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8/29/2010
Location
Grand Junction, CO
US
Edited Date/Time
10/19/2019 2:13pm
The Internet Was Wrong: Short Chainstays Suck*
****Disclaimer - Full on bike geekery below - eyes *may* glaze over while reading***
First, a story. Many years ago the bike world was convinced the shorter the rear end of the bike, the better it would corner. Or rather, the easier it was to change direction.The internet forums were rife with thread after thread looking for a bike with the shortest rear end one could cram into a bike. The first iteration of the Specailized Demo circa 2005 really reflected this trend on the longer travel side of things with 16.9" stays. Coincidentally, me owning this bike correlated to my last season of DH racing. My times sucked, I never felt comfortable, and couldn't figure out why.
Fast forward to today, bikes have grown substantially in overall length but many manufacturers are still spec-ing incredibly short rear ends. As many of you know, I ski 6 months a year. This trend of long bikes and short CSs would be akin to skis getting substantially longer but mount points staying in the same location (same amount of tail). For the skiers out there, one can only imagine how silly it'd be to ski a 195 with a -31CM mount point - in short, it'd be terrifying.
Your top two finishers this weekend were both on bikes with "long" (by today's trail bike standards) chainstays. To add, neither of these riders are super tall and both (likely) riding medium frames.
Richie Rude: SB 6c medium - 17.4" chainstays
Sam Hill: NukeProof Mega (guessing a medium) 17.5" chainstays
First things first, yes, both Sam and Richie have talent that is far beyond what any of us that hang around Vital can comprehend, let alone emulate. Put another way, its the the artist, not the brush, and no amount of bike geekery will turn one of "us" into one of "them".
Still, as bikes have grown in length, I've noted this strange push and pull. On one hand I feel much more comfortable on the bike. (EG, my knees don't hit my handlebar, and I no longer look like a circus bear riding a tiny bike) On the other hand its become increasingly hard to get enough weight on the front tire.
When bikes had wheelbases that were 2-3" shorter than today's standard, it would make sense that a short rear center would offer a fairly balanced ride, especially in the small and medium sizes. However, as bikes have grown in front center, manufacturers have stuck by the internet driven adage that "long chainstays suck". Don't get me wrong, for a number of bikes, short rear centers make sense. But for bikes built for aggressive riders trying to go fast, short rear centers are dream crushing, especially in larger sizes.
From a race results perspective, one needs to go no further than Aaron Gwin's first season on Specialized to see what a shorter rear end can do for one of the fastest guys on the planet (he had a bad season until they lengthened the rear end). Minnaar famously had a few breakout races on the now-legendary (yeah, I said it) XXL V10 (with ghastly long 17.75" stays). Even Sam Hill has lengthened his Nukeproof DH bike's rear end to get more weight on the front tire.
This post is meant as a call out for manufacturers to start recognizing this need for longer rear ends to compliment the longer front end. Simply, longer CS measurements are needed to balance the bike. Ideally, each size would have a different rear center (norco does this - getting longer as the size goes up - though they are still too short) to keep this balance in check, but I realize this can be extremely cost prohibitive.
There are objective ways to "test" for this balance, which I won't go into here. But yes, in an XL size, I'd like to see a "throwback" to 17.5-17.75" stays.
Likely? Probably not. But maybe one or two manufacturers will take note and start offering stuff that really is balanced in the larger sizes. The real irony is longer stays can actually make a bike corner **better**, so long as its all kept in proportion.
Without being too long winded, I leave you with the wisdom of Walter Sobcek...(am I wrong?)
Discuss amongst yourselves.
(PS, Team Robot said this a year ago)
*short chainstays are totally legitimate in kids bikes, short people bikes, XS bikes, dirt jumpers, and "I only ride park - bikes"
****Disclaimer - Full on bike geekery below - eyes *may* glaze over while reading***
First, a story. Many years ago the bike world was convinced the shorter the rear end of the bike, the better it would corner. Or rather, the easier it was to change direction.The internet forums were rife with thread after thread looking for a bike with the shortest rear end one could cram into a bike. The first iteration of the Specailized Demo circa 2005 really reflected this trend on the longer travel side of things with 16.9" stays. Coincidentally, me owning this bike correlated to my last season of DH racing. My times sucked, I never felt comfortable, and couldn't figure out why.
Fast forward to today, bikes have grown substantially in overall length but many manufacturers are still spec-ing incredibly short rear ends. As many of you know, I ski 6 months a year. This trend of long bikes and short CSs would be akin to skis getting substantially longer but mount points staying in the same location (same amount of tail). For the skiers out there, one can only imagine how silly it'd be to ski a 195 with a -31CM mount point - in short, it'd be terrifying.
Your top two finishers this weekend were both on bikes with "long" (by today's trail bike standards) chainstays. To add, neither of these riders are super tall and both (likely) riding medium frames.
Richie Rude: SB 6c medium - 17.4" chainstays
Sam Hill: NukeProof Mega (guessing a medium) 17.5" chainstays
First things first, yes, both Sam and Richie have talent that is far beyond what any of us that hang around Vital can comprehend, let alone emulate. Put another way, its the the artist, not the brush, and no amount of bike geekery will turn one of "us" into one of "them".
Still, as bikes have grown in length, I've noted this strange push and pull. On one hand I feel much more comfortable on the bike. (EG, my knees don't hit my handlebar, and I no longer look like a circus bear riding a tiny bike) On the other hand its become increasingly hard to get enough weight on the front tire.
When bikes had wheelbases that were 2-3" shorter than today's standard, it would make sense that a short rear center would offer a fairly balanced ride, especially in the small and medium sizes. However, as bikes have grown in front center, manufacturers have stuck by the internet driven adage that "long chainstays suck". Don't get me wrong, for a number of bikes, short rear centers make sense. But for bikes built for aggressive riders trying to go fast, short rear centers are dream crushing, especially in larger sizes.
From a race results perspective, one needs to go no further than Aaron Gwin's first season on Specialized to see what a shorter rear end can do for one of the fastest guys on the planet (he had a bad season until they lengthened the rear end). Minnaar famously had a few breakout races on the now-legendary (yeah, I said it) XXL V10 (with ghastly long 17.75" stays). Even Sam Hill has lengthened his Nukeproof DH bike's rear end to get more weight on the front tire.
This post is meant as a call out for manufacturers to start recognizing this need for longer rear ends to compliment the longer front end. Simply, longer CS measurements are needed to balance the bike. Ideally, each size would have a different rear center (norco does this - getting longer as the size goes up - though they are still too short) to keep this balance in check, but I realize this can be extremely cost prohibitive.
There are objective ways to "test" for this balance, which I won't go into here. But yes, in an XL size, I'd like to see a "throwback" to 17.5-17.75" stays.
Likely? Probably not. But maybe one or two manufacturers will take note and start offering stuff that really is balanced in the larger sizes. The real irony is longer stays can actually make a bike corner **better**, so long as its all kept in proportion.
Without being too long winded, I leave you with the wisdom of Walter Sobcek...(am I wrong?)
Discuss amongst yourselves.
(PS, Team Robot said this a year ago)
*short chainstays are totally legitimate in kids bikes, short people bikes, XS bikes, dirt jumpers, and "I only ride park - bikes"
Have you tried longer stays? Remember, I'm not arguing I need long stays for stability, but to more naturally weight the bike properly. I'm actually arguing I turn a bike **better** with longer stays (to a point) as it allows me to get my weight on the front of the bike while remaining in a more neutral riding position.
Put your front and back wheel on two scales. Have someone support the bike. Climb aboard and get in your attack position. I'd wager you are weighting the rear wheel a lot more than your front, even for a downhill bike. (I'd argue 48/52 front/back is appropriate for trail/enduro, 45/55 DH)
EDIT: one of the difficult things about this is body types/riding styles/etc are heavily going to play into the results. Hence, maybe what you are building is great for you...but I'd still be curious if you've really played with CSs all that much - and extremely curious what the scales say.
Also I think you touched on something in your recent post about riding styles having an effect on weight balance etc. It seems that head tube angles have settled down now but we went through a period of bikes getting slacker and slacker because 'that's what the pros ride'. Well I'll wager very few of us have the confidence and ability to weight the front wheel of a bike like the pros do. Trends have a way of sending us down a path that might not actually beneficial for the regular guy.
When a race car is set up, it is corner weighted, with ballast moved around to equalise weight distribution across all four wheels. I understand that the majority of the mass of a bicycle+rider is the rider, but I don't see why this sort of logic isn't applied more at the top level of our sport. Maybe it is in a way, but probably more through feel, and 'tweaking' the setup rather than some kind of quantitative analysis. I know they are starting to make a joke about Minnaars fiddling with his setup by tiny amounts here and there, but he is finely tuned into his equipment and I'm sure it makes a difference. If only there was a way to actually measure the effects of those changes.
As far as slack head tube angles go, I too agree. Unless you are charging super steep tracks and have the balls to stick your head way over your front wheel, they can be challenging to ride. That said, I've found slacker HTs easier to ride as the rear grows. I also believe slack head tube angles are excellent for newer riders as it can keep them from OTBing it too much. Its us middle-of-the-road riders that really don't benefit from uber slack bikes.
Looking at the EWS example, it makes sense to have longer bikes for maximum stability since they are only timed going down, and the climbs are fire roads or shuttle/lift assisted (also the reason they can get away with 180mm forks). For those of us that pedal an up on mixed terrain as well as going down a compromise between long and short is needed.
All this pontificating about front-rear weight distribution is a little ridiculous. If you keep the wheelbase the same and go from 16.9" chainstays to 17.5" chainstays, that amounts to moving your feet 0.6", while keeping everything else the same. Given that when standing on the pedals you can move your whole body back and forth, the total change in your center of mass position is really small. Your body's max rearward position is limited by your arms, not your BB position, and max forward position is irrelevant, since you never go there.
Does not feel right slack.
On the other side of the coin, I love having short stays on my Demo 8 because I know I'm not fast, and don't try to be, that bike is purely for fun.
So I think it boils down to - do you want to have fun doing stupid shit and go slow? Then short is great. Do you want to have fun going fast? Then long is great.
But as has already been established, it needs to be proportional to rider size / bike size. Short TT long rear end is just as silly as Short rear end long TT.
From seeing how much the weight balance changes dynamically some may say "so then simply adjust weight balance by using your riding position". But I digress, a better balanced bike still puts you in a better position to begin with and THEN you can really start to play with your upper body.
So, definitely support the OP's statement. Just got myself a Giant Glory in S (me 5'7"), found out it's way longer than Giant's geometry table suggests, and installed a plus-1-degree headset. Shortened front center, slightly longer reach, havin' a blast in turns now!
Anyway, the longer chainstay topic is easy to get your head around. But what happens when you go to longer reach values (at constant CS)? Don't you get to a point with increasing reach, where the upper body is tilted so much to the front as to have the same effect of weighting the front wheel?
If you know what you like that's cool, I'm not telling you guys what to ride but if you've not tried it then you really should.
Ps I've been saying this for years but who's counting ;-)
While longer CS has better performance over raw chunky terrain, that's not necessarily where people have fun. People will ride trails conveniently located close to home. Such places tend to get new lines shaped into them that suit their current bikes. This is how park style riding is sort of born.
Can argue either way. The short CS crowd have their 50:01 movement. What's the longer CS crowd have? Using race results and anecdotal evidence saying you're a better ride on longer CS just isn't as rad as styling it out, I guess.
I thought my long CS bike was a ground hugger. Excellent for control, but numb to the point that speed was its only redeeming point. Traded it out for a hardtail, and now back on a medium-length CS (17.0") FS bike as sort of a compromise. One thing I certainly don't miss is how hard the rear wheel was taking an absolute pounding, getting pinch flats, etc. with 420mm (16.5") CS.
You can only go so long with the front end until the bike just becomes too big. Ok so the effect is to even out the weight distribution across the bike, but at what cost. The rider will be in a compromised position, limiting the effect of the rider, and the body won't function at it's most efficient or powerful. Increasing the front centre puts more force through the riders upper body, possibly increasing fatigue (relevant for all disciplines). The same weight distribution across the wheels could be achieved by lengthening the rear of the bike instead.
In my opinion, what you really want is the rider to be in a neutral position, where his whole body weight is distributed across the bike to suit his preference. There should be room for the rider to move his weight forward and backwards by enough to manoeuvre the bike in turns and over obstacles on the trail. As a personal test I stand on my bike in normal riding position and loosen my grip on the bars. I should be able to stand like this without feeling like I'm falling forwards or backwards.
I think we are reaching the limits on bike length, especially for downhill bikes. Think back to the recent world cup in Lenzerheide, where several riders were struggling with going OTB at the 'Plunge' in the woods. These are the top riders in the world, and even they were finding it difficult to manage such an extreme feature on the track. Tiredness + long bike makes it difficult to pick that front end up and react quickly.
One more thought, though. We're talking small differences here, but I recently went back to a slightly shorter front center (WB 1227, reach 410, CS 443) and feel it's great, my riding did improve noticeably this first half of the season.
But my last Bike, Turner DHR, had reach 424, WB 1232 and CS 442. So slightly longer front end. And on that bike I had moments that I cannot forget. Whenever I managed to stand up high in the bike (neutrally) and use body tension (core muscles) to rotate the bike in turns and keep the weight balance, then even the steepest, technical sections were a breeze. The bike really lit up in those moments and I could place the front wheel on anything and not loose traction. Me being me, aka not the supertrained dude, these moments were rare and depended on daily form.
I feel that this could be another feature that distinguishes the John Does from the Pros, apart from bike handling skills. Their core strength is probably way above what most of us have, so perhaps much higher body tension is another reason why pros can make long-reach bikes work much better. I suggest because of their fitness they keep composure and are less fatigued, despite a more forward position in the bike.
Dude, 0.6" is huge. Put yourself and your bike on the scales and check the difference when, in riding position, moving your upper body back and forth. Weight balance is so fragile, you can easily achieve a delta of ten pounds. Do yourself a favor and check it out, it's an eye-opener.
Well, you've just repeated my argument back to me. Moving your ankles forward or back 0.6" is a tiny change compared to moving your upper body. The OP is misattributing the differences he feels to chainstay length in particular when they are more appropriately attributed to wheelbase and head tube angle.
I had a demo 8 in 2012, the rear end was "diving" on jumps, I didn't felt too confortable on long jumps If you look at videos of sam hill and troy back in the day, it catch all the time my attention. It looks like they were all landing "hard" on back wheel. I believe the body weight distribution wasn't well center. it was deffinetly good to manual some bumps but never felt as good "safe" on jumping.
I ride a demo 2016 alloy this year, feel a lot better with the bike, the move on 650B and a little increase of the bike's length front and rear make me feel a little bit more center.
PS : I "don't pay" for bikes or if I do, I try to spend the less as possible, internet is a good alternative for that at the moment.. I prefer to spend my money in traveling the "world" with my bikes
What we've found out is that a longer bike isn't just to give you stability to keep you safe, it is simply faster. Every time we've tried a shorter reach or chainstays - after a timed run before checking the time - we've always felt like we hauled ass and it must have been fast, but the clock doesn't lie. With slack head angles, longer chainstays definitely help you weigh your front on the turns so you feel planted in the turns. And that in turn makes it possible to have a really slack head angle and feel comfortable on it. And the long chainstay also makes climbing with a slack head angle feel like a walk in the park
I think the silver bullet of chainstay length is to match it to the front-centre. If that isn's right then you have to compensate it while riding and usually coming out of corners you feel uncomfortable. My personal bike at the moment is a Large 140mm Pole Evolink (Reach 510mm/20.08in CS 456mm/17.95in) and I'm standing at 180cm (5.9 feet). Some might argue that it is too long for me but once you get comfortable with it there is no holding back. The longer bikes makes you more comfortable on highers speeds, rougher terrain, off cambers and in the corners the grip is endless. You end up leaning more in the corners, I feel like I lean in to the turn on the front tyre like I do on my KTM.
Longer chainstays on your AM/Trail/Enduro bike are key to letting your downhill bike collect dust in the garage.
Totally agree that upper body movement has a huge effect. But as I said, neutral balancing of front and rear center puts you in a better place to begin with. Because CS length changes the general weight balance of the bike, irrespective of body position.
Whereas the effect of longer reach is not so clear cut. On one hand it drives the upper body more forward, but on the other hand it reduces the load on the front wheel, when looking at the leverages while standing in the pedals (without handlebar contact).
Look at @Oz_Taylor's comment. You can overdo it with a long reach, as you may find yourself forced to lean forward more heavily to keep pressure on the front wheel. With too long a reach you compromise that neutral position (the position where one can lift the hands off the handlebar while standing, but weight balance in the bike remains intact). But this effect may depend on the specific weight distribution of the rider's body, which will be slightly different for every rider. So chainstays longer is an easier way forward for fitting a bike imo.
CS length changes the general weight balance of the bike, irrespective of body position? Again, 0.6" change in chainstay length, keeping wheelbase the same, has a very small effect on weight distribution compared to changing upper body position.
Longer reach drives the upper body forward? Not if you shorten the stem to keep the handlebars in the same place, which is how things are typically done. Sure, it lightens the load on the front wheel for a given angle of ground slope, but different people want their bikes optimized for different slopes.
Sure, you can overdo it with long reach or head tube angle, or chainstay length, or any design parameter. But, for the whole crop of modern bikes, these come down to preferences. Heck, just look at the change in weight distribution between flat ground, a 5 degree downslope, and a 10 degree downslope. It is bigger than swapping 0.6" of front-center for 0.6" of rear-center. Different people want their bikes optimized for different things, and ranting against some current bikes' chainstay lengths is misplaced.
Yes, irrespective of body position. All things equal (front center, WB, HA, and so on), the CS length determines the leverage that each wheel sees, without the body changing position. Shorten the CS, the back wheel shifts more underneath your ass --> more weight on the back, less on the front (both wheels always add up to 100%, duh). Lengthen the CS, back wheel sees less of your weight, automatically front wheel sees more. Nothing to discuss here, basic static mechanics. All other geometry equal, your body position doesnt change with CS length, that's why I said "irrespective". It does with reach though.
Shortening the stem with a longer reach is even more counter productive, if you want to get more weight on the front wheel. Because then you are simply moving the front wheel away from you without changing your upper body position. Mute argument anyway, cause we need to talk about change in one measure at a time, not multiple ones simultaneously. I was talking about change in reach only.
Your last paragraph has some truth in it. Yes, all these ambient changes are much more drastic. But I'm saying for the third time now, that frame geometry gives the baseline from which the rider reacts to ambient changes like downslope. So yes, it does make a difference, otherwise we would all still ride clunkers from Joe Breeze times or, worse, early '90 long-stem hillbillies.
Also, the OP did not rant about anything. He made an observation, which I can support:
2014, switching from Canyon Torque DHX (425 CS and 394 reach) to Glory (442 CS and 404 reach) was simply great. No more washing out front wheel, when I didnt lean all the way (and then some more) forward on the bike. Suddenly I was able to attack turns. Your experience is different? Be happy with it!
First, short chainstays (less than 17) often makes sense for smaller sized bikes. My title (short chainstays suck) wasn't really the point, what the title should have been was "chainstays need to be in proportion to the rest of the bike." In shorter reaches, 16.8-17" stays may make for a really balanced ride, but I can't comment being I ride 18.5-19" reach (XL) bikes.
Second, as much as its a throwback to a time I'd prefer not to revisit, adjustable chainstays could really make sense. Yes, I know, it changes your travel/leverage ratio too, but perhaps there is another way to do this that keeps travel the same (like how they lengthened the V10 without changing travel). Or maybe that's too complicated.
As far as SLP's comments about 0.6" not mattering, ankle position, the human head etc etc I guess all I can say is different strokes for different folks. How tall are you SLP? What size do you ride? I have a hunch you may be on a fairly balanced bike as is. (smaller size than me) Or maybe you are an outliar who likes a 40/60 weight distribution. Or you ride in Virgin Utah at the Rampage site
Again, to say I'm like Gwin, Minnaar, Hill etc is laughable at best. But for all three of these riders going to longer rear centers has helped their results immensely. Could they ride shorter rear ends? Absolutely! I'm just saying they certainly seem to be able to do everything better on more well balanced bikes.
With respect to my 27.5" trail bike, I'd like my chainstays to go from 16.9" to 17.7" and I'd like my reach to be shortened just a hair too. (about 1/2").
Will this change the bike? Absolutely. We all agree one or two degrees of headtube angle either way make a big difference, a few mm of fork offset make a big difference, 0.6" of travel can make a big difference - so why would it surprise any of us that a few mms of rear center can also change the bike's handling and weight distribution an incredible amount. In my experience, a little length here or there can make a big difference (that's what she said) as to how the bike feels..
To be clear, I'm not saying I "can't ride a bike with 16.9" stays and long reach". I'm just saying I have to fight the bike a bit more than I'd like when trying to ride fast for extended periods of tim. I don't feel well situated in my normal "neutral" position between the two wheels and the scales seem to objectively explain this. I can certainly find this position, but its an awkward position, one where I lose a fair amount of leverage and handling precision. Hence, this post.
Here is the kicker, some riders might be naturally in a good position and like the feel of short stays. And therein lies the problem. The human body is so different person to person. When we can adjust headtube angle (werks/angelset) stem, fork travel, stack height, bar height, to some extent bottom bracket etc but are completely limited when it comes to CSs it leaves many riders on bikes that don't quiet suit them, which again brings me back to "I want an adjustable rear end" comment...
Maybe a company should consider building a bike built for racing alone. Leave playfulness to other models. I see this in other sports. Skiing, sleds, moto etc. I realize the smaller companies couldn't do it, but the larger ones could do a "gravity special" with longer stays in the larger sizes and maybe higher end stiffer valved suspension.
But yeah, now I'm **really** getting carried away.
Thanks to everyone for indulging me in my rant! Good (bike nerd) stuff!!!
The OP started out with "The internet was wrong, short chainstays suck". Note the footnote associated with it: "*short chainstays are totally legitimate in kids bikes, short people bikes, XS bikes, dirt jumpers, and "I only ride park - bikes"
You close with something much more reasonable: "your experience is different, be happy with it".
Then OP came back a few minutes ago and moderated his tone, so we're all more relaxed now.
Nevertheless, reading your description, we were talking past each other a little bit. When I said "keep body position the same", I was referring to the following: Imagine two bikes with the same wheelbase, and the same positions of seat, handlebars, and body relative to the wheel contact patches. The only difference between the two bikes is that the BB is 0.6" further forward on one bike than the other (so yes, leg angles are slightly different). If we are discussing the effect of chainstay length in particular, that is the thought-experiment I find most relevant. I think you were imagining keeping body position the same relative to the BB, or something other than the wheel contact patches.
Anyway, the OP comes back and was driving at a point I often make: compared to the range of CS lengths from most major bike makers, variation in peoples' bodies (even for a given bike size) results in bigger weight distribution changes than the full range of commercially-available CS lengths. Similarly, compared to differences in typical trail slope from one person's home trails to the next, the effect of CS length within the range of currently-available bikes is small.
I want my next bike to have shorter chainstays than my current bike, but that is because I want a shorter wheelbase than my current bike. That is a more important effect than chainstay length in particular.
For example, a 26" full suspension bike with long stays may end up feeling similarly balanced to a 29er hardtail with short stays.
I agree that the shorter-is-better preference misses the big picture. But so does absolutely ruling out bikes with short stays.
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