What is the purpose of asymmetrical chain stays?

ctrlaltdel

I've noticed this on both full sussers and hardtails. Other than the fact that it looks kinda cool, is there any practical reason for the asymmetrical design?

myopic

To cope with the differences on the two sides of the bike! One side has to accommodate the drive train, primarily the rings from the chain set, the other doesn't.

nicklouse

what do YOU mean by Asymmetrical? as I feel it is not what others think it is.

so you can have a Zero dish wheel is what one maker says. But i dont think that is what you are asking.

ctrlaltdel

http://www.surosa.co.uk/images/cube-ams-110-pro.jpg

This bike, for example - the right hand chainstay is noticeably lower than the left one.

nicklouse

that is not an asymmetrical design.

Asymmetrical design has the stays offset about the center line of the bike.

and a wheel from a bike with an asymmetrical design rear will be off center in a "normal" frame.

bikes with asymmetric rear ends are not common but Specialized have more than their fair share of them.

re bikes with chainstays at different heights, yep been around for years.

Daz555

OK back to what the OP meant with his post - why do some full bouncers have chainstays running at different angles?

nicklouse

to allow things to fit/work.

NatoED

It's to do with the different forces put onto the rear of the bike. The disc side usually set higher to cope with the torque forces , reduce the amount of brake dive by redirecting the lever forces fed through the rear swing arm when you put the brake on. . It's not very effective but does help with some designs like the older kona's

nicklouse

NatoED wrote:

It's to do with the different forces put onto the rear of the bike. The disc side usually set higher to cope with the torque forces , reduce the amount of brake dive by redirecting the lever forces fed through the rear swing arm when you put the brake on. . It's not very effective but does help with some designs like the older kona's

err what? how when the pivot is in the same place? shape has nothing to do with any of the above.

Anonymous

nicklouse wrote:

to allow things to fit/work.

Simple, concise, and accurate as always. Like a truth ninja

meesterbond

On road bikes (removing any influence of suspension or disc brakes), the rationale was always that with a chain only on one side, forces aren't applied equally around the frame... Pinarello explain it below. Whether or not, that still applies on a mountain bike or whether they're there for more practical purposes is I guess up for debate.

The Idea
The behavior of a bicycle frame is strongly asymmetric. While the forces applied to the pedals are approximately equal, the offset of the chain to the right side means that the forces acting on the frame are asymmetric.

The asymmetry of the Dogma 60.1 begins with the chainstays, but progresses through the remainder of the frame as well as the fork. The right chainstay is smaller at the front end (near the bottom bracket) and grows larger towards the rear (dropout). Conversely, the left chainstay is reinforced on its front end, which is a very high-stress area, and grows thinner toward the rear. The right seatstay is larger and stronger than the left to counteract the forces acting on the bottom bracket area. The lower left of the top tube is reinforced as well and the right fork blade is noticeably larger and more angular in shape than the left. These are the regions that were determined to undergo the most stress from the asymmetrical pedaling forces and have therefore been strengthened, while other areas have been lightened. This creates a bicycle that is more “balanced” than possible with conventional techniques.

Anonymous

Ever heard of marketing bullcrap? Almost all bikes have way too much of it.

Daz555

Chainside stay needs to be low to allow the chain to have space. Disc side might as well be high so at least you have a little bit more ground clearance under the stay. However, given that the brake disc and chainring are much lower anyway I'm not convinced it offers much at all.

So clearance might be a factor but not that critical.

I reckon it is down to wanting more stiffness. The asymetric chainstay setup will be stiffer than if they were both parallel. Having said that - why the need for more 'vertical' stiffness in a rear suss setup which moves in that plane anyway?

hard-rider

I noticed that some of the higher end Canyon bikes had different chainstays left and right. They said it was due to the different forces applied through them due to the drive forces through the drive train.

Bar Shaker

I also thought it was for chain clearance.

The left hand chain stay is at the optimum angle, the right hand side one is dropped for clearance and beefed up to counter pedalling forces from the cassette.

chiefgrooveguru

that is not an asymmetrical design.

If it isn't symmetric then by definition it's asymmetric.

ilovedirt

I've wondered this before myself, I think it looks pretty nasty.

supersonic

On my design, the offset is there so the front mech doesn't foul the stays when on the granny ring:

Daz555

supersonic wrote:

On my design, the offset is there so the front mech doesn't foul the stays when on the granny ring:

They could have made the the other side the same......

supersonic

Lol, indeed, I guess they think the more direct line is better...

Anonymous

doesn't look like there's a lot of mud clearance on the drive side there, Sonic!