In Defense Of Long Chainstays

[Unoveloce]

I'm gonna come right out and say it, I like "long" chainstays on my mountain bike. I'm tired of being sold a bill of goods that bikes with short stays climb better and get better traction. It's B.S. in the sizes of bikes I ride. At 6'4" the bike I'm on has the same length stays as a bike built for a person 5'4" and that's crap. I realize that in the mountain bike market that advertised chainstay length has replaced standover for the most meaningless and yet most scrutinized dimension on production bikes. Yes I could get a custom bike made, but there aren't many of those being done in full suspension. Those that do are buying rear ends from excellent suppliers like Ventana and those all come with the same length stays, regardless of size. I'll dig a little further into why I dislike short stays to explain my belief. Take a bike that's made for the average 5'10" guy and drop a plumb line down from the sit bone area of the seat and notice where it falls in relation to the contact patch. Probably somewhere just in front of or towards the front of the contact patch of the tire. Now lift the front of the bike to replicate a 10-20% climb and see where the plumb line falls in relation to the contact patch. In the smaller sizes, it's probably still within the contact patch. In the bigger sizes (and not as big as you'd think) when you drop the plumb line on level ground, it falls at best towards the back of the contact patch and quite often behind it. When the bike is pointed uphill, that point now falls further and further behind the contact patch, and it gets worse and worse the steeper the climb. Meaning every steep, loose climb is a delicate balance of resisting spinning out and looping the front end. The taller a rider is, the higher the center of gravity is and the more exaggerated this tendency is.

Now I understand all bicycle geometry is an exercise in compromise. Long chainstays have their own draw backs and I'm fully aware of them. I just get tired of hearing how shortening a mountainbike's chainstays is always a benefit and has virtually no downsides, especially when someone tries and spout the B.S. that they climb the steeps better. Ever look at a motor bike designed for hillclimbs? Sure they are an extreme, but look how silly long their swing are.

O.K. Rant over. Thanks guys. I look forward to hearing everyone else's take on this. Cheers.

[wcu]

I even like 43cm stays on a road bike...

[Peter Polack]

That was a very good observation. When I first started reading your post I disagreed, since I'm a short rider and remember my experience with my first mountain bike in 1984 with 18" long chainstays. But what you're saying makes sense. The question is, how would framebuilders quantify that problem so they would know how much to lengthen the offset from your mentioned plumb line to the rear contact patch as the rider gets taller. Next question would be, is this just important with mountain bikes or should road bikes be considered as well?

[Mark Kelly]

Went from 410 to 425 on my last bike. Liked it a lot. The one I'm building now will be 435 or 440.

I have a theory that reducing trail as the WB lengthens helps handling, I'm shooting for about 50mm on this one.

[pruckelshaus]

Yup, last frame I built (a 650b) had 415mm stays, the one I'm working on now will be around 430 (with long horizontal dropouts, no less!). Bikes were designed like that for decades, and for good reason...they went away when more people rode on "improved" roads, and anymore, those "improved" roads, aren't.

Super short stays, super steep head angles with too little trail, and all of that other stuff are just silly for most people IMO

[fortyfour]

What I would add to this conversation is that everything on a bicycle works in harmony and is intended to be an extension of the rider meant to enhance their experience and responsiveness for their preferred terrain. What works for one riders physicality may not work for another. It's the job of the builder to split these hairs to fine tune that ride experience for that rider. When I state "works in harmony" I'm speaking of not just chainstay length, but bottom bracket height, head tube angle, riders positioning between the both wheels, position of the saddle in space, etc. right down to tire pressure and tire choice which play a large role too. No one measurement or angle makes the bike. It's the entire group of measurements and angles that make the bike and their relationship between the rider and bicycle that make the ride / bike. The discussion starts with rider, preferred terrain, riding style, positioning on existing bikes, addressing any physical issues, drawbacks and shortcomings and then how they'd like their new bicycle to perform. The challenge is taking all this information and funneling it into their new bike. A series of compromises are surely to follow but it's the job of the builder to "separate the wheat from the chaff".

Mountain Bikes and cycling have come a long way since their inception. What is so amazing is that there are individual groups of riders with different styles, each pushing their own personal limits and what they want their bicycles to help them achieve. As builders we can be the very ones to help them achieve those next steps however large or small. I don't necessarily see "custom" as the pinnacle, but rather it's that next step in a riders life where they seek to get that little bit more of performance or harmony out of their bike, or perhaps realize a compromise they were previously ignoring or it's that one last step to get that much closer to their trail be it paved or unpaved.

[boots2000]

I would say that chainstay length is 1 parameter in the design equation.
Everything else has to be correct in the design. Specs and materials.
One thing that I have noticed as that with the advent of carbon, you can run longer stays and have the bike keep its racey feel.
The Trek Domane with 42cm stays does not feel long at all.

[omnigrid]

I'd guess differing CS stiffness is really whats going on.

[Willie1]

I have noticed a trend with shorter CS being countered by slacker HTA. Kids look at trail bikes and think they "need" a 67deg HTA or slacker, which is the current trend. I personally like 68 or 69 deg with mid length chainstays on a 5.5" trail bike. My DH has a 65deg HTA, and is a little slack. Current DH bikes are 62-64HTA. In the MTB world, it is all about advertised HT and CS.

[balindamood]

My '84 Trek 830 has 46 cm stays. Probably a bit much, but it runs down-hill like it is on rails.

[darkmother]

I'm on the taller end of the spectrum, and I agree with the OP. One of the things I like about 29er MTB's is that they force manufacturers to use a longer CS. Puts my center of mass more where it should be.