Opinion: The Big Short - Smaller Wheels Don't Require Shorter Chainstays

Feb 8, 2024
by Matt Beer  
photo
Scott's brand new Ransom has a flip-chip to save the geometry when downsizing to a 27.5" rear wheel - well, an almost geometry saving flip-chip. The chainstay is chopped down from 440mm in the 29" setting, to 432mm with the smaller wheel.

Mountain bikers love meddling with dials, spacers, air pressures, …heck, anything that can be readjusted has probably been changed. Flip chips are one of those features commonly built into bikes to slacken or steepen the head angle within the manufacturers guidelines. We’ve also seen those invertible pieces used to change the suspension’s leverage rate, as seen on Trek’s Session. Another place they’re popped up more recently is on the rear triangle, allowing riders to switch between 27.5" and 29” rear wheels.

Lately, I’ve noticed a few new bike models which can accept either rear wheel sizes, but that comes with a compromise - the 29" chainstay is longer than the 27.5 setting. Take for example the new Scott Ransom and the Arc8 Extra.

You might think the rider who wants the smaller rear wheel is looking for more maneuverability, so surely they’d appreciate a shorter chainstay too. While that may be true to a degree, it drastically changes the tone of the bike. In fact, I’d argue that it potentially ruins the nature of the bike by positioning too much weight over the rear wheel. Changing the rear wheel size already changes the front to rear balance of the bike, even without altering the chainstay length.

We can look at the shift that downhill bikes underwent as they moved from dual 29" with relatively short chainstays, to mixed-wheeled configurations with chainstays that measure longer than their 29 counterparts. This long rear center and small rear wheel combo retains stability but allows the wheel to tip into corners easier.

photo
Commencal's Supreme V4 29 was built with short 430mm chainstays.
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When they introduced the mixed wheeled version, the chainstay length was stretched further (456mm at static - size MD) to increase stability.
photo

I recently had the opportunity to put that theory to the test by riding a yet-to-be released DH bike that used multiple flip-chips, one to switch between rear wheel sizes and another to alter the chainstay length. Not every bike can offer both of these flip-chips, though. That can be due to packaging constraints, added cost, negative attributes which influence the suspension kinematics linkages, or just the brands’ intended ride characteristics.

The Giant Reign and We Are One Arrival are two enduro bikes with medium to longer chain lengths (443 and 447mm, respectively) that can accept either rear wheel size without altering the geometry. During the review period of these bikes I had a chance to try back-to-back comparisons with both wheels. Although the geometry doesn’t change on paper, there is an inherent effect in which the smaller wheel makes the bike feel like it has a shorter chainstay already.

The larger diameter, and therefore heavier, rear wheel simply brings along greater forces, in both vertical and lateral directions, meaning It can kick you around when plunging straight down the hill and requires more leverage to initiate the bike into a turn. When you switch to the smaller wheel and a shorter chainstay, the effective center of mass changes dramatically.

What’s the answer then? After noting my qualitative changes between wheel sizes, bike brands who would like to offer two rear wheel sizes should consider two chainstay length options as well. A more sensible option would be to keep the chainstay length the same when swapping to a 27.5” rear wheel if you’re looking for a more playful bike, or better yet, make the chainstay even longer if you want to retain that stability.

Is that cheap, take less resources, or make bikes less complicated? Certainly not, but simply slapping a flip-chip in there for the sake of fitting both wheel sizes could be hindering the performance of your otherwise outstanding bike.

photo
Scott's downhill bike, the Gambler, can accept either rear wheel size and still has two chainstay lengths to choose from. I'd bet that most riders either have the 29" wheel in the short setting, or the 27.5" in the long position.


Author Info:
mattbeer avatar

Member since Mar 16, 2001
352 articles

183 Comments
  • 178 19
 "Mountain bikers love meddling with dials, spacers, air pressures"

Not this guy. Coil suspension, 11sp Drivetrain, No flip chips on my current bike and no intention to change any of that. The less time I have to spend messing with my bike the better.
  • 101 3
 Yeah, but having flip-chips does not mean you need to play with them. I think most people set them once or twice and then keep it in their preferred setup until they get another bike.
  • 12 1
 ideally you have lots of bikes then never have to adjust anything! I'd like a bike that can have some simple adjustability for bike park riding and then everything else. A steel hardtail must have SS compatibility, just cause.
  • 15 26
flag bishopsmike (Feb 8, 2024 at 12:23) (Below Threshold)
 Are you even a mountain biker then?
  • 15 2
 My favorite bike to ride is a hardtail with a coil fork and XT 11spd. It requires no thinking.
  • 35 2
 Bro 11spd is wayyy to complex, 10spd is where it is at
  • 7 1
 I like flip chips and adjustable angle headsets. I like options.
  • 9 0
 Coil is life!
  • 7 1
 I bought a Cane Creek DB thinking I was going to dial my suspension in perfect. Boy was I wrong… I kept it in the stock settings and didn’t touch a thing. It was so overwhelming and I never had the desire to mess with it. Learning moment for me.
  • 5 0
 @IluvRIDING: I put mine in low for park days and high for pedal days, though it's difficult to tell the difference to be fair.
  • 2 2
 Coil is real nice, but I'm curious the overall impression here. I had a coil on the trail bike and air on the park/DH bike. The coil does stick to the ground nicely, provides awesome traction and linear reliability, but the air is a must with the big hits at the park. All that aside and consideration "meddling", what happens if your weight and/or riding style don't match up with the spring your bike came with or you have at the moment? I found this to be too much to deal with. $70-100 each time I put on or dropped too many lbs rather than just adjusting air pressure... dunno. hard to say one is better than the other.

As for the opinion, I don't give a rat's patoody about flip chips and all that. The bike should work just how it is.
  • 4 0
 @IluvRIDING: yep, flipped one of mine once. Done fiddling.
  • 4 1
 My Fox Rhythm fork agrees with this statement 100%. Keep it simple and works great, minimal fiddling. Leaves me more time for bumbling down the trails.
  • 6 1
 @Roost66: f*ck yeah. I run a 10 speed Shimano 11-46 drivetrain on two of my hardtails and it rocks. One rear derailleur is part zee, part XT with a one-up rad r cage and several mm of aluminum filed off the shift arm for clearance. The other one I used a zee derailleur with a oneup radr cage and a wolf tooth goatlink 10. The best part is I can replace individual parts of each derailleur super easily from random trash derailleurs that come through the shop where I work.
  • 13 4
 @Roost66: Nah, brah. Gears are for … people with undeveloped quads. Single speed for life.
  • 6 1
 Exactly the same. This quote is basically only relevant to about 50% of people. The rest of us set our pressures and dials and leave them. 50% of the community is a lot of people. Frankly I dont care about mm measurements, I care if the bike rides the way I like it to. Biggest issue is the marketing hype train that influences designs (idlers, longer reach, higher stack etc). By now we should have been at a point where this is all settled, the fact it isnt makes me think its about selling you a new frame, not giving you the best bike for an average rider.
  • 2 1
 @bombdabass Nailed it!!!!
  • 4 2
 This is curious,
how does either an 11spd drivtrain, and coil suspension mean less futzing with your bike?
or the lack of a flip chip?
  • 3 2
 @flattoflat: riding your hardtail requires no thinking?
I'm gonna need some further details.
Riding my hardtail in any sort of aggressive terrain, or in an aggressive manner requires more mental capacity on my part. Its far more hectic, requires much more focus on the terrain further ahead, requires more precise line choice, requires a more dialed back ride on new or blind trails, just reqires more if I'm going to ride at a quick pace. If I'm just toodling around, sure, but it still doesnt make things less complicated.....
And I'm not sure how 11spd, or coils change any of that?
  • 6 2
 @Roost66: 9spd or nothing,
You guys are all so soft, I only ride 8spd

I've got a fully ridgid Stumpy, running 6spd friction shifting, and anything else is so over the top, you guys have no idea.....

Fack we are a weird bunch, what a strange flex!
  • 2 0
 @TheR: is that what you will tell your knees in a few more years?
  • 5 3
 @onawalk: Meh, I'm running a 40lb single speed with 50T chainring and 10T cog. Doing 10K vertical feet a day on it through snow.
  • 2 1
 @tacklingdummy: Friggin get after it!

Dont forget to tell all the "early adopters" that theyre sheep for buying into the SRAM marketing!

You shouldnt even be using clipless pedals, its rattraps or nothing at all!
  • 1 3
 I think most like the "illusion" of adjustability, but in reality dont ever change much.
I have a buddy with a Stumpy evo, loads of adjustability, hasnt tried it in the "low" mode of the setting as he said it would be too low. when I checked the online configurator, it was 1mm lower.....1mm.

Same buddy has splashed out on Fox Factory suspension, but did not know how to measure sag. Also never checks his sag, in fact of 20 buddies who all ride at a very high level, 3 of them would check sag prior to a ride. 5 of them hadnt checked sag all season....all riding expensive full sus mountain bikes
  • 2 0
 @getschwifty: Right there with ya! Still running 10 spd here with modified Saint derailleurs. Using the One Up RadR cage here as well. Hope jockeys thrown in for good measure. Since moving to that system haven’t broken a single derailleur in years. Broken derailleur used to be a regular occurrence. Wish One Up still made that Radr cage
  • 1 0
 Same here minus the coil suspension. I ride st 29ers.
  • 1 0
 @onawalk: Sorry, it was just a sarcastic joke.
  • 2 0
 @tacklingdummy: As was mine
  • 1 0
 @tacklingdummy: I guess neither of our comments were very funny if we needed to point out that they were jokes....
  • 1 0
 @onawalk: If said in person, it would have been obvious jokes. I laugh when I read both of our jokes, now. Lol.
  • 1 0
 @tacklingdummy: Nice,

I wish there was a universally acceptable "sarcasm font"

@brianpark, if you developed this, and made it available in the comment section ,i bet it would catch on around the world......
  • 51 4
 I don’t understand this anti adjustability approach. The whole „get it right from the beginning“ talk. Especially with geometry, in other things I agree but first back to the geometry topic. Let me elaborate my thoughts:

In my opinion it comes down to two topics as to why I think as much adjustability as possible is the way to go. Taste and physiology.

If you look at it from a distance and compare it to things we got used to it comes very clear to me why we should all be able to choose to fit both of the mentioned topics:

Example - Take out all of the adjustability from my car seat please and just get it right the first time. Or just give me 5 positions .As we all come in different size and shape 5 to 6 sizes in frames can’t possibly fit all the riders out there. Now some of you might say that there are handlebars, grips etc. to fix that problem they all have the same dramatic side affects if not more than adjustable geometry plus they don’t necessarily change what you are looking for plus you spend more money on buying parts to error what seems most comfortable for you.

Example for taste - ban all the salt shakers in restaurants and just make the cook get it right the first time. I think I don’t need to elaborate and with things like tyres, grips, airpressure in forks and tyres that we already got used to, we are very picky. Imagine there would be gas filled cartridges according to your weight in forks because the brand has to just get it right…

I totally understand the overwhelming frustration of all the adjustments on modern bikes which leads me to where I think companies should get things right the first time:
Lockout levers for example. Everyone who did some technical climbing knows that traction is key so in my opinion these lockout levers should go. Kinematics should not be designed around the option to lock the rear out. Don’t get me wrong, I appreciate a quickly accessible platform to give some more support but that’s not the same thing. Another example would be brake alignment. The number of bikes I see in the shop where the brakepads can’t use the whole surface due to poor tolerances is wild. @specailized I am talking to you. The list goes on with shock/waterborne compatibility etc. These are things where nobody profits from no matter your taste or physiology.

No one forces you to flip a chip or exchange a headset cup. Do you want to ride the stock setup, cool. That’s fine but why not have the option? Complexity? C‘mon…
And of course there’s that one guy who says „but you could mess the geo up and f*ck up the intended ridefeel but to come back to the car example, there are also guys who think they are faster with there seat rolled back all the way and closer to the ground. Idiocy should not be the reason to stop trying making bikes as fitted as possible.

Proof me wrong, I am happy to be convinced.
  • 12 3
 Would the adjustable car seat be more analogous to setting your bar height, stem length, and saddle height and not adjusting the bottom bracket height by 3 mm and the head and seat angles by 0.5°?
  • 6 3
 This right here needs more upvotes.
  • 8 1
 @pmhobson: I agree that theese 0.3 degree or 5mm adjustment are difficult since the average rider won’t notice, maybe not even a pro…who am I to tell.
Sure you could say that the car seat is more analogous to bar highs etc. but what I wanted to make clear that there we are very pleased to have a infinitely variable in x and y axes, same goes for the steering wheel in cars and even then people buy bigger, burlier or different material steering wheels. My point is, who is hurt by geometry adjustment?
  • 5 0
 @DorianKane: I can definitely feel the difference on my Stumpjumper Evo between various settings, especially changing the head angle.

To return to your original point, prior to my SJE the flip chip on my previous bike didn’t make that much difference, whereas on my SJE having it set up correctly for the riding that I’m doing has a significant impact on my enjoyment.
  • 3 0
 I'm with you. I like to tinker and i like options. I would assume the companies ship the bike in the neutral settings so people that will never adjust it have a great riding bike. The adjustments are there for the people that want to tinker.
  • 8 0
 *Adjustable HA / Reach combination headset cups
*Adjustable CS length
*Adjustable Shock Progression chip (Not a flip chip that changes BB / HA )
*Optional Links to run a Mullet or 29 ( Sold on Mfg website for those that want it)
*External cable routing (mainly for brake line)
*Size specific CS lengths
*Shorter Cranks 155mm-170MM (to correlate with frame sizes and suspension travel)
*Threaded BB
*Generous TT Length ( but not too long)
*76-78.5 deg. STA ( to correlate with size frame)
*Dropper insertion clearance for longer post (all frame sizes)
*Water bottle mount for standard size bottle
*NO HEADSET/ HANDLEBAR / STEM CABLE ROUTING OR INTERNAL SHOCK FRAMES !!!!
  • 5 0
 I’m gonna have to agree with you here. The one size fits all approach doesn’t work. Neither does the marketing approach of making everyone feel that last years bike is now simply a dinosaur and absolutely unusable. That’s complete bunk and people fall for it. Some things are indeed game changing. Take dropper posts for instance. But we all know which things are and which things aren’t. This article primarily deals with two issues that are fundamental to a bike’s handling. That is wheel size and wheel base. The whole notion of “getting it right the first time” is ludicrous. I happen to be fortunate enough to have a mini mountain bike museum in my garage. All the bikes are rideable and still ridden. I’ve got bikes from 1999 up to 2022. Guess what???? There’s nothing wrong with any of them. I’ve updated all of them with droppers, modern brakes, better shocks and more reliable drivetrains of course. Do they handle differently than one another? Absolutely! My 17 yo son’s favorite bike is his 2008 Intense 5.5. He calls it “the greatest trail bike of all time” It’s got 26” wheels a steeper head angle than anything built today and short chain stays. He likes it because it’s like riding a full suspension BMX bike through the woods. He can throw it around all day long. But…. He also knows it lacks the stability of his Tracer from 2 years ago. His bike handling skills are due to the fact that he had to learn perfect jumping technique riding that 5.5 due to its geometry. Same with his technical riding skills. Take that old short bike down a DH course and you learn very quickly how to dance on the edge of Newton’s razor. Those skills translate into the bigger more stable bikes but not the other way around. You just need more muscle to get them to corner, hop, etc. I would argue that the great wheel size revolution and many of the geometry changes have indeed resulted in greater stability and safety but not in better handling bikes. This is good for pros that already have great bike skills because it allows them to go faster. Ditto for the brand new rider because mistakes are more easily forgiven at the expense of pop and fun. Essentially longer stays and wheelbases along with 29” wheels maximum the inertial tendency of the bike therefore increasing the plow through it factor. Basically we’re trading in fighter planes for bombers. So I’m all for adjustments in chain stays and wheel sizes. Just wait until the market runs out of ideas and starts marketing a new wheel size as being fun and manouverable. That new size will be 26”! It’s all just different flavors not right or wrong. Everyone’s body size and flexibility is different. Bikes should be able to adjust to the rider’s style and bio mechanics.
  • 1 0
 @fattyheadshok: if all of your bikes from 1999 to 2022 are still rideable and fun, why do they need to be adjusted by the amounts current flip chips let us adjust geometry?
  • 2 0
 Considering I have seen riders on old bikes completely destroy trails I am of the belief it is the rider, not the bike as the industry would have you believe. Most cannot properly set up a rear shock...... I believe the current geo is peaked and cannot get better. 64 HTA and 75 STA is to me sacrosanct and cannot be bettered.
  • 2 0
 You are my new guru!
To me the difference is- why do you ride? I’m an ex Moto racer for most of my life, and I’m racing the clock when pointed downhill. It’s all I see, and I don’t care who sees me.
I picked up a Trust Message fork for my Tallboy, and was determined to cure the infamous harsh ride. And I did.. It took a lot experimentation, but I found a hidden sweet spot in a psi and unorthodox light rebound setting.
Now I don’t have to talk shit about that fork and throw it out for something else.
Was still just grade school arithmetic that got me there..
  • 1 0
 @pmhobson: you are on the right track but stopped to early.

For example, I have shoes size 13.
If I ride a 26” dirt jump bike my heels and therefore my weight is way back behind the rear axle. Rides strange, more like a unicycle than my beloved trail slayer.

That’s a completely different riding experience compared to someone with size 9shoes for example.

Addressing this issue with Frame sizing isn’t a perfect solution either as for example short riders sill could have massive feet…
  • 1 0
 @michibretz: are you saying that adjustable geometry addresses issues that arise from different foot sizes?
  • 1 0
 @pmhobson:
Umm, I went from XC style clipless to clipless platforms, and it allowed me to experiment with more fore/aft foot positions on the pedals.
I’m now about 10mm “back” from what I had to run for support on the full race XC baby pedals.
That’s 10mm more reach, and it’s put my weight further forward where I never knew I needed to be! Feels much more natural.
Size 11 feet.
  • 1 0
 @Untgrad: hopefully you traded the XC shoes for AM shoes that mate to the pedal platform as well.
  • 1 0
 @likeittacky:
That came first.
Riding is a pleasure compared to my roadie in the woods set up!
  • 2 0
 @Untgrad: welcome to the party!
  • 2 0
 @likeittacky:
..thank you!
IDK where I got the idea that Mtn biking was “XC based”.
I got into it around year 2000, and I guess that’s all I saw.
Coming from Moto racing, I assumed a certain amount of suckitude because it’s bicycles..
24 years later, things are different, and it’s all good!
  • 51 6
 I despise meddling with dials, spacers, air pressures on a mountain bike and I've been riding for 35 years. I have to meddle with stuff all day long at work. When I get on my bike I just want to ride.
  • 32 0
 My bike shop loves how much I hate working on my bike.
  • 4 1
 I’m 35 years old and I’ve been meddling on bikes in my sleep for about 70 years now… only recently have I come to find my happy medium and relative center.. so now, I don't need to touch a dam thing! Lol - jokes aside, when it’s right it’s just right! Not much needed more than the riders ability
  • 1 10
flag valrock (Feb 9, 2024 at 8:36) (Below Threshold)
 ok grandpa, now, lets get your pills
  • 30 1
 Nicolai G1.
Have your cake and eat it.
You can have any wheel arrangement and independent geometry changes. On a bike that is 5 years old and still current.
And they're just about indestructible to boot(er)
  • 12 5
 Not to mention 10 years of spare parts availability promised by a company that's been around for three decades, if you keep bikes a while.

You may also get warm fuzzies from not supporting communist factories in China/Vietnam if that's a thing you care about.
  • 2 0
 .....any wheel arrangement?
  • 1 0
 @j-t-g: yup, change the wheel and the appropriate “mutators” and crack on
  • 1 0
 Same frame and never did anything lol
  • 10 0
 Coming up to 5 years on mine, damn thing won't break. It's satisfied all my curiosities over the years. I've run it mullet, I've run it full 29, I've run it full 27.5, I've run it with dual crown forks, I've run it in its lowest and slackest setting, I've run it with a higher BB and steeper head angle, I've run it with longer chain stays, I've run it with shorter chain stays. If I want to try the new Sram 'transmission' I can if I was prepared to pay the ££££'s. Sometimes I've left it in the same configuration for the best part of a year, sometimes I bounce between different set ups week after week.

I feel like I am having my cake and eating it, the only problem is I have to keep swapping to firmer springs Redface
  • 2 0
 @smatkins1: Same. Every itch I've ever wanted to scratch, I've been able to on one frame. It will outlast me, that's for sure
  • 1 0
 @mashrv1: 20 inch bmx front, 32 inch rear
  • 1 0
 Except that you have to put up with Nicolai‘s ridiculous geometry, where no size has enough stack height but even a medium is too long for most riders.
  • 1 0
 @Muscovir: they'll make you any geometry you want for a modest custom fee and it'll still cost less than a communist plastic frame. My Nic has a 670mm stack.

Also look at their geo charts carefully, the listed stack is often based on a shorter fork A2C than most would choose with any given frame. Most would run a 170mm fork (~585mm A2C) with a G1 but the chart specs 567mm.
  • 46 15
 The shorter the better...
  • 52 2
 That's what sh... nope
  • 8 9
 There's got to be a limit... I'm assuming you're a Spesh Status owner who thinks the stays are way too long?
  • 4 11
flag Jordmackay (Feb 9, 2024 at 2:11) (Below Threshold)
 You are clearly someone who is below the height requirement for high value woman
  • 7 4
 Bring back 420mm chain stays
  • 5 2
 @nfontanella: combined with 69 degree head angles...right?...
  • 3 1
 I second the return to 420mm chain stays, even at 6'7.
  • 2 0
 @jonathanreid9: no the best bike I've ever owned was a kona process 167 with a dual crown I'd pay unreasonable amounts of money for another one
  • 19 0
 Ok ... yes, bmx background. From that I am very aware of making my backend longer or shorter for different things. Big trails or track, long backend, doing tricks, slower speed manuals, etc ... short backend. I actually would love to have adjustment on that part of the bike ... and on bikes like my slopeduro and short travel trail bike ... even my DH bike, I wouldn't mind having a bit shorter backend. For something I'm riding on fast and steep terrain, I'd like longer. So yes, I would like to see adjustment in that area. It totally makes sense for people that key into the benefits. ANd if you don't, just stay with the factory settings.
  • 9 0
 You pretty much took the words right out of my mouth. I’d love adjustable chainstays, but I generally always want a shorter chainstay on mountain bikes. I used to feel this way on BMX bikes, but I feel that they might actually have gotten too short over there.
  • 3 0
 Yeah. I too have a BMX background spanning into the mid 80's. I still love to manual. I still run a fat front and narrower rear tire, for turn in feel. I don't mind relying on my front tire and a little body English for a short rear. I only ride hardtails. My 26ers, you could manual anywhere. My 1st two 29ers, 430 and 435mm CS, still fairly simple. 3rd 29er, 440mm CS, gets sketchy, but has a 3" longer wheelbase. Newest bike has 444mm chainstays and is 3" longer then the other bike and 6.25" longer then the my 1st two 29ers. It's a bear to lift it on the flat. Man what I wouldn't do for a 425-430mm CS
  • 3 0
 @oldschool43: I feel that. I went for a status due to the short chainstays and still feel like I have to lean into an adjacent county to get into a manual, but in comparison, my bmx bike has a 333 rear end and feels almost too twitchy
  • 22 4
 I ride a bike because of the way it handles in the same way I go to a great restaurant because they serve amazing food. I don't go to restaurants where you make your own dish or choose items to put together. I want the bike brand to have designed and built a great handling bike... It's not my job to figure it out!
  • 5 0
 They typically design a bike suited for their trails they ride and areas they are located. So, the bike you buy may not be best suited for your riding. We tend to look at geometry and aesthetics only when buying a bike.
People like Jeff Kendall -Weed or other YouTubers will point this out when testing different bikes. With that being said, any given bike may not necessarily be fitting for you and your trails, thus leaving you vexed with the company and their design philosophy. Too add, your particular body mechanics and abilities will render different input / output on any bike design; One may rip on a certain brand and model while the other may struggle or be less confident on that same bike.
  • 15 1
 I think the next Grim Donut should be designed around all the bro numbers, 420mm chainstays, 69* seat tube, 66.6* head angle, etc.
  • 32 3
 Evil basically does that already.
  • 4 3
 @Glenngineer: They basically don't
  • 3 0
 Where is Levy when we need him... the Donut is all the UFO anyone ever needs.
  • 2 2
 @Glenngineer: Not even close
  • 11 0
 After dialing in the bike for your terrain, the most valuable adjustments are the ones that convert to/from park mode in less than 1 beer's time.
  • 5 0
 @chrod: the problem with that is after 1 I kinda feel like another then once 5 or 6 in I seem to loose track of what I was supposed to be doing.
  • 5 0
 @p0rtal00: one is plenty, two aren’t enough.
  • 5 0
 @p0rtal00: that's why the single beer time limit is so critical
  • 7 0
 I'd heard for a few years mulleting a 29'er is not recommended vs. adding a 29 front fork to a 27 bike (assuming non MX setup). Knowing I'm not "supposed to" do this, I bought a 27 rear wheel for a 2019 YT Capra and it totally shreds on the chainstay meant for a 29. I'd been running a 180 fork up front (stock was 160) for a couple years before adding the 27 rear.

For general trails (western NC) I mostly use 29 rear, but on the 27 climbing is just barely slower. It doesn't really feel any worse tho. But park riding is waaaaaay more fun w/ the rear 27, and the difference is palpable, esp w/ running Cush in the 27. I like getting faster times, and in doing lots of testing with this, I still continue to get faster times on either 29 or 27 rear - the main difference is just the more playful feeling on rear 27.

It's just bikes. Play around and you'll find things you don't expect. Often you don't find anything better or noticable and sometimes it's obviously worse but to actually know the differences you have to take it to different places to actually know. Effing around is not required either.... just like what you like - no one really gives a shit. Its your own choice. The point is just to play, cipher, & have fun on a bike.
  • 3 0
 ^^this...If you just throw a 27.5 rear wheel in a Medium Yeti SB160 you have a bike with a 630mm stack, 76 degree STA, 63ish HTA, a 337 BB height (that's not unreasonable, look at WR1, RAAW) with 439mm stays. As soon as the snow melts, I'm on it, sounds fun as hell.
  • 2 0
 @crgcrmny: I dunno the BB height for yr bike or if ya have a flip chip (Capra has one) and I measured BB in full 29 hi & low and to my surprise the BB (w/ 180 fork) mullet setup in hi position is only 2mm lower than the bike in in low position with 29s front & rear - so theres not actually a compromise... and fun as hell!

Ive been guilty of saying reach, BB heights, stack, chainstays, rise & spacer heights (etc) have to be certain numbers but then making changes (esp in park conditions w/ lots of runs) - you can get used to almost anything, and find awesome new ways to tweak a bike.
  • 9 1
 I fully agree with this. I like the mullet rear end, but also want a FC/RC that's as balanced as a full 29er.
  • 10 1
 I too don't want a super short chainstay with the smaller rear wheel.
  • 2 0
 Agreed. E.g. Was a bit disappointed when the Bird AM came out, looked great until I noted that the CS length drops from 440 to 429mm when you change to a mullet setup
  • 3 0
 I remember Santa Cruz arguing more or less the same way as @mattbeer in this article, when pointing out that their mullet had longer CS than the 29er (bronson vs hightower?!)
  • 1 0
 @mashrv1: That aeris am is a bike I'm quite interested in, but yes, 429cs with the mullet kills it for me me.
  • 3 0
 @moerkster: Yes that’s a great example with Santa Cruz’s lineup; Megatower vs. Nomad, Hightower vs. Bronson, etc. - and reiterates the point of the complexities in adjusting chainstay lengths on dual link bikes.
  • 9 0
 I think we should do away with chainstays entirely
  • 1 0
 Brought to MTB from road riding. Gotta be wrong
  • 2 0
 In fact, they only still have them on road bikes because of the UCI
  • 4 1
 By the same token, you don't always need a flip chip or angleset to run a mullet on a longer, well balanced 29er, depending on the geo that you start with. Example: I run a 160/160 Cotic RocketMax Gen 4 mullet on steeps and park stuff. It knocks the HTA back from 64.1 to 63.2. I just need to lower my fork pressure by 3 psi and the bike is perfectly balanced at the same sag points. The BB height drops to 332mm, but that's fine for DH trails with 165 mm cranks. Cy said it would be fine and it's been great so far.
  • 3 0
 I truly enjoy reading as much information as possible regarding the theory/physics behind each setting, but then I get frustrated when I am incapable of feeling the differences or decide which I like better on the trail (partially because of lack of time to try everything out and my general inaptitude).

So I am more than ok with a bike with little adjustments. Just ride it and love it, because in the end it is your bike and you will love just because of that.
  • 5 0
 That should read "Mountain bikers have been conditioned to think they need to love meddling with dials, spacers, air pressures, …"
  • 2 0
 People overthink the shit out of everything. Unless you're racing WCDH just set it up to feel o.k. and ride your bike. I've gone through bunches of bikes from hardtails to super fancy carbon everything with pro level suspension.

While I'm older now I'm on a "budget" enduro bike with mid-tier "set it and forget it" suspension (Marzocchi) and I'm way faster/ better than I was in the past. IMHO it's 90% your skillset not the bike and the setup.
  • 2 0
 Nothing is wrong with adjustability. Bikes like car drivers seat, build to fit EVERYONE, but people who are short, or long are always struggle. Give me all the adjustability there is, I will play with it if I want to. IT WILL make your ride better, but you do not need to touch it if you do not want to. Adjustability is the closes you get to custom fit without spending a fortune for custom made bike. Not even talking about barely any custom full squish, those that exist are only metal and no carbon option.
  • 5 1
 Short and thick does the trick and produces lots of different types of chainstays or is it babies? =)
  • 1 0
 I recently popped a 27.5 inch booty wheel in my 29 inch Vitus Escarpe, flipped the chip so its in the high setting as the bb was a bit too low. Now it rides sooo much better, does loook kinda weird but is planted af and way easier to manoeuvre, only downside is climbing is a bit slower, but i'm not winning any races period let alone up the hill.
  • 1 0
 I built up a Sommet like that, and I'm not sure I ever want to put a 29" wheel in the back. I got the 29" frame on purpose too just to mullet it because 435 is just too short.
  • 1 0
 My old-geometry 2014 Fuel ex 29er had a very short reach, looooooooong stem. Mega-steep head 69.5 angle and 455mm chainstays.

It felt longer at the back than the front. It was unbalanced and scary when descending steep stuff.

Current 29er hardtail has nice short 430mm chainstay, long reach, 66 head angle. Simple. Very balanced.

I am not one of these riders who likes to "meddle with dials". My bike has a fork that is set perfectly and a dropper that goes up and down.

It. Just. Works.
  • 3 0
 I generally don’t mess with my flip chips much either. I set the left in the high setting and the right and the low setting and then I have the best of both worlds.
  • 2 1
 Although left handed berms are a problem? #notanambiturner
  • 1 0
 When looking at questions like
1) wheel size / mixed wheel size
2) adjustable geometry / chainstay length, modular or adjustable dropouts, flip chips, head angle chips

We feel the “optimal” setup is often subjective to what the rider wants and where/how the bike is going to be riden
The “optimal” setup is reached by considering all the adjustments and options at once to understand how they harmonize

In general we feel bikes with adjustable geo options are a “win” for the consumers because they benefit more types of rider needs - we also think the adjustable bikes can often stay relevant longer because they adapt to new trends in suspension, geo, and parts easier - this offers some level of “ future-proofing”

\m/
  • 2 0
 Totally agree and have done similar experiments with short, medium and long chainstays for both rear wheel sizes. Mullet allows you to keep a medium to long chainstay and have both flick-ability and stability.
  • 1 0
 I think high/low flip chips are gimmicks, my last 2 bikes had them and instead of "high/low" they should have said "wrong/right" because the bikes only felt right in one setting with the other ruining the bike.

But I really want my next bike to have an adjustable headset and chainstay so I can dial in the FIT. Medium on my frame is too short, large is slightly too long, if I could reduce reach by 10mm on the large it would fit perfect. Then I would probably want to adjust the chainstay to keep the balance.

Bike makers cannot account for every body type with S/M/L/XL but they can make it easier for riders to get the right fit using adjustable headsets and chainstays.
  • 1 0
 @mattbeer this is an interesting article! I’ve got a We Are One arrival with the original chainstay (no flip chips). If I wanted to mullet the bike, should I just keep what I have vs buying the new adjustable chain stay? Curious on your thoughts
  • 2 0
 @jaydubmah Cheers, I’m glad you enjoyed it. Your best bet is to talk with We Are One for options, but I don’t believe it’s advisable to fit a 27.5” wheel to the non-MX version of the Arrival.
  • 1 0
 “Changing the rear wheel size already changes the front to rear balance of the bike, even without altering the chainstay length.”

I don’t know about this… unless you’re simply referring to a tiny bit less weight in the rear wheel and tire. But the balance of the bike as your ride it should stay the same as long as the contact patches and bottom bracket are all in the same spot relative to each other, right?
  • 3 0
 @TakeADeepBrett I wouldn’t have believed it either unless I had tried it, but I found the same characteristics on the Reign and Arrival, as mentioned. Both bikes state that the geometry is nearly identical when changing just the wheel. On the trail though, there’s clearly more at play here.
  • 2 0
 @mattbeer: My unsubstantiated theory is that gyroscopic effect of (both) wheels provides a feeling of stability - so the bigger/heavier the wheel, even if going the same linear speed (slower rotational speed), will be greater. Assuming this is true(!), then the larger the wheel, the smaller the RC makes sense. FC is harder to articulate as the 'feeling' will have a heap of other variables thrown into the mix.
  • 1 0
 Just so I understand... is Matt saying that the WA1 Arrival's approach of NOT shortening the chainstay length is the better approach to a flip chip which does? Just curious as I have a 170 arrival with the flip chip and currently mulleted... which I quite enjoy. Cheers.
  • 1 0
 I finally got around to changing the reach on my Strive the other day. I was skeptical that I'd feel anything. But actually 5mm made a noticable difference. 480 down to 475 was better for turning tight corners with more front end grip. At the slight cost of high speed stability. Guessing it's more to do with the difference in front/rear center ratios than actual length.
Crazy
  • 1 0
 Totally agree.

I'm running my S4 Stumpjumper Evo mullet (WRP yoke) but have fitted the seatstay from an S5 siE, this lengthens the chainstay from 438 (neutral head angle, high BB) to 448m.

The increase in stability that the longer chainstay offers is appreciated and allows me to keep a good amount of weight on the front for flat corners whilst maintaining a generous stack height for steeper trails, the long CS also allows me to run a shorter stem to maintain good leverage over the bike for manuals.

I've tried all of the geo settings plus both wheel sizes with the wrp yoke and specialized mullet linkage and this is by far the best all round setting.

Bike companies should start designing and marketing their bikes around front to rear center ratio, a ratio of 1.79 to 1.8 feels great to me, this can be achieved by running the Atunly in the steep head angle (65) and long chainstay (447) brining the front wheel closer and moving the rear wheel away the rider is more in the middle of the bike, it corners so nicely on flat turns here, very intuitively with a sensation of the bike pivoting around you.
  • 16 16
 Most importantly, all bikes should have as many flip-chips as possible. It adds very little weight and gives you an option to adjust your geometry or shock progressivnes or stroke to your taste. For instance I like slightly higher BBs and ride slightly more sagged then stock bikes are. And I like to play with the rear end length depending on how I wan't to ride.. With flip-chips in the right places you don't have to chose the bikes in stock geometry so you have more to pick from.
  • 31 20
 "all bikes should have as many flip-chips as possible"

Please no. Please?

Just get the geometry right on the first try.
  • 17 2
 @pmhobson: some autonomy to cater to different riding styles and differing terrain is always nice
  • 8 9
 @dillumbop: In my mind, that’s what different bikes are for.
  • 11 1
 I agree with this as long as they are notable changes. Having a flip chip that goes from 64.2° to 64.6° or changes rear center by 5 millimeters is pointless. Make them usable!!
  • 4 0
 @pmhobson: Agreed, if both bikes see equal use.
But for those of us who'd like to own one bike that can morph for a handful of special rides per year, flip chips make a lot of sense.
  • 6 0
 @pmhobson: there is no "right" geometry.

there are many "wrong" geometries however
  • 8 3
 More chips is asking for creeky hardware. Stumpjumper Evo's are notoriously not quiet.
  • 1 0
 @alienator064: haha. so true
  • 4 0
 I want a water bottle cage flip chip for those really steep downhills.
  • 3 2
 My ³22 stumpy evo in the last year is quite like a church mouse.. evo goodness
  • 2 0
 @troydevinci: mine too. Just the headset cups need regular greasing.
  • 3 0
 I ride an Altitude .. mixed wheel .. prefer the long chainstay setting.. 448mm anyway..
  • 1 0
 Also an Altitude, also mixed wheel, but it's a 2018 set up mini-mullet... 425mm chainstay, and it felt like it lost 10mm when I put the 26" wheel on. It's a riot of a play bike, but I can see why it's not for everyone. The standard setup was better for going fast and that's not even nearly as speed oriented as your bike.
  • 3 0
 Heu… is the last caption right? I have no clue but I’d bet the opposite.
  • 3 0
 Agreed. Jam those 29" wheels in those 400mm chainstays, no need to stretch them just because the wheels are big.
  • 1 0
 Reeb offers 410 mm CS on their REDIKYELOUS with 29*2.5 clearance so it can almost be done
  • 1 0
 I mulleted a v1 sentinel by running a longer shock and kept the same chainstay length, man that thing was a weapon. In hindsight I liked it more than the latest patrol offering from Transition.
  • 4 0
 Just bring extra chainstays in your backpack. Much easier.
  • 4 0
 I like short chainstays and I cannot lie. Small wheels too
  • 3 0
 Companies need to stop releasing XL bikes with 500 or more reach with a CS below 445. Anything less is just out of balance
  • 1 0
 FWIW the chainstay length on a medium 170 arrival is already fairly long at 447. Should be the same regardless of wheel choice? It's just not even longer than the full 29er like the mixed wheel supreme he's chatting about.
  • 3 0
 (Paul Aston) ‘hold my beer…’
  • 3 1
 Just built up an Mx Spire, the longer stays was one of the big reasons I picked it over the Patrol.
  • 3 1
 The MX Spire is such a fun bike. I’m surprised TR stopped advertising it as mixed-wheel compatible. I’ve got a angelset on mine to keep the head angle in check, but aside from that, the geo is dialed.
  • 3 0
 @dlxah: Sweet! Haven't been able to ride it yet with the weather. I used the Cascade Components DHX2 Mx link to correct the geo.
  • 1 0
 @dlxah: Are you running a +1 or more? Thinking about the same. I have already dropped a +1 in mine and really like the way it handles compared to stock. Thinking maybe I need a 1.5 or 2 if I go mullet.
  • 1 0
 @basken: I’m running a +2. That puts the head angle around 64 in the high position. The mixed wheels slacken it by about 1 degree, so you’d probably like the +2.
  • 1 1
 I think one of the main reasons that chainstays feel shorter on mullet bikes is that the rear axle winds up lower than the rear axle, changing the weight balance between the wheels.
  • 4 0
 Erm, what??
  • 2 0
 @sargey2003: doh, lack of sleep. The rear axle ends up lower than the FRONT axle, changing the weight distribution.
  • 1 0
 @djjohnr: also, often the initial bit of travel is slightly rearward. So of the flip chip moves the rear triangle down via the suspension linkage (ex with a flip chip at the shock mount), you will end up with a shorter rear center.

Then as you said the front will feel lighter with a smaller rear wheel even if geo is fully preserved. For someone who likes the long rear center feel this is sort of a lose lose
  • 1 0
 With a lot of 4-bar-chain designs (Horst link), shortening the chainstay with a flip-chip pushes the BB up a bit partly "correcting" for the change in wheel size.
  • 1 0
 I don't know about the Gambler, but my Sender has dual 29" wheels and the rear wheel is in the longer chainstay position where I really like it.
  • 1 0
 In perfect world I’d have a bike with all the adjustments possible. And then I’d have a single speed rigid bike to ride off the stress of meddling with the fancy bike.
  • 1 0
 They could have left fork offsets alone, too. Long fork offset with steeper hta can be equal to a short offset with slacker hta.
  • 1 0
 I dunno, it’s such a small adjustment does it really do anything? To me it just seems like a sales marketing duck cleaning service.
  • 1 0
 I was wondering about the comment of having two chainstay options.
If there were two options wouldn't the seatstays have to be changed as well?
  • 9 8
 Fk short chainstsys takes away grip from the front wheel 440-450 cs mullet
  • 5 9
flag englertracing (Feb 8, 2024 at 12:43) (Below Threshold)
 You get it! Slowpokes eat up and perpetuate that short stay bikes turn better. Its bullshit.
  • 5 12
flag HeatedRotor (Feb 8, 2024 at 14:56) (Below Threshold)
 It doesnt really, If you know how to ride, Short CS is better. Learn to weight your bike correctly.
  • 4 1
 @HeatedRotor: it really dies.. but hey glad your expressing your opinion
  • 2 0
 "Does"
  • 2 0
 Give me 450mm chainstays.
  • 2 0
 The correct length, I agree Wink
  • 1 0
 Now hear me out! Imagine riding the 29er scott with the longer flip chip option! Boom anarchy!
  • 1 0
 Imagine you had a suspension that was tuned for an average rider and gave you no options - stupid, isn't it
  • 2 0
 Can we take a moment to appreciate what an ugly bike the v4 was
  • 1 0
 275 bike with 430 stays and low stack for me thank you - industry hates me though.
  • 5 4
 Are we still talking about this in 2024?
  • 2 2
 I bet 95% of riders couldn’t tell between wheel sizes on the same chain stay length unless they buzz their butt
  • 1 0
 Durr, my DJ has shorter chain stays than my race bmx
  • 2 2
 regaurdless of wheel OR frame size...
short as possible plez (BMX back ground)
  • 1 0
 Dam you guys really don’t like the adjustments? I do lol
  • 3 3
 Pick a ____ and be a dick about it.
  • 5 0
 Nose?
  • 1 0
 @pipm1: just don't use the latter to pick your nose
  • 1 1
 ....
  • 2 1
 'name like richard'
  • 3 0
 Pick a dick and be ___ about it. Lol
  • 1 0
 Awesome Insight
  • 1 0
 Hardtail = no headache







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