M-R: and the beauty of an insert is that it redistributes some of the local (high) pressure of a small area impact across a larger surface, preventing pinches.
  • 2 0
 This is why a new 2.5 dhf exo weighs 1,000 grams. Same thing happened to Schwalbe’s tires recently too. Good for those of us that kill tires but a bummer for the trail riders that never damage stuff.
  • 2 0
 It's true tires have become heavier, but much of it is due to width and the airtight lining needed for tubeless operation.

Many years ago, a Maxxis tire that was nominally 2.5" wide actually measured 2.1". They're still undersized, but far more honest than before - even when mounted on the same rim width. If someone was concerned only about weight and not the other improvement associated with width, tread design, etc., they could use a modern 2.1" EXO that's about the same width and weight as a legacy tire with a tube.

If you don't need much toughness from your tires, Maxxis' 2.6" models are the hidden gems in their catalogue that offer nearly old-school weight with modern width. 120 TPI and thin base rubber make them lighter than the 2.5" or even the 2.4" equivalents. The 2.6" DHF is well under 1000 g and the 2.6" Rekon can be as low as the mid-700s (older versions were slightly lighter for some reason). I use the 2.6" Rekon on the front of my XC race bike and the balance of traction, comfort, and speed is unmatched for this application.
  • 1 0
 Inserts allow lower PSI which results in a softer tire and a softer tire is harder to puncture. Inserts have reduced my punctures from 4 to 5 a year down to like 1 or 2. Softer tire is also going to reduce sidewall cuts, I can't remember the last time I cut a sidewall.
  • 1 0
 Inserts don’t reinforce the casing for rocks cuts, slashes, pokes or other trail hazards. Sure they might keep your rim from damage but I’d hate changing my tires constantly from leaking air through various new holes created each run. I’ve found a rear insert, dh casings both ends, and 28-30 psi is about the only way to keep the repairs at bay on a full day riding park anywhere gnarly, fast, rocky/ledgy. But I’m 200lbs and ouch pretty hard for a blue collar carpenter.
  • 1 0
 What if you're already running 30psi in DH casing tires with an insert and still damage rims?
And would damage even more rims before running inserts.... and the last time experimenting without inserts resulted in a broken rim on the first ride.
Asking for a friend.
  • 1 0
 I was curious about inserts so I bought some and tried them on and off with both my fast rolling and more fun carvy tires. I found that I couldn't really lower my PSI enough to alter the feel or traction. I pinch flatted the hell out of about 4 tires during my tests and I'm not usually hard on tires. In about 6 months, I couldn't find any benefits so I moved on.
  • 1 0
 I had 5 wheel failures (& tire) riding a local slab in 12 months time. I've run Rimpact for over a year now, rear tire only, ZERO failures wheel or tire. Prior to Rimpact, I had to maintain 28 PSI in the rear or I was risking a failure (I'm 165lb). Now I run 25 PSI and gasp....EXO casing front/back.

Rider weight, terrain, tire choice, all play into these comments and "experiential" anecdotes.

Running lower pressures (sub 25psi) for slab riding has immense benefits along with the added protection of an insert - take a poll from the locals in Sedona or Moab where you need the grip on exposure but the protection from brutal square hits as well.
  • 1 0
 Using tire inserts I was always complaining about traction, and don’t knowing why I blamed my self, last year I broke a carbon wheel and my lbs says probably it was because of the tire insert. I take them off and bumped 1/2 bars of pressure, and my problems of traction disappear, gave much more confidence and speed. Soooo, tire inserts, no thanks!
  • 1 0
 Genuine question here: do other off-road sports run inserts in their tires? From my (limited) knowledge MTB seems to be the only sport that uses tire inserts.

I’m not sure what makes off road bicycles moving at ~25mph as a typical maximum would need different tire technology than rally cars or enduro motorcycles?!
  • 1 0
 Enduro motorcycles use foam inserts as a full replacement for air. They're called mousses.
  • 1 0
 Interesting that there's almost no coverage here about Tannus Armour. When we get requests for that, it's not about pinch flats or stability issues, or rim damage--those are all secondary benefits. The driving issue is goathead thorns--a Southern North America scourge--defeating tubeless setups. And we've never had this solution not work.
  • 1 0
 Ride a hard tail in the off-season to improve your skills and learn to ride "lighter". I had Flat Tire Defenders a few years ago, flatted on first ride with them. I hated how hard it was to change tires as well as the added weight. I also found that when you do get a side wall cut the insert kept sealant from getting to the slice. Haven't used them for years now and hardly ever flat unless I really mess up. Ive been riding my hard tail in the off season for a couple years now and its the best cross-training in my opinion.
  • 3 0
 I've never had to walk down the mountain with inserts. It did change the ride and took a bit to get used to but they'll stay in my Enduro bike.
  • 2 0
 Conti used to make tires with more padding at the bead, special color to highlight the feature. I forgot what it was called.
  • 3 0
 Many companies now have various designs to stiffen, toughen, and/or cushion the sidewall adjacent to the bead. Old-school casing construction uses two or four layers in the sidewalls and three under the tread. Tire manufacturers are finally creating much more sophisticated casings.

For example, look at how Schwalbe's casing line-up progressively adds more material near the rim:
www.pinkbike.com/news/schwalbe-announces-5-new-tire-casings-and-2-new-tread-patterns.html
  • 3 0
 If anyone can fit a Rimpack/Spesh Cannibal combo on a Hope fortus rim I’ll eat my broken levers
  • 4 1
 Hold my beer
  • 2 0
 @rimpactmtb: I’ve managed with other tyres but the cannibal done me
  • 1 1
 I run Cushcore XC on my ebike and RockStop on the rear of my 2 hardtails. Been using inserts since 2019 and haven’t suffered a pinch flat in all that time. No idea if they make such a huge difference when using double down tyres, but it’s too expensive to go without and end having to pay for replacements.
  • 3 2
 I don't even think of going riding if the bike doesn't have inserts. Theres alot of reasons but mainly the bike rides nicer and flats aren't anything to worry about anymore. Mynesweepers is definately my fav for years now.
  • 1 0
 I think an easy summary is this; if you prioritize DH riding more than XC or up hill riding.. inserts make a heck of a lot of sense. If the opposite.. it makes a heck of a lot of sense to go without them.
  • 1 1
 It looks to me that inserts are a great example of how things go strange sometimes in mtb industry. We have Dh tires for years , then it was too heavy for enduro , we designed lighter carcasses , but it happens to pinch easier , then we put inserts inside , which is heavy and more expensive than a rim itself. Just go with dt Swiss 511/471, dh casing at the rear. You are good to go for years
  • 1 1
 Funny how Cushcore and Rimpact think their foam doesn't contribute to rim failures when all the rim manufacturers know it does. IMO Cushcore Pro is the worst for this, I've flat spotted a DT EX 511 and didn't even remember how it happened. A friend was seriously injured by a failed DT rim running CC Pro. The truth is the truth. These inserts that sit directly on the rim bed redirect forces onto the rim bed in a way the rim wasn't designed for. End of story.
  • 3 1
 I prefer the MOAR AIR product that some blessed PB commenter turned me on to years ago.
  • 3 0
 Rear wheel only, just to save rear rims. That's it.
  • 2 1
 Tried inserts,not for me,bought heavier tyres with stronger sidewalls,upped the pressure a bit and all good,I would not go back to inserts.
  • 2 0
 Thankful for inserts. They let me be a hooligan and not think twice about going for that gap and having fun.
  • 3 0
 DT Swiss: There are rules!
The Market: We don't need no stinking rules!
  • 2 0
 Ride what makes you confident and comfortable. Also, it always helps when you have a Lifetime Warranty, crashes included Smile
  • 4 0
 This is a great article.
  • 1 0
 I don’t understand why people buy expensive wheels and inserts. All wheels feel the exact same to me when running inserts lol.
  • 2 0
 A lot of talk about burping air and punctures... but all I care about is saving my rims !!!
  • 3 1
 Give me a heavy casing over a pain in the a** insert anyday.
  • 2 0
 That's a veiny, triumphant..... forearm
  • 1 0
 Schwalbe is notoriously shitty to put on a wheel especially with an insert. Their statement just baffles me!
  • 1 0
 Did anyone find any useful information buried within the marketing departments word soup responses
  • 1 0
 Main takeaway from this article is: If we don’t make it, you don’t need it.
  • 4 4
 if you want to make your suspension work like garbage, run and heavy wheel tire and cushcore Smile
  • 1 0
 Inserts in aluminum wheels nothing in carbon wheelsets
  • 1 0
 Another super long advertorial.
  • 1 0
 first badge of FR541: complete garbage
  • 1 0
 Burning Question: Who benefits from broken rims and tires?
  • 1 2
 My burning question is currently coming out of my pee hole, it’s who has my girlfriend been porking
  • 1 1
 Just add more air! I mean that's not wrong, but also a little obtuse.
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