Versus can be such an ugly little word, especially in bike testing. The problem is that it demands absolutes, that the world be divided into black and white, yet as you start to get more of a sense of how a bike could and should work you begin to understand that we are working in shades of grey. So I don't want you to read this story as aluminum versus carbon, and if you are looking for a clear cut answer I can save you some time and tell you right now that I don't find one. Rather, this is a small experiment to test the conventional wisdom and try and figure out what works best with my bike, for me. The hope is that me working through this will get you to think about what components you choose, and why.
A Brief History of StiffnessThis story was worth writing for that sub-heading alone, right? Before we dive much further in here we need to cast a glance back across mountain bike history. What many of you may not realise is that compared to a few short years ago, we are now in a golden age of mountain bike technology. Anyone who rode in the '90s will tell you that the idea that a solid 95%+ of products on the market being structurally up to the task is huge progress. My first riser bar was a Club Roost Go Fast bar (maybe it was called something else, all I remember is that it had "Go Fast" etched into it). The other thing I remember is that it needed a brace across the middle to keep the two sides properly joined together. It is a mark of progress that many of our younger readers probably can't even imagine riding with a wobbly handlebar, but back then we accepted it and told ourselves it looked more moto like that...
The same goes for the rest of the bike; frames and forks flexed, wheels bent, seatposts snapped. I don't think you could pay the modern World Cup racers to take to the slopes with the original 32mm-stanchioned Boxxer. You don't tend to see frames smeared black around the stays where the wheel and frame made contact under load. It was a big engineering challenge, one the industry rose to meet admirably. What this meant is that for much of mountain bike history, stiffer meant better. It was a good mantra. It worked. The problem is that today things are so good that it is no longer true. Unless you are buying inappropriate kit for your riding, you rarely have to consider whether your components will be structurally sound. It is a given that it will be stiff enough and that mantra is now out of date. The problem is that this next step in bicycle evolution isn't as clean cut. "Appropriately stiff" is a much shittier marketing line than "better." It is much harder to talk to consumers about compliance and feel, especially when you have spent the last twenty years telling them that stiffer = better. But I believe that is where we are today and those are the conversations about bikes we need to start having.
My Personal StiffnessDon't get me wrong, I love carbon wheels.
I rode shitty bikes for enough years to love the warm glow of satisfaction in having a bike that is almost all carbon and ridiculously light. Even as a bitter industry cynic, I never get tired of having great bicycles to ride, it is a privilege that I could not afford if I did anything else for a living. I love the menacing deep sections, the zip of acceleration that you only get with a couple of thousand dollars-worth of wheels. So it was only natural that when it came to build my bikes I sought out carbon wheels. For a few years I ran the Ibis 741 then 941 wheels on my bikes and the wide, fat profile and the low weight felt great.
The problem started when I changed bikes. I had been riding an Orbea Occam TR and it felt good. I didn't spend too much time thinking about it, the bike just worked and I had fun. When I replaced the Orbea with my current Scott Spark I started noticing something (I wrote quite a bit about
how I set my Spark up last year). My new Spark was a noticeably stiffer frame, much more direct and pointy than the Orbea, but I was struggling for traction. On off-cambers and hardpack terrain the bike was skittish and I found it hard to hold a line. This lead me to start to think about what I could do to find more traction, I didn't want to play too much with fork setup or tire pressures and casings as I had found a setup that worked for me; I really liked the way the frame felt and the shape of it, which left me looking at the wheels.
TestingTo make the test useful I needed the closest I could find to direct equivalents - wheels where the main difference was only in the material used. This lead me to DT Swiss and their XMC1200 and XM1501 wheels. Both are designed by the same people with the same style of riding in mind, and they share the same hubs, spoke count and inner width (30mm). The XMCs do have slightly fancier spokes, but other than that they are as close to direct equivalents as exists in the market today. One thing I did realise when putting both pairs under close scrutiny was that the weight difference was much smaller than I expected - around 100g per wheel, some of which can be attributed to the lighter Aerolite spokes on the carbon wheels. I will say that on the trail the weight difference did not make a big difference for me.
With both sets of wheels mounted up with my preferred combo of Schwalbe Magic Mary on the front and Rock Razor on the rear, I headed up to Viola St Gree - a little gem of a bike park in Piedmont that boasts a pair of incredible blue trails that would be a lot of fun to session on my Spark.
Before riding I checked the tire pressures to make sure they were at my preferred 23/28psi setup. I then did a couple of laps on each set then switched wheels and carried this pattern over ten laps, using the afternoon laps as my timed tests. It came down to the final two hot laps (on my final lap we stopped to take photos) - the first on carbon, then a final hot lap on the aluminum. Looking back, I can see that my heart rate ran higher on the second run, but I tried to be as consistent as I could in putting down the pedal strokes and I'd put that difference down to getting caught up in a good lap.
On the carbon rims I felt faster where the going was easier, I cannot deny that - there is nothing like the feel of railing a smooth berm on a good carbon rim, there is an incredibly positive feeling of drive that the aluminum could not match. Yet as I got further into the 7 minute-plus run, I was starting to feel a little beaten up, there was quite a lot of chatter being transmitted back to me and when it came to dusty, hardpack off-cambers I was struggling to get the bike to hook up.
The big difference with the aluminum rim was in the smoothness, there was an immediately noticeable difference in the ride, everything felt a little more fluid. While the feeling in the berms was good, it just wasn't that same driving sensation. On the off-camber sections where I was struggling for grip on the carbon rims I was finding it easier to hold my lines, and there was a very definite improvement in overall grip. On the long, five minute second main sector of Ottovolante (
OV Sector 2) I was flying on my final run - that reduced chatter and additional grip makes a big difference when you are a few minutes into a trail, and I felt like I could ride harder for longer. The one caveat here is that on my timing I dropped four seconds to the carbon rim on that sector, however that can be explained away because a rider pulled up in front of me in the middle of the trail metres from the finish. In that instant I may not have been the courteous trail user I like to pride myself on being as I knew I was on for a good time. I felt even more stupid afterwards when the gentleman came over to me in the carpark to ask if I was ok... Still, on the timing sheet I only dropped 4 seconds, despite losing more than ten seconds to that incident. On the
Ottovolante pt1 segment, I came out 19 seconds up compared to my time on the carbon rims - 4:49 vs 5:08 - even with that stop.
ConclusionsIf you're waiting for me to use the word "better" or tell you which one to buy, I'm going to disappoint you here. For me, for where and how I ride, this test has convinced me that I should stick to aluminum rims on this bike. With a stiff frame like my Spark, the reduced fatigue and improved traction of the more compliant rims work - it has eliminated that skittish feeling that started me down this road and put into sharp focus the difference in trail feedback between the two wheelsets. The problem with me reaching this conclusion is that I do not believe it can be generalised - my Orbea was great with carbon rims, maybe your frame will be too. I have a Specialized Stumpjumper Evo in aluminum coming and this has convinced me to go through a similar process for that bike as I'm curious to know if carbon wheels will complement the (in theory) more compliant frame.
This test has lead me to believe that we should be looking at our bikes as systems, not collections of components, but that poses a huge challenge to both consumers and the industry. Unless you are happy to trust that bike companies know what they are doing in terms of overall system feel with their OE specs, how do you go about putting together your bike as a system? And how many of us don't love customising our bikes to make them our own? As a writer for Pinkbike I can phone DT and ask to borrow €3,000 of wheels to test a theory, but how many consumers are in a position to do that? At the moment there is no way to work out what frames and components work in what combinations to give the ideal level of compliance for a given rider, and I don't know how the industry would even start to address that. The other thing I am now certain of is that running down the road of "stiffer is better" is a dead end and the sooner that stops being an oft-repeated line, the better off we will all be.
>There’s this profession called “dentistry...”
Let's also acknowledge the 'fact' that the bike industry (like any other retail entity) is constantly pursuing new tech to push on us. That is, alloy wheels almost certainly suffice for 98% of riders the world round, but dentists and dentist-wannabes have fistfuls of dough to spend.
Give it time and we'll see graphene wheels (and Chinese knockoff graphene) before too long.
Literary reference: Princess and Pea.
(Yes, I'm going for neg props. gimme gimme)
Also tyres matching rims would make a difference be it type and size.
One thing I know, my Slash (full carbon) doesn't beat me up riding it as my old alu Radon Race XC hardtail with DT 1900 alu rims. That thing makes me feel like I have gone 20 rounds with Mike Tyson after a ride. It really sucks - by the way, anyone want a used Radon Race 8.0 2014 model???
But it's really not the case. For some people world cup tech is great. But for the majority of the MTB world it's not appropriate.
I am drawn to one James May who openly states that the Nürburgring has ruined many cars. They develop them to set the fastest times on that track possible so they have that headline figure, but ruin the dynamics for normal drivers, at normal speeds, on normal roads.
To further drone on I can also equate it to Badminton racquets. When I first played badminton I decided to get a Racquet and I wanted a nice one so I spent £50. It was good, it improved my play and I had fun. But N+1 applies to all sports and after payday one month I spent £150 on a racquet because I'm stupid. Did it step my game up by 3 times? 2 times? a little bit? No it made it worse. The sweet spot on the racquet was designed for a professional thus I could not effectively smash and the weight made it twitch rather than stable and methodic...
I digress of course.
Rachel Atherton; today
Me and the Athertons require different levels of performance out of our equipment and I have considerably less skill to use that
And like I say, some people will be able to get the best. But not a lot. It's good that World Cup level bikes are accessible to the common rider. Makes you feel good, and is great for Privateers who, short of suspension support, can really make an impression.
There's a certain youtube review with many years experience and frankly his reviews have become cookie cutter. Always the same things said about the bikes.
It would be nice if there was a group of testers with different styles and tastes that you could acquaint yourself with and then have more faith in their reviews. But then if I spent all day, every day, testing bikes I think my fitness, and skills, would improve to a point where my reviews might become less relevant to the every day rider.
You do occasionally see products and/or bikes get roasted. I've definitely seen a lot of cheap tires roasted on completes (reviewers changed them out straight away because they're trash), outdated geometry normally gets called out, bad saddles and grips, suspension that isn't up to par etc.
Most medium-high end bikes tend to get similar comments because they're basically all pretty good and often all pretty similar. I can't think of many bikes from the mainstream companies that are genuinely, objectively bad. Bike companies know how to make something that is going to behave pretty well. A lot of companies just follow industry "standard" numbers with tried and true suspension platforms and then update them as fashions change. It's very hard for a bike like that to be bad and all the reviewers can really do is comment on the quality of construction, the build kit and give pretty generic feedback about the ride.
When a company does something different, like uses a new suspension design (nalid react 2 play is a new one) or does something interesting then you get some more interesting reviews and feedback. But most bikes are just super similar and all pretty good.
You don't want a Badmountain day (badminton)
Regardless, "faster" isn't the only feature of a bike I'm interested in, which is kind of the point.
As far as safety, a longer/slacker/lower bike is just as dangerous in the hands of an inexperienced rider as a 90s URT bike with rim brakes. That'll never change.
Race bikes are better than ever, but not everyone wants a race bike. I just hope the manufacturers reflect that in a diversity of offerings.
Far too many riders falsely imagine that alloy rims have more vertical compliance than carbon rims, that they "conform" better to trail chatter, and that this explains the difference they feel (or perceive they feel). The well-documented reality is that any properly tensioned bicycle wheel, as a pre-tensioned structure, has so little vertical compliance under the vast majority of its use that it is indistinguishable. Generally speaking, even under a high load event, a typical alloy rim would have roughly 0.5mm of vertical deflection, while a similar carbon rim wheel would have 0.25mm of deflection. Meanwhile, the tire may have 25mm to 50mm of deflection. Kudos to those amazing riders who can distinguish the 0.25mm from the 50mm.
In my opinion, Pinkbike readers would be better served by an article that explains what "stiffness" really means in a pre-tensioned bicycle wheel structure, what variables influence the actual measurable attributes that constitute stiffness, and some (possibly subjective) discussion of how those attributes translate to ride quality/behavior.
Sufficient spoke system stiffness (more spokes, greater bracing angles, thicker spokes) will counteract this transfer. The worst case scenario for rubbing brakes or chainstays would be a very stiff rim and a very low spoke count, thin spokes, on narrow flanged hubs.
Ironically, your direct experiences may be a result of the stiffness of your alloy rims, and the lack of stiffness of your spoke system, rather than your assumed explanation of the rim flexibility.
My main criticism is the implication that carbon rims are inherently stiffer and aluminum rims are inherently softer. We're starting to see carbon rims with very low section height, which could have less radial - and maybe lateral? - stiffness than many aluminum rims.
I agree the 35 mm bar clamp standard usually produces a harsh ride, but if I could get the same amount of additional flex from my tires or rims as with a 31.8 mm bar, maybe the combination of a stiffer bar and softer tire/wheel would be equally comfortable and more precise.
Another benefit of compliance at the tire or rim is that it's unsprung mass. A fork can react only so quickly; it's not efficient at handling the size and frequency of impacts that can be handled by a compliant tire and rim.
The design of a wheel and tire, such as rim shape, spoke bracing angles, rim width, etc. offer enough variables that we can address the cliché "laterally stiff and vertically compliant" objective. I agree with the objectives you've described and I think tires and rims are the most efficient way to get there.
WRT to vertical compliance in rims, is possible that additional lateral compliance in alloy rims is what's responsible for the preferable ride characteristics? How do you know that the difference of .25mm of vertical deflection is being absorbed by the tires? Have you done a scientific test?
Lateral deflection (or lack thereof) is certainly a valid attribute that might explain some differences in ride characteristics. So why not measure it? Its not particularly hard to do.
As for the 0.25mm vertical defection number, that's direct math. Forgive me for not subjecting Pinkbike readers to the equations, but spokes are steel, how much it stretches under tension can be directly computed, the corresponding rim movement as that tension decreases can also be directly computed. Assumptions are required, so the number isn't exact, but the scale is. Whether its 0.17mm or 0.31mm doesn't really matter. Its the proportion of those tiny numbers to other variables that I'm pointing out. As for the 25mm to 50mm of tire deflection, that's simple: you can sit on your bike and a buddy can directly measure the "sag" from the tires at 5-10mm. Or consider a bottom-out event where the tire touches (or nearly touches) the rim; in that case, its roughly the tire cross section that deforms. Again, its not the exact number that's important. But there's no arguing that MTB tire deflection is ~ 100X the scale of rim deflection.
3.0 tires on regular trails pretty much suck for lighter riders who have to run crazy low pressures in them. For bigger(200+) riders who ride 3.0 tires at higher PSI(15 or more), they're wonderful! I use this as an example because I'm bitter that Maxxis is dropping all 3.0 tires.
I did notice during Specialized's Spring sale they were blowing out Purgatory & Ground Control 27.5 x 3.0 tires for $40, those are the only two 3" in their lineup...2.8" tires were not on sale. Will be interesting to see what they spec the next run of plus Fuse/Stumpjumper with.
A buddy did speak highly of the Nobl carbon, and he's similar size and rides for fun more than race times(abuses wheels). He is still on 26 though
Oh, and my opinion on 29ers - they have more mass in the tire/rim, so of course they feel like they roll over stuff easier - it's called centrifugal force. But that same mass takes more energy to start and stop, so the smaller wheels feel more livelier and responsive. To give the 29er the same strength as a 26" the rim will require more material. It's simple applied physics.
1) start riding a lot
2) buy lighter components until you get failures
3) go back to components that don't fail
4) basically use those components forever
My most recent bike came with Ethirteen carbon wheels. I've already put the rear out of tru and all spokes have similar tension, so I'm not sure how long this wheel is going to last me(too damn expensive!) I was looking at the Spank wheels as an option, though if I recall they're quite heavy
Also think about rebleeding your damper with lighter oil.
Having the right oil weight will open up the option of actually using the external adjustments that came on your fork.
They noticeably increased arm pump and overall fatigue.
That's been my experience anyway.
Just using standard alu rims with 32 spokes now and happier
At 165lbs I find most carbon rims too harsh (long rough dscents) on my 27.5 bike. However I prefer the carbon rims on my 29er. I like the extra stiffness cornering and the reduced weight with the larger carbon rim. The carbon 29er rims seem less harsh also. Giant Reign 27.5 vs. Trance 29
Yea, I wouldn't start there either, I'd also definitely jump to changing my wheels out.
One thing is changing the marketing tune from stiffer = better. That conversation is already starting to happen and articles like this are good step. A completely different challenge is changing the production methods for the vast majority of carbon mtb goods. Composites design for appropriate stiffness involves a lot of prototyping as the FEA methods just don't seem to be there yet. Asian carbon production is going to struggle from "making it so it doesn't break" to making it with appropriate compliance, it is a whole order of magnitude more complicated and demands much more precision. I really only see this happening if production comes back to Europe and North America at a much larger scale than today. And I don't see that happening because people are already screaming about how much bikes cost.
So, expect big budget marketing departments to continue to spew stiffer = better for the foreseeable future while smaller niche players offer up more interesting alternatives at smaller niche prices.
It's insane how much money goes to marketing and the people who create this BS.
Lot's of time and money wasted just to come up with the most utterly BS that even a chimp at the zoo could do better.
But that's everywhere, not just the bike industry.
The company I work for wasted half a year and god knows how much money to come up with a 2 word marketing catchphrase that is just so dump.
They shold have asked me.
I could have done the same in 5 minutes for a nice big Döner LOL
Fox has relatively extensive marketing and in my opinion overpriced products (certainly in Europe). Manitou and X-Fusion have excellent performance and value for money.
Which brand sells better and which approach is rewarded by customers by buying their products?
The same goes for other components and bikes themselves. Unfortunately, consumers don't always (as in almost never) behave in a way that is beneficial to them in the long run.
Of course it works, or else they woluldn't do it.
@Ttimer No, you wouldn't get better/cheaper bikes if marketing/sales/advertising money was put into engineering. Instead, you would get lots of closed down, bankrupt companies, engineers looking for other jobs and less competition with a few big brands dictating the prices/quality (i.e. more expensive/worse). YT or Canyon would never have happened and I'm sure you realise their investment primarily in sales and marketing played a big part in why we can now buy good, affordable bikes - not just from them but also other brands thanks to a change in the market.
The best product will disappear and be forgotten if you can't sell it. @Mac1987 's Manitou/Fox example is a good one.
If you want a good bike at a low price today you need to buy at companies with less media presence, like Radon or Rose.
And your hypothesis about marketing and competition is simply wrong. Marketing goes hand in hand with market power and markets with low levels of advertising/influencing/BS/sponsoring/publicity tend to be less concentrated.
I bet with a good set of wt Maxxis tires you would have plenty of traction.
Am I wrong? What am I missing here? It sounds like we are talking about a road bike not FS MTB.
I have a fat bike too so psi changes are important depending on conditions.
These days, I pretty much only ride one bike, it's a modern, long, slack trail/enduro/AM/whatever bike that I can pedal all day, or take to the bike park.
I have two wheelsets for it, one lightweight carbon, shod in some trail weight tires, that really makes a huge difference for those 4+ hour pedal fests. I know I can't push them that hard, but the riding I do when I'm in pedal mode doesn't generally involve off-camber rock chutes, so not a big deal.
When it's time to hit the bike park or some trails that have the color black in their rating, I throw on the aluminum rims running DH tires and cushcore. Quite a bit heavier, no where near as efficient, but way more traction and way more durable.
I think you'd hit the nail on the head- but I would recommend instead of having two bikes, just have two wheelsets. Modern long travel trail/enduro bikes are so capable at doing multitasking that I am genuinely questioning whether most riders need more than just that bike (and yes, two years ago I would have called myself an idiot for that statement, but now I'm not so sure).
At least if we're talking dh vs enduro bikes, there is no replacement for a proper big bike when hitting the park or race tracks. Yes you can ride them on a enduro, but your confidence levels are way lower (for most people) and they will inevitably start doging out on some sections, go slower and start making excuses because of the bike they're on. I've seen it happen a lot.
The thing is you just don't notice it yourself,especially when in a group who all do the same.
I also own a dh and a 170mm enduro with proper aggressive geo. There's still no comparison between the two in terms of the confidence they inspire on a proper track.
It's not an economically valid investment of course and from a financial standpoint the one bike quiver is totally fine, but there are definitely points to be made for more than one bike.
Well, i always assume proper tracks are a given when people talk about how capable modern enduro bikes are.
If we´re talking buff trails, you´re totally right, an enduro can be great for these. However, there´s not really a point to comparing bikes on these as a hardtail will be even better/faster in many cases. I´m totally with you though, ride whatever feels best to you. That said, i never felt overgunned with my dh bike on flow trails. You just get away with more stupid stuff, like sending it to flat.
When people talk about a bikes capabilities, i have to assume we´re talking tracks that actually warrant aggressive geo and suspension and actually pushing the bike to its (or the riders) limits on such trails. For those, even though enduros are quite capable, nothing beats a dedicated dh bike imho. Then again most people are quite happy with just making it down the mountain in one piece. So if all you´re looking for is something that gets you down, they´re totally fine. In the end it probably just comes down to personal expectations. I just dislike the blank statement that enduros are just as capable as downhill bikes, which is definitely not the case.
Bruce Lee
Not sure how that will translate to wheels though
That's what I've been told at least. I'm a hack though myself.
i've seen repeated articles and opinion pieces where other authors maintain that they can feel the difference based just on rim material. perhaps i am not as sensitive as others, but I've ridden all sorts of wheels in all three wheels sizes, both alloy and carbon, and never felt that the ride quality was all that different. it seems that a small change in air pressure would result in far greater deflection of the tire sidewall than any modern wheel would ever flex. that being said, my enve carbon dh bars feel different than the raceface sixc bars and definitely different than the atlas ally bars i used before... but of course you're more directly connected to the bars than the wheels.
what do you reckon?
I have ridden Enves before however, and rolled a tire right off the rim in a hard corner. Stiffness of the rim vs. improper pressure from my weight? Possibly.
Probably not something the average rider will be able to test much in detail though as you say, having a few spare wheels and a box of handlebars and stems might get expensive.....
Its interesting to see how much thought / testing they put into this subject in Moto GP too, continuously manipulating design and material choice to achieve the required stiffness in areas such as fork crowns and swingarms etc.
Sorry I ranted a little bit.
The wheelset was manufactured and built by a small boutique wheel brand and they hooked me up with a replacement for basically the cost of shipping and labor. I just monitor my tire pressure more closely and haven’t had a problem since and now run carbon wheels on all my bikes- one set of enves, some ibises and some specialized and none of them have been anything but perfect from day one.
That said, more than a few carbon rim manufacturers claim that their rims are actually designed to be more compliant and we're getting inserts that go (almost) directly against the tire wall that are also supposed to provide damping. Mr. Wolf and Tannus come to mind. Not saying I've ridden any of these (nor have I ridden a carbon rim) but in this time it may be an interesting experiment. To see if an insert with damping could actually tame a carbon wheel and make it useful for whom a regular tubeless wheel with a carbon rim would be too harsh.
dirtmountainbike.com/features/carbon-mtb-wheels-do-you-need-them.html
Obv. this is a simplification, but adding complexity to make up for problems that can be solved by reducing complexity seems like a losing proposition.
@WAKIdesigns 1. How do you know that racers wouldn't be on lighter bikes if they could get the same performance? 2. Not everyone is a racer, some are in it for other types of fun, especially on a trailbike. That tends to be forgotten among all the Enduro-Bro, "slay the trails", STRAVA chest-thumping.
So my suggestion was more of an open minded one. If you can make a carbon wheel less harsh using inserts, would you still experience any advantage over an aluminium rim with an insert? We can argue about it but I thought just because they probably have that kind of stuff ready at the office, why not have an open mind and test it instead?
I'm not using the insert (ProCore in my case) just for compliance (to be able to run less pressure in the tire) but also to protect my rim when doing so. Even though I run aluminium rims (Syntace W35 currently) I still like to protect them even if it weights a little more.
There are of course many other reasons for using inserts.
My experience with standard tubeless is that it is dead-simple to set up with just a floor pump and a spray bottle of water. I can hardly imagine Procore to be even more simple.
I had all that in mind as I watched the arrival of carbon rims, and smiled as I saw the marketing talk about introducing compliance in the rim. To me, carbon rims, low spoke counts, wider hub spacing, were all just solutions in search of a problem (cough*wagon wheels*cough).
I have a buddy on a Pivot 429 who bought some Enve rims. He hates the way the bike feels, and finds he gets bounced around and knocked about on rough downhills. He wants to sell the bike and get something with 140mm travel. I keep telling him to just get aluminum rims, but he thinks it would be a "step back". to which I roll my eyes. I just sent him this article, so thanks for that!
@Ttimer: Yeah again I didn't mean to say it is bound to be a success, just meant to say that if the carbon rims you have feel harsh then why not try to solve that using inserts while you're at it? I personally believe that harshness doesn't necessarily come from stiffness, but from lack of damping. Steel frames aren't designed to be less stiff than aluminium frames, but there is more damping in the material. So yeah my point was, maybe there is something to like about stiff wheels if there is a way to filter out the excess vibrations, like some of these mentioned inserts could. Maybe not. As I said, as they have the stuff over there already, why not try it out? I don't care much about weight. Unless you're starting from a start gate like in 4X racing, I doubt it matters much that it is harder to accelerate. And if you tilt the bike properly when cornering, it definitely won't make it harder to change direction. Unsprung weight? If that is such an issue, then just buck the trend, get a 2X drivetrain instead of a dinner plate and get all your water and tools off the bike and into your backpack.
@slyfink: Yeah, I've got a Cannondale Prophet and indeed the flex in the swingarm was always what the reviewers appreciated when cornering. I also recall that back when RockShox considered moving up to 35mm stanchions one of their concerns was that the fork would be too stiff. It turned out to be fine (or they tweaked it somewhere else) but at least they didn't go all the way up to 40mm or even 38 to match their competitors. I also recall that when Stanton increased their seattube diameter to fit dropper seatposts, they didn't get much love because reviewers felt the character was gone. They tweaked it in their next version. So yeah, too stiff is definitely an issue. It leads to higher frequency vibrations which are considered uncomfortable.
XC:
carbon: stiffness at low weight
alu: N/A
Down Country:
carbon: stiffness at comparable weight,
alu: price
Enduro/DH:
aluminium: compliance, robustness, price
carbon: N/A
Overall pros:
Alu: compliance, price
Carbon: no need to true, no need to fix dents.
other piece of the puzzle I think may be testing carbon vs. alloy bars,
like Spank’s Vibrocore, to see how The System feels and performs.
I liked the carbon wheels on the steel hardtail precisely because the steel already has a certain amount of whippiness to it.
When I had bird arms I couldn’t handle the stiffness but now that I’ve bumped to 15 lb dumbbells I can hammer thru stuff and really take advantage of the stiffness.
Basically get swoll and carbon is better. Otherwise just cruise around and it doesn’t matter.
Well, I dumped the cheap stock wheels and put some Chinese cheap carbon hoops on, and it was night and day better performance. I realized that the aluminum rims, at 29 inches, flexed sideways a ton (a properly tensioned wheel will only flex vertically like half a millimeter, look it up) which probably contributed to the sidewall flex in turns. They also had to be trued almost every other ride. I have yet to need to true a carbon rim, and I've been through several sets from several cheap Chinese brands. The OG Enduro 29 still had its issues, but man it was so much better with carbon rims. I felt no extra arm pump or a decrease in traction.
That being said, working at a shop in central Texas with lots of chattery cheese-grater limestone around (on the trails rated for MOARFUNN) I always highly recommend the DT XM481 rim when folks are looking to lace up something sweet. We do a lot of Flow’s too.
But you can’t complain about carbon with the warranties that are currently available.
I wonder if MTB frames have reached the point where we need a bit of flex lateral flex built in (either to the frame or the wheels) to assist with traction when leaning over. Obviously we're not reaching the same lean angles as in MotoGP but we're also riding on bumpier ground.
Bring on the neg props, the more the better!!
You say this but contradict yourself in the same paragraph:
You say:
"...but I was struggling for traction. On off-cambers and hardpack terrain the bike was skittish and I found it hard to hold a line."
then
"I didn't want to play too much with fork setup or tire pressures and casings as I had found a setup that worked for me"
Maybe those are the things you need to change to counteract the stiffness of the carbon wheels? Maybe you are running tires that aren't suited for carbon wheels, maybe your pressure in the rear tire is too high, maybe you need to dial in your suspension to be more supple for carbon wheels?
Saying you found a problem with traction, but then saying you don't want to change your suspension, tires, and tire pressure because those are perfect? They don't seem to be perfect since you are saying you are having traction issues. You seem to be ignoring the obvious, because you think you have your setup correct, when in actuality, these are the things you should be changing.
Then you go on to say this:
"This test has lead me to believe that we should be looking at our bikes as systems, not collections of components."
You are correct on this, but you are ignoring your own advice, and changing just a component, instead of setting up your bike system correctly for the sum of the components to make it a system. You say you aren't getting traction, and you only want to change your wheels. Wheels do help with traction, but what helps with traction more than wheels is a bike system that is setup correctly for your collection of components. By ignoring the things you don't want to change because you say that setup "works" (which obviously it doesn't, since you are losing traction), you are ignoring your own advice and treating your bike as a collection of components compared to the bike as a system.
This is like going to the doctor telling him you can't walk, and the doctor says, well you have a broken leg, and then you tell the doctor to ignore what's obvious, the broken leg, and that you believe your problem is your hip, and not your leg, as you say your leg is fine and you don't want him to touch your leg. So hey replace your hip at your request, and you see some improvement, but your actual problem still exists, just because you think everything else is ok, when it's not.
Sadly you contradict yourself and ignore your own advice all in one article.
//end rant
Great little video about compliance and cornering grip. Subject is steel frames, but same idea as this article.
I´m riding the carbon rims on my Turner DHR now and they work perfect on that setup.
Hey Matt nice article. I went through exactly same process (same carbon rims Ibis 741) when moving from my 2015 Devinci Spartan to 2018 Pivot Firebird. The Pivot has a very stiff frame, so when paired to carbon rims it gave an akward feeling that translated in early fatigue and less control of the bike in certain situations. I agree that one must look at bikes as a whole and that it also depends on personal preference. What one can conclude though is that a same wheelset will NOT perform the same on different bikes. Simple as that.
I notice a bit more non-compliance than I'd like in my carbon wheels on carbon frame when descending, and I also have a moderate need to pick my lines reasonably well rather than blast through rock gardens. I'm fast, but not point-and-shoot fast. I acknowledge that some people find the latter the high point of their riding experience.
But it's a tradeoff I'm happy to make for my situation, which includes massive climbing every ride. I enjoy climbing a lot, and I enjoy it much more with my highly-responsive carbon wheels, where I make fun little mini-sprints out of the climbing turns that I believe contribute power training to my other sports.
So for my use case of all-mountain round trips, I'm convinced that light carbon wheels are best.
Is the CB Synthesis philosophy of a compliant wheel up front and a very stiff wheel in the rear, a sound one?
Or should a CF wheel build focus on compliance front AND rear? Is more better, or not really in all cases?
Thanks for your input.
1. If you ride hard and fast you 100% will break your carbon rims eventually.
2. Your buddies will keep riding and you will be side lined until your fantastic warranty rims are returned.
3. If you love riding you those grams you saved with carbon aren’t so sweet because those days you sit trackside feel like weeks.
That said, while the people i know who race CX, road, and XC don't break carbon wheels, the ones who race enduro and downhill do. They trash alloy rims too, but it's less expensive. Those wheel breakers also do appreciate the stiffness of the carbon rims when they're in one piece.
It reminds me about a story a hardcore 50y/o + windsurfer dude told me.
Company's in the surfing industry started pushing the tech way to much and it kind of ruined the sport in some way (in the surfer his eyes). Just regular people were surfing on pro boards + huge sails and were not having a good time anymore. They were professionalizing the tech way to much and it took a lot of the fun factor out.
A well designed carbon frame is not just aimed at reducing weight but to achieve specific compliance effects.
You are aware that aluminum does not naturally occur in it's pure form, or even any useable alloys, right? It has to be refined out of bauxite ore, then further mixed into the desired alloy, then precipitation hardened (usually), then machined/welded, and heat treated again.
The manufacturing chain for carbon fiber is more labor and capital intensive, but it also involves fewer steps.
We've officially reached peak pinkbike.
youtu.be/RlgDlyMmUaw?t=82
I went from LB 38mm carbon to DT XM481 alum, LB carbon feels responsive but imo it's too stiff, I prefer the DTs.
that's what she said
1 - you have money to burn.
2 -you're sponsored.