Burning Question: Why Do Some Bikes Have More Travel Up Front?
Not all bikes are created equal, and we're not just talking about manufacturer procedures or quality either. The majority of bikes, especially trail and enduro bikes, tend to have more front travel than at the rear wheel. But, why is that? Well, riding styles and trail conditions play into optimizing the setup for a particular bike segment. You could call this an imbalance, but that's not how everyone sees it. There are different theories out there as to why that works best for the bike's intentions. There are even various ways to measure the amount of travel, as Seb Stott found out when testing the Forbidden Dreadnought.
Other manufacturers choose a different approach where balance doesn't necessarily mean equal travel. A great example that sparked this Burning Question was Yeti Cycles' new SB160 enduro bike with 160mm of rear wheel travel. That's 10mm more rear wheel travel than its predecessor, the SB150, which has, you guessed it, 150mm of travel out back. However, both bikes use a 170mm fork. It's not as simple as just boosting the amount of squish from the rear shock. Yeti references vertical fork travel when discussing the balance between two wheels, which also depends on head angle. So if it's all about how the bike works as a system and not just the amounts of travel, where do you start?
Since there is no written rule as to why the numbers should or shouldn't be the same, we reached out to product managers and tech heads at various brands to pick their brains to ask what determines the front and rear wheel travel for the brand's bikes and how they arrive at those figures.
Colin Ryan - Senior Development Engineer, Norco Bicycles
How does the product team decide on how much front and rear wheel travel a bike will have for the targeted category?
Suspension travel numbers generally come from us thinking about the balance between compliance and support we want to achieve from the suspension on our bikes to suit a specific intended use. Compliance being how the suspension isolates the rider from the trail and support being how the suspension responds to rider inputs that are used to give direction to the bike.
Suspension travel isn't the only factor that affects this balance of compliance and support but it's definitely an important one. Less travel will tend to shift this balance towards the supportive end of the spectrum for applications like XC where the terrain is less rough and riders prioritize efficiency and a responsive ride feel. DH is at the opposite end of the spectrum where more suspension travel allows us to better isolate the rider from the higher speed impacts and rougher trails while still maintaining a level of support that makes the bike feel responsive. These are examples at extreme ends of the suspension travel spectrum but we apply the same line of thinking to all of our full suspension bikes.
Is the bike's purpose governed by the fork travel or the frame's suspension design (travel and characteristics)?
The intended use of each model in our lineup isn't necessarily governed by any one thing like fork travel. From a suspension perspective it comes back to that balance of compliance and support that we want to achieve to suit a specific application. That guides how much suspension travel we feel is appropriate front and rear. This also guides us in selecting a rear suspension layout and defining kinematics for each bike. Of course, there are other important factors outside of suspension like geometry, fit, and bike setup that we consider when designing a bike for a specific intended use. All of these factors combined are what make up our Ride Aligned Design System.
Why might less rear-wheel travel be desired?
Applications like XC where efficiency and a responsive ride feel are prioritized will always tend towards shorter travel overall. But in some cases there is a rider preference aspect where some riders prefer the more responsive characteristics of shorter travel bikes or just enjoy riding closer to the limit of what their bike is capable of. We see that even within our own Product Development team where we're often riding the same trails but choose different bikes based on our individual preferences.
Rear wheel travel is typically measured perpendicular from the ground, and fork travel is measured by the length that the stanchion slides. That makes sense from a fork sales perspective since the bike's head tube angle dictates the vertical front wheel travel. Do you take geometry or the type of rear suspension design into account when pairing a fork of "x" length with the rear wheel travel? For example, some short-travel high-pivot bikes have up to 20mm less rear wheel travel than the fork, but on the trail, that can feel more equal than what the numbers state.
One of our key suspension performance goals is achieving a balance in suspension feel front to rear that allows the rider to maintain a stable and centered position on the bike. Achieving this balance is influenced by suspension travel of the front wheel relative to rear wheel along with a number of other factors like kinematics, fit, suspension setup. We factor in how the head angle impacts the actual vertical wheel travel of the front wheel and consider this along with other factors to determine the appropriate amount of rear wheel travel to achieve the balance we're looking for.
This balance can differ between bike categories, such as a trail bike that might have 150mm and 140mm of travel front and rear, versus downhill or freeride bikes that typically have equal numbers (200mm front and rear wheel travel). Can you comment on why longer-travel bikes are commonly found to have equal front and rear wheel travel?
From suspension test data we've collected on a variety of different bikes we typically see riders running a higher dynamic front ride height vs. the rear. This is to keep the rider’s weight from being shifted too far forward on steep grades and generally to provide the rider with some protection from the feeling of getting pitched over the front wheel. We've learned through testing with our Norco Factory Team athletes that riders generally prefer a more pronounced difference in front/rear ride heights in DH and Enduro racing compared to other applications. As a result for DH and Enduro we design around some additional vertical rear wheel travel to account for this more pronounced difference in front/rear ride heights.
Ryan Thornburry - Product Manager, Yeti Cycles
How does the product team decide on how much front and rear wheel travel a bike will have for the targeted category?
The starting place is typically the intended use of the bike but there is no hard and fast rule. When starting the development process for a new model we will start by riding as many bikes as we can to try to mimic some of the updates we are trying to explore. Sometimes we can validate our theories and sometimes we need to tweak some of our original assumptions. Our lunch ride bikes were born from the fact that all of the Yeti employees were taking the spec’d bike how it was designed and bumping up the front travel to push the bikes even harder. We test all our bikes to 20mm over the spec’d axle to crown measurement to ensure our customers can tweak the fork travel to suit how they prefer to ride.
Is the bike's purpose governed by the fork travel or the frame's suspension design (travel and characteristics)?
I don’t know if you can separate these two variables and say that only one of them defines the bike's purpose. The final product is a sum of all of its parts. The front and rear travel, linkage, geometry and spec are all working in concert. You can drastically change the personality of a bike by changing any one of these variables. With our new SB140 29er, we have two different builds on the same frame. The standard build is more trail oriented and the Lunch Ride beefs the kit up with bigger brakes and tires, longer fork and a piggyback shock to handle more aggressive riding.
Why might less rear-wheel travel be desired?
Shorter travel generally yields a lighter frame with quick and precise handling, efficiency when climbing, and increased trail feedback with less of a get out of jail free card during the inevitable whoops when descending. These characteristics can be ideal across a large spectrum of rider styles. An XC focused rider will certainly appreciate these qualities that less travel would offer for obvious reasons. A highly skilled gravity focused rider may appreciate this handling, even on difficult terrain. The “under biked” feel can make easier terrain more fun, and give new ways to approach challenging terrain while finding the limits of the bike and being on point. A general novice will not likely be pushing the limits of the bike, but will appreciate these qualities during their riding experience without being burdened by being “over-biked”.
Rear wheel travel is typically measured perpendicular from the ground, and fork travel is measured by the length that the stanchion slides. That makes sense from a fork sales perspective since the bike's head tube angle dictates the vertical front wheel travel. Do you take geometry or the type of rear suspension design into account when pairing a fork of "x" length with the rear wheel travel? For example, some short-travel high-pivot bikes have up to 20mm less rear wheel travel than the fork, but on the trail, that can feel more equal than what the numbers state.
Geometry is a major factor when determining the fork length of a frame. What we try to do is balance the vertical travel of our bikes so that when you do the math and look at the vertical fork travel and not actual fork travel, you have a balanced vertical travel number on both the front and rear. Steep headtube angles require less over forking (~10mm) and the slacker your headtube angle is the more over forking would be required (~20mm) to balance the vertical travels. If you want to find the vertical fork travel of your bike use this equation plugging in your bikes fork travel in mm and the head tube angle in degrees: vertical fork travel = for air spring length * sin(head tube angle).
This balance can differ between bike categories, such as a trail bike that might have 150mm and 140mm of travel front and rear, versus downhill or freeride bikes that typically have equal numbers (200mm front and rear wheel travel). Can you comment on why longer-travel bikes are commonly found to have equal front and rear wheel travel?
In “shorter” travel bikes there is more opportunity to mismatch rear/front travel since various fork travel options are available (i.e. greater and less than rear travel). As rear travel increases fork travels reach their maximum so there is less opportunity to explore this mismatch.
Cy Turner - Founder and Director, Cotic Bikes
How does the product team decide on how much front and rear wheel travel a bike will have for the targeted category?
It's actually the other way around for us. Customers very definitely still shop based on the travel a bike has, so we look at the category we want to aim the bike at, what kind of travel the competitors have, and then pitch the best Cotic style product we can into that space.
A good example of this is when we slotted the Jeht into the range. It's a 150/140 trail bike, with slightly steeper, shorter geometry than the RocketMAX enduro bike, but not a great deal slacker (around 0.5deg head angle) than the FlareMAX 125mm travel frame when that frame has 140 forks fitted.
So, we split the difference between the two models (especially as the RocketMAX got longer travel) and the Jeht was born, and it's been a big hit. Customers understand what it is completely, and if they like the Cotic way of doing things then it's the bike for them. Conversely, it's also given us the space to market the FlareMAX a little harder into the shorter travel end of things, to the point where the vast majority of those bikes now go out with much lighter tyres and 120mm SIDs on them.
Is the bike's purpose governed by the fork travel or the frame's suspension design (travel and characteristics)?
Up to a point it's defined by fork travel, because a frame has to be heavier and stiffer to pass all the durability and safety tests the longer a fork gets. And in our experience, the fork travel a frame is capable of is directly proportional to the dumb shit riders will try to pull off on that bike! So, you have to build that into the durability piece. Ultimately though, the bikes' purpose is defined by its travel, and a customer won't accept that your 140 bike is for enduro when everyone else's enduro bike is 160 or 170. Doesn't matter how competent it is or what suspension voodoo you've brewed.
I don't think suspension design comes into it that much in a broad sense. Obviously there's detail differences in terms of optimizing a particular frame to a particular shock stroke, or type of shock (coil and/or air), but we don't change the anti-squat or pedaling characteristics across our bikes that much. With really long travel stuff for DH, I can see things like high pivot idlers being attractive where pure downhill performance is everything, but for bikes you have to pedal up again, stick with a pedal you like (and try not to be a dick about it).
Why might less rear-wheel travel be desired?
It's a good point you make, because with a really slack head angle like the RocketMAX (63.5), the 170mm fork actually only gives 152mm vertical front travel, but it's self evident to anyone who rides that the vertical travel isn't the only story, because you hit bumps head on, not dropped vertically from the sky so you are getting a good proportion of 170mm of bump eating capability. The truth on the trail is somewhere in the middle. The other thing is that your legs are considerably better shock absorbers than your arms (hence why hardtails are able to be ridden at pretty good speed), so your rear suspension also has that in its favor too.
The missing link in just talking about travel is rear suspension design, specifically the rate curve. In my experience, the key to a balanced ride is a balanced suspension setup and feel. The front works harmoniously with the rear. Assuming you're not trying to ride a bike with 90mm rear and 170mm front, if the suspension designer has done their job well, and if the rear is within 10-20mm of the front you should be able to get both ends feeling balanced and that's where you'll get good confidence in the bike.
Our Droplink rear suspension is fairly vertical in terms of axle path, but again, we are somewhat driven by the market. The Gen3 RocketMAX was bumped from a 150/160 bike to 160/160. Immediately people asked if they could put a 170 fork on it (they couldn't because we hadn't designed and approved it for that). Now the Gen4 bike is out which is 160/170, it's definitely an easier, better selling bike because it hits the market. Yet I never felt the 160/160 bike was particularly unbalanced. The main reason we went to 160mm on the Gen3 was to fit Metric standard shocks, so the shocks were arguably better as a result, but the fork never felt overfaced. On the other end of the spectrum, as I mentioned above, the FlareMAX is now really popular with a 120mm SID despite having 125mm rear travel, but it just feels really good.
Rear wheel travel is typically measured perpendicular from the ground, and fork travel is measured by the length that the stanchion slides. That makes sense from a fork sales perspective since the bike's head tube angle dictates the vertical front wheel travel. Do you take geometry or the type of rear suspension design into account when pairing a fork of "x" length with the rear wheel travel? For example, some short-travel high-pivot bikes have up to 20mm less rear wheel travel than the fork, but on the trail, that can feel more equal than what the numbers state.
I've talked enough about balance above, and we don't make a bike in the downhill/park bike space, so there's an element of hand waving here. My best guess is that at the DH end of the market, forks are 200mm travel and that's that. No one is doing anything longer. And given you want to go as fast as possible and generate as much grip as possible, and you're not really travel limited at the rear, build as much travel at the back as you can whilst still being able to get a good setup on it. I also suspect that the uptake of 27.5 rear wheels in DH will see rear travel maybe bump up a little more again as they try to compensate for the lost bump rollover of the 29 rear wheel. There's already a couple of bikes out there with 210mm rear travel, and as you mentioned above, the rearward axle path bikes amplify the travel available, but they're all still 200mm-ish.
Josh Kissner - Director of Product, Santa Cruz Bicycles
How does the product team decide on how much front and rear wheel travel a bike will have for the targeted category?
We decide these things based on experience and preference; that's pretty much it.
Is the bike's purpose governed by the fork travel or the frame's suspension design (travel and characteristics)?
It's obviously both, but I'd give more weight to the rear travel when categorizing a bike.
Why might less rear-wheel travel be desired?
If you're looking for quicker/more playful handling, or something that climbs and traverses terrain better- shorter travel frames will certainly provide a different feel than a long travel bike. Sometimes a longer fork can add to the capability of a shorter travel bike without taking away much of that ride-feel. It's not about weight, but handling differences.
Rear wheel travel is typically measured perpendicular from the ground, and fork travel is measured by the length that the stanchion slides. That makes sense from a fork sales perspective since the bike's head tube angle dictates the vertical front wheel travel. Do you take geometry or the type of rear suspension design into account when pairing a fork of "x" length with the rear wheel travel? For example, some short-travel high-pivot bikes have up to 20mm less rear wheel travel than the fork, but on the trail, that can feel more equal than what the numbers state.
Not really. We've ridden prototypes before where it felt like we needed to adjust from our planned fork travel, but in general we've been happy with something between 0 and 10mm longer fork vs rear travel.
This balance can differ between bike categories, such as a trail bike that might have 150mm and 140mm of travel front and rear, versus downhill or freeride bikes that typically have equal numbers (200mm front and rear wheel travel). Can you comment on why longer-travel bikes are commonly found to have equal front and rear wheel travel?
We have some bikes with equal front and rear wheel travel at both ends of the spectrum, like our Blur (100/100) and Nomad (170/170). In-between, we do a 5-10mm differential between front and rear. We're pretty into balanced-feeling bikes, and haven't gotten into the 140/160 or 125/150 types of travel differentials in any models. While adding a long fork to a short bike can add a bit of confidence that wasn't there before, we would rather have a balanced bike (maybe that's from adding rear travel) than the mismatch. My least favorite feeling on a bike is being pitched forward in bumps, which can happen when you have a firmer rear end than fork. We try to avoid this phenomenon as much as possible. Riders can always put a longer fork on if they want, which can help change the bike's weight balance after the fact.
Jack Doherty - Design Engineer, Specialized Bicycles
How does the product team decide on how much front and rear wheel travel a bike will have for the targeted category?
Travel is just part of the equation when starting a bike project. Our team takes the approach of looking at the rider needs for a given category and builds the bike from there. The goals for the bike and how those needs are best served influence the travel. Frame layout, kinematics, packaging, shock fitment, and more all weigh on this decision. There are general boundaries of course, but our team targets ride characteristics first and foremost.
Is the bike's purpose governed by the fork travel or the frame's suspension design (travel and characteristics)?
Both have an influence. No single variable will govern a bike's purpose but as a frame manufacturer has control over the chassis so there is an increase in focus here for us. Our team starts with the rider's needs and builds the frame and suspension design to the category and experience, not necessarily around a specific fork. On the fork side our given geometry (head tube angle) is the main driver we can directly control that affects how an off the shelf fork will perform. On the rear suspension side we have many more levers to pull- how the kinematic works with the shock tune our team develops, chassis stiffness, and geometry all play a part here.
Why might less rear-wheel travel be desired?
Less rear-wheel travel means that a stiffer spring (or more air pressure) is used to achieve the bike’s sag target and bottom-out force and energy requirements. Stiffer springs move less, so situations where we want more efficient suspension movement can be better on shorter travel bikes. Pumping and pedalling are two scenarios where this is desirable, but it can also be better to have a more consistent dynamic geometry in a wide range of downhill scenarios. Springs are not the only thing that contributes to suspension movement and we tune the damping, anti-rise, anti-squat, and leverage ratio all in an effort to get the best balance of having suspension movement when needed and to prevent it when we don’t.
Rear wheel travel is typically measured perpendicular from the ground, and fork travel is measured by the length that the stanchion slides. That makes sense from a fork sales perspective since the bike's head tube angle dictates the vertical front wheel travel. Do you take geometry or the type of rear suspension design into account when pairing a fork of "x" length with the rear wheel travel? For example, some short-travel high-pivot bikes have up to 20mm less rear wheel travel than the fork, but on the trail, that can feel more equal than what the numbers state.
Our team does take the geometry of the bike and the suspension kinematics into account when pairing a fork with a bike. When we are tuning a bike’s kinematic design and shock tunes using data collection, both the front and rear travel numbers are converted to vertical travel so a better picture of how the suspension is working together can be seen. This is why some bikes have more travel in the front than the rear so that the vertical travel numbers are more similar
This balance can differ between bike categories, such as a trail bike that might have 150mm and 140mm of travel front and rear, versus downhill or freeride bikes that typically have equal numbers (200mm front and rear wheel travel). Can you comment on why longer-travel bikes are commonly found to have equal front and rear wheel travel?
We tune the ratio of front-to-rear travel to achieve desired ride qualities. There are many factors that determine a bike’s dynamic geometry numbers and the amount of both vertical and horizontal travel are a major factor here. On longer travel bikes, having equal travel numbers ends up resulting in more vertical travel in the rear than the front. This gives us a dynamic geometry that gets slacker as the bike moves through its travel resulting in a more stable platform. On shorter travel bikes, there are more ride quality traits to balance which means that equal vertical wheel travel (longer travel fork than rear travel) ends up giving a more consistent dynamic geometry that better balances a bike’s performance in a wider range of trail situations.
Felix Weber - RAAW Bikes
How does the product team decide on how much front and rear wheel travel a bike will have for the targeted category?
Some bike categories, like XC and DH, do have a more defined travel range to be within. But in between those two extremes, the travel range limits for down country, trail and enduro are a little fuzzier. That’s why it’s not solely the travel amount that defines a bike, but a lot more factors.
Most of the factors that we throw into the mixing bowl, along with amount of travel, are a little more ambiguous. Like, how do we want the bike to feel? What should it be capable of handling? When should its limits be felt? And when approaching them, how much of a white flag should it wave or should the bike ask for a bit of backup?
Our Jibb could have had more travel out back and up front and still been in the trail bike category. But when we thought about a little sibling to the Madonna, we wanted to capture a certain ride characteristic, a certain feel. It’s hard to express something like that in just a couple of numbers.
Other factors are more objective, like clearances of wheels, tyres, shocks, frame parts colliding, and the desired geometry of the bike. That last one ties back into the more subjective aims of the bike above.
It’s probably worth mentioning that we don’t sit down for a meeting just to define a travel number and set it in stone. It’s something that can evolve as the bike development does. All the various factors
that go into development are very intertwined and considered all the way through, together. Putting together a concise answer to the question of how we decide on the amount of travel is hard. It’s not
as simple as travel, tick, and onto the next thing.
Is the bike's purpose governed by the fork travel or the frame's suspension design (travel and characteristics)?
Both of those things, and much more.
They’re two parts in a list that we honestly have never stopped and counted how many factors are on it. Maybe we should, but it would be scary. With bikes the way they currently are, fork travel on its own can be altered by a rider within some pretty big ranges. Long forking is fun, but there’s always a point at which you start to throw the bike all out of balance and have detrimental effects to the geometry and strength of the frame. Suspension designs are fixed. Once you have a bike with a certain design, you can’t swap it or add more links. Each suspension design does have its own inherent characteristics, but again, that’s only a few select pieces of the bigger puzzle. Complicated question, complicated answer.
Why might less rear-wheel travel be desired?
In the same way that a less aggressive tyre or smaller wheel out back might be desirable. The front of the bike is the first point of contact for the bike encountering the trail and generally points the bike in the way that you want it to go. Having that end under gunned narrows the window for error and makes it harder to ride hard. If there’s confidence, stability and capability in the front, then riders can more easily get away with wildness happening at the rear of the bike, as the rest of the bike can often drag it out of problems with its momentum.
For more vertical rear wheel paths, more travel up front can give more balance in having similar vertical wheel travels with the slack head angles that have found their way onto even short rear travel bikes.
Maybe it’s also something desirable for shorter people with less trouser clearance. But smaller rear wheels have helped a lot here. More travel with a smaller rear wheel is nicer than less travel with a bigger rear wheel.
Rear wheel travel is typically measured perpendicular from the ground, and fork travel is measured by the length that the stanchion slides. That makes sense from a fork sales perspective since the bike's head tube angle dictates the vertical front wheel travel. Do you take geometry or the type of rear suspension design into account when pairing a fork of "x" length with the rear wheel travel? For example, some short-travel high-pivot bikes have up to 20mm less rear wheel travel than the fork, but on the trail, that can feel more equal than what the numbers state.
Absolutely. It comes back to the need to look at all the factors at the same time when developing. When you’ve got it all drawn out in CAD, it’s easy to see how much vertical travel a fork will have, or how much travel along the axle path the rear suspension has, or how that axle path is generally inclined.
More travel up front on a bike is common, especially in that space between XC and DH. It’s nice to have more party up front, and it aligns with having some balance in the amount of travel perpendicular to the ground. But focussing on just the amount of vertical travel in the fork can lead to forgetting the overall balancing act that might include things
This balance can differ between bike categories, such as a trail bike that might have 150mm and 140mm of travel front and rear, versus downhill or freeride bikes that typically have equal numbers (200mm front and rear wheel travel). Can you comment on why longer-travel bikes are commonly found to have equal front and rear wheel travel?
DH bikes have been through a long tried and tested process. Sure, they’re evolved. But perhaps not to the degree of trail and enduro bikes. Lots more than 200mm has been played with a lot in the past. But the added wheel movement (frame clearances), chassis movement and ability to suck the energy out of rider’s inputs are just a few reasons why there’s been a plateau in their travel.
No doubt it’ll be explored again at some point, as the cyclical recycling of ideas happens. But it’s generally been pretty stable for the past decade plus. It was one of the first questions I asked brands
when I was doing research for my thesis at university, designing a DH bike. And that was now twelve years ago.
As you approach that amount of travel, you’ll get closer and closer to the reasons why around 200mm travel has become the upper limit. You’ll introduce more and more of the flavor of those down sides.
But there’s still a lot of room for over forking in long travel non-DH bikes. 170mm out back and 190mm or 200mm up front are still viewed as just fine, with the context of terrain, rider and what you want the bike to do.
When you have less travel out back, like the 140mm or 150mm mentioned in the question, there’s still a lot of room to change the fork travel, within the limits of what we talked about before. But then the balance of the bike from front to back can become a bit out of whack. 180mm travel on a 120mm travel XC bike might make it rider more like a stapler than anything else. It’s all about balance in bikes.
199 Comments
But the discussion about head angle changing when going through the travel is a weird one. Just because the fork sucks up a bump doesn't just suddenly imply the head angle got a whole lot steeper. I'd argue the head angle should be measured with respect to the velocity vector. If you're still riding a horizontal path, the head angle should be considered constant even when the fork compresses to absorb an obstacle. By this logic however I do agree that when I do absorb a hit with my legs (hence the bike tilts forwards) the head angle does indeed steepen a little. Either way, I don't know whether this should be considered that much of an issue. This is mountainbiking. You'd expect irregularities on your trail to be much much bigger than those 150mm or something suspension you have. Watch DH or enduro racers tackle a rough section, the bike is also constantly pitching up and down. That's called bike-body separation and you're going to do that whether you have rear suspension or not.
My hardtail has a 120mm travel fork and a 63deg (unsprung) head angle. @matyk, it should be crap by your reasoning but I think it works perfectly fine. I'd hate it to be 66deg or steeper.
A long travel fork is not a good match with traditional steeper head angles because of how much more it’ll steepen when you’re pointing down a steep hill.
I’ve had hardtails with everything from 100mm to 160mm of fork travel, 26”, 27.5” and 29” wheels and 70 to 63 deg (static) head angles. Big fork, big wheels, slack head angle is where it’s at for me!
Legs longer than arms.
rear travel go up and down. Front travel go sideways too, so up and down go less.
Pedaling no affect front suspension.
I also think that rear suspension simply works better than front suspension since its not stanchion based. I'm really curious how the Structure Cycleworks bikes ride, since they have linkages for both. @R-M-R thoughts?
I agree that front traction is more important than rear traction on bikes.
Other factors that may have been mentioned in the article (haven't read it yet, just wanted to reply to you quickly) are that our hands are displaced nearly 1:1 with the front wheel, while our feet aren't as directly linked to either wheel; feet and butts are less delicate than hands; the ability to "hop and pop" is more closely related to leg inputs than arm inputs.
Among the many things I like about front linkages is the increased ability to control dynamic geometry throughout the travel. For example, the geometry can be "XC / Trail" in the early part of the travel, and transition to "DH" by the end of the travel. We've become accustomed to the way telescoping forks affect our dynamic geometry, so a front linkage with completely different properties feels foreign, at first, but it's important to not dismiss different as worse. If we started riding on a linkage fork with certain characteristics - they're not all as much alike as telescoping forks - and spent years or decades riding similar designs, telescoping forks would also feel foreign ... and I don't think it would be in a good way. The loss of front-centre length under forward pitch on a telescoping fork is such a terrible property for handling.
We all say things like 'balanced front to rear', but that bike actually feels like what that truly means.
Very cool bikes.
When you say understeer is better than oversteer you’re trying to be funny, right?
Understeer might be considered “safer” (non-sense), but only for those that don’t have some car control skill. Understeer certainly isn’t better in anyway, shape or form.
Understeer is only correctable by slowing enough until the front tires can handle the opposing forces being placed on them, oversteering, when done even slightly well can help to change direction with both throttle and braking.
If you’re ever up in the Okanagan, SilverStar has a couple for rental you can try for the day.
I’ve been meaning to give one a go for a couple years, but when you head up to go lift accessed riding, it’s real hard to decide to go for a pedal for the day.
Just about learning some skills, similar to braking, shifting, changing lanes
Many of the equipment choices we make are to compensate for our lack of dynamic driving or riding skills - and there's nothing wrong with making such choices, it's just important to understand why specific choices suit specific people in specific situations.
Braking, shifting, and changing lanes certainly arent the minimum, as those are sometimes difficult for some, but im being pedantic, I understand what you mean.
As I said, Understeer, in any situation is not the "better" solution for the problem trying to be solved. Learning and practising car control skills would be the "better" solution, it might not be the easiest to implement, but thats a differnt topic.
Similarily, with bike control skills, learning and practising the correct, or prefered bike control skills is the "better" solution.
I think we make equipment choices for many differnt reasons, and in reality, "most" likely choose things for much more superflous reasons, than making up for lack of skills.
Is purchasing a Fox Factory fork, over a Rthym, done to make up for lack of skils, or for ones vanity?
Is running an XT derailleur making up for a lack of skill, or to show off a bit?
Is running a Deity stem over a $30 chunk of alu for anything other appreciating some blingy bike jewelery?
Outside of maybe tire choice, what items do you think we are purchasing to make up for a lack of dynamic riding skills?
@onawalk: Yes, people make emotional choices that may not align with the highest return on investment for performance. I was thinking in terms of the latter, in which case we might mount a front tire with far more traction than the rear to ensure a "fail safe" loss of traction, slower than ideal rear rebound damping to reduce the risk of getting bucked, longer and/or slacker geometry to compensate for insufficient body movement. A more skilled rider may not need such things and may be able to achieve slightly higher performance without them, while a lesser skilled rider could benefit greatly from a little extra insurance in their set-up. This is probably what @hamncheez was getting at with his car understeer comment: not the highest possible level of performance, but it reduces the chance of novices getting themselves in trouble.
Same concept on a bicycle, a motorcycle, car or a 26’ U-haul truck.
All are controllable ,it just requires learning the skill, and practising it.
Love drifting both bikes and motorcycles
I think it might increase the amount they get into trouble, but potentially decrease the amount of damage to their own vehicle, and others. Assuming we are talking about cars still
The move to produce cars that understeer rather than oversteer was likely pushed, and lobbied for by insurance companies, in an effort to reduce costs, etc.
If we are talking about outright performance, then an equal amount of traction on both wheels might (confining and scenario dependant) be the fastest way around a corner. But I’m willing to go out on a limb, and say very few are actually looking for the fastest way around a given corner.
The comment about a more skilled rider not needing said thing to achieve slightly higher performance is fairly general. If a slightly slacker HA u]is a benefit in a given situation, then it’s a benefit. If a higher skilled rider doesn’t need a slacker HA to maintain or achieve a slightly higher level of performance on a given section, then they are reaping the benefits of a steeler HA in other sections. But that doesn’t negate the performance benefit of the slacker HA, it only highlights how all these things are a compromise one way or another.
Or am I out to lunch?
The reason is that you have a lot of crumple zone in front of you, not much beside you, and almost nothing above you, so in combination with the fact that it's relatively easy to roll a car sideways and extremely difficult to do that end-over-end, it's a lot safer to leave the road or hit something traveling basically forwards rather than sideways. It's not better for high-performance handling as such, but for the general population it's safer in the sense that less people die.
I get that understeer is built into cars, along with all the electronic nannys to keep you headed in the right direction.
I understand that it’s done under the guise of keeping people safe,
But in no way would you consider it “better” , it’s just another fail safe to compensate for what I think should be basic road skills by all who pilot 2 tonne mega horsepower vehicles down the road.
Especially here in Canada where we regularly have to drive on very low traction roads. I believe all are capable, just not expected to.
www.nhtsa.gov/sites/nhtsa.gov/files/documents/12980-rn-est_lives_saved_esc_2011-2015_032917_v2_tag_0.pdf
It’s not better, and I’m certainly not alone in thinking that. I think the term youre looking for traction, and slip control, all the ones you noted are simply trade marked names for different electronic versions of the same thing. It’s an easier implemented solution than education, cause it can be implemented at the manufacturer level. It does nothing in vehicles that aren’t equipped, older vehicles, commercial vehicles, or cars that you can simply disable it on.
Not better, easier to implement, at the cost of those that don’t require or want it.
Forcing “safety” just teaches operators to rely on it, and being a mechanical and electronic contrivance, will eventually fail.
Again, easier to implement, at a manufacture level, so then it’s easier to mandate.
Much more difficult to engineer oversteer into a front wheel drive car, as it oversteers by lack of rear grip, rather than power oversteer in a rear wheel drive car.
You get that it’s not “better” right? It’s just the direction that has been taken. Better would be education and driver training, so that people weren’t reliant on an electronic driver aid.
Mass adoption of something is based on much more than what’s “better”
Data showing anything is heavily skewed towards what the author wants to present, you took a high school statistics course I imagine. Traffic stats, like all stats, are collected, categorized, and presented in a way to justify the laws that are put in place.
in Canada, if you’re doing 15kph over the speed limit, and someone pulls out in front of you, and you hit them, that the cause of that accident can be attributed to speeding. That’s a pretty far stretch in my book. Willing to bet it’s the same in the US.
Understeer, once it’s started, can only be corrected by slowing the vehicle enough for the front wheels to regain traction (which becomes increasingly difficult when you’re asking the front wheels to steer, brake, and provide power) Oversteer, can be controlled, and be brought back into complete control by means of slowing, and the addition of power and counter steering. So on low friction surfaces (ice, snow, wet) oversteer, can be controlled if the driver has fairly rudimentary skill and practice. You’re gods curling stone when you’re understeering towards a snow bank.
Is an understeer tendency better as an end product if safety is your first priority though? Unquestionably yes (and fair enough if safety isn't your first priority when choosing a vehicle for handling, but you're in the minority if so). There are people out there with 50+ years driving experience who, pragmatically, we just are not going to be able to retrain to deal with a car sliding. And even if we did manage that, it's worth pointing out that despite having more degrees of control over oversteer, in slippery conditions it's extremely easy to loop out and have a (much more dangerous) crash where you hit something side-on or roll the car, especially given that most vehicles with automatic transmissions have a massive lag between the pedal and the wheel. Yeah, there are situations where understeer can cause a crash that a neutral or oversteering vehicle might have been able to avoid IF the driver was highly skilled, but there's unquestionably a far greater number of times that understeer prevented lethal rollover or side intrusion than the number of lethal crashes caused by the understeer itself.
Education and training are great but by the time anyone managed to get any significant percentage of the population trained in how to handle an oversteering car consistently and safely on icy surfaces, we'd all be in self-driving cars anyway. Training isn't actually a statistically viable proposition as an alternative to just building a car that's harder for the average person to kill themselves in.
Front wheel drive cars exist partly due to cost, packaging, and occupant comfort/space. They aren’t inherently better than a rear wheel drive car. Any safety benefits is simply marketing to sell a product.
Willing to bet, people with 50+ Years of driving experience grew up, learned to drive, and quite comfortably drive rear wheel drive cars, much like myself.
This is a fairly pointless argument, it’s opinion based. I’ll concede that current vehicles are safer with understeer, and as I said earlier developing cars in such a way was the easier path than driver training. I’ll never agree that understeer is better, which is what @hamncheez stated.
You’re frustrated by my comments, and that’s fine, but you at any point can also just stop commenting.
As said, I’ll concede current cars are “safer” with designed understeer, but that’s a side effect of taking a path of least resistance in terms of manufacture, and governance. Safer does not mean better, and I won’t agree that understeer in any form is better.
I want my front wheels to grip, at all times, and for the rear of my motorcycle, or bike, or car, or truck to be loose, so that I can control it with either the application of more power, or less power.
Drifting is not a terribly hard skill to attain, especially when you drive on low friction surfaces for 6 months of the year. There’s no magic in it, especially if you’re not doing it for points, or in a “race”.
If you’re ever in the area, swing by, I’ll show you just how easy it is.
Remember how American cop cars were almost universally Crown Vics back in the day? They were RWD, and chosen because they could accelerate faster than a FWD configuration. However, after a decade of experience with them, police departments switched to the Impala (and others) because the increase in acceleration from RWD came with increased instability, and too many cops would lose control when flooring it. A FWD vehicle is inherently much more stable than a RWD. This can be corrected now with electronic stability control, but now cop cars are generally AWD.
Cops require lots of training for driving. I'm not sure of the precise figure, and it varies, but around here its 20 hours+ annually. If trained cops, who drive vehicles that are fleet maintained with high performance tires that are changed out long before reaching the wear bars STILL benefit from electronic stability control, what does that say about the general population?
If I'm not misinterpreting, I think we all agree the highest possible performance - whether bike or car - will come from a vehicle with more balanced and agile handling. Such a vehicle has a higher upper limit for a skilled operator, but can get a novice into more trouble by failing in ways that are less intrinsically safe.
The point of contention, if I interpret the conversation correctly, is the expectations placed on the operators. @onawalk appears to be saying "it's a better car, so just require them to learn how to drive it and the results could be greater safety via higher performance", while a few of us are saying "that would be ideal, but people aren't going to change their behaviours and learn the necessary skills, so we need to provide intrinsically safe equipment; even if reaching the failure state is more likely, the failure mode is safer".
You're both right! Unfortunately, only the latter reflects the true state of things. A small fraction of the population will put in the time and effort to build their skillset; for everyone else, there's understeer and electronic wizardry.
Also worth considering that for most drivers who never (deliberately) approach the limits of grip, under/oversteer has zero bearing on how well they feel the car handles, because until one axle or the other is significantly slipping, there is no under/oversteer anyway. If you want to go for a moderately spirited drive (you know, the average moderately wealthy 50yr old in a "sports" car that's just a family car with a spoiler on it) on a clear sealed road, it doesn't actually have any relevance because the wheels are gripping not slipping (yes, they're always technically slipping, but slip ratio 0.2 or slip angle 5deg means they're effectively gripping). If you're racing (or pretending to), it's an entirely different story, understeer doesn't do anything good there.
Opinions, similar to a*sholes I guess.
I’ll be the first to admit, @hamncheez and I were arguing semantics. Best, for me, does not necessarily mean safest. It’s exclusive of it, but there you have it.
Cars with inherent understeer exhibit that weight shift dramatically towards the front outside turning wheel well before excessive slip, which does affect the handling before, quite drastically in fact.
Older Audi turbo, which exhibited understeer at a drastic rate, vs E30 BMW 3 series, the 3 series which ghastly a tendency to neutral to oversteer is a much different car, well below the limits of grip.
If you’ve designed understeer into the car, youve designed a car that is inherently stable, but more easily surpasses its limits for grip, add to that front wheel drive cars (I’m including any of the more common AWD which are essentially FWD) and you’ve got a scenario where you’re asking the front tires to do way to much work. So you end up finding those limits of grip much more quickly.
Maybe that’s safer, but it still affects handling in lower speed situations, and you get to the limits of grip quicker, neither of which, as my definition goes, is better.
"In our ongoing efforts to Pedal Our Planet Forward®, we strive to celebrate the diverse travel preferences of our of riders, retailers, and communities. While our S-Works line, and especially our Turbo models, are undeniably the best space for our communities to innovate and grow, we fully support* that the time is now to honor teammates whose travel preferences are as innovative as we are."
*Altering the stock travel on your Specialized bicycle will void your warranty. All maintenance should be performed by an authorized Specialized Retailer.
If you run the quoted SB150 #’s that’s 126mm (f)/105mm (r).
I don’t think overforking to match front/rear vertical travel argument really pans out unless you’re running equal sag f/r which no one does.
Just pointing out that Yeti’s argument about matched vertical wheel travel doesn’t hold a lot of water once you set up static sag.
Spoken by the brand owner who actively encourages the customers to ride dumb shit on their bikes when on rides!
That (plus the legs vs arms thing, and the sliding rear vs sliding front thing) is why I really enjoy riding a hardtail with a 160mm fork.
But I’ve got that same fork travel on my 157mm rear travel full-sus and that works great too - but in a v different way!
Highly recommend watching his videos if you're interested in that stuff.
So are motox riders that much stronger?
On a bike, most of the force compressing the fork comes from your hands. On a moto, most of the force comes from the moto itself.
Thanks, experts.
Typical static sag is around 3% iirc and static sag is around 33% front and rear.
On top of that due to the stroke of the rear and the forks being coil they are more linear in nature than a mtb suspension.
In short: motorcycles are heavy and absorb some of that smash. Your bike is probably heavier than you whereas in mtb your body represents most of the sprung mass on the bike
As a matter of fact, the only way I was able to achieve even suspension usage… was to reduce the fork travel to get it closer to or identical to the rear travel.
That was the question, but it didn’t really get answered.
This ^ is kind of a big deal cuz lots of folks overfork their bikes, we’ve seen hardtails running 160-180 forks, but ya gotta wonder if there’s any benefit.
The “comfort” aspect of suspension takes place in the first 1/3 of the travel, the remaining 2/3 is for significant impacts
, for which we are usually out of the saddle. Riding out of the saddle, our suspension is increased significantly because now we can accommodate movement with our body.
For all the mullet boys, running huge stack, I kinda wonder if the out of balance geo entry they r created will lead to a modified riding position; ie not natural and inefficient.
There are tons of ways to make a great bike, and it doesn't have to look a certain way... Perhaps 100 mm of rear travel and 180 mm of front would make an awesome trail bike. I bet the amazing engineers out there could make it work. For a long time people thought that a 160 mm bike with a 64 degree head tube was stupid. Look at us now....
Shouldn’t each bike, based on geometry, be assessed for the ideal fore-aft travel “balance”?
I think folks have some magic number in their head, function be damned!
“I’ve got a 180/160 enduro bike”
In other words, sin(69°) = 0.93 and sin(62°) = 0.88.
"effective fork travel" it must be added to all geometry charts now!!!
I put a 170mm fork on it. Geo is very similar to stock, the bike is so much fun. It can take big hits but has the poppiness of a hardtail
Keep in mind, 27.5 wheels front and rear. 27.5 Fox 36 at 170mm travel.
Ideally I would have done this to a Spitfire but the Phantom is what I had.
When I bought the 36 it was already set at 170mm travel, so I thought I would give it a try. Feels great, and no need to reduce it to 160mm.
I'm also at 120mm travel in the rear. BB height is around 330mm in High mode. Head angle is 68ish, which is close to stock on the V2 Phantom.
www.youtube.com/watch?v=ej7CRAIGXow
Ummm, no
Why is that incorrect?
Shorter travel bikes ( assuming all other things being equal) will usually weigh less.
XC race bikes rarely weigh more than 25/26lbs. Enduro race bikes rarely weigh less than 30lbs…
Bigger travel brings with it bigger forces and impacts. If you don’t modify your frame design accordingly, the frame will crack and fail.
Bike designers are generally trying to make a frame as light as they can, for its intended use and travel.
The forces on the shock and fork itself, would be less with bigger travel, dimensions, weight, etc.
However, as travel gets longer, the leveraged forced being applied to the frame increases as the wheelbases expand to allow for more travel. That’s why frames usually have a maximum fork length, etc. This is why most frames don’t allow you to run a dual crown fork, it puts too much stress on the head tube.
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