Re: Curved seat stays

I believe the laterally curved seat stays originated with mountain
bikes, where they actually do have functional value:

Being wider at the top gives better tire clearance.

Being narrower where the cantilever brake pivots are is generally
desirable as far as the brake setup is concerned.

Translating this design to a bike with caliper or disc brakes, however
is the triumph of style over substance.

My Hetchins has longitudinally curved seatstays and chainstays, but I
like it despite that fact.

Sheldon "Likes Straight Tubes Except For Fork Blades" Brown
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Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
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Sheldon Brown said:

I believe the laterally curved seat stays originated with mountain
bikes, where they actually do have functional value:

Being wider at the top gives better tire clearance.

Being narrower where the cantilever brake pivots are is generally
desirable as far as the brake setup is concerned.

Not necessary, however, as it's easy enough to simply offset the
pivots on the tube so that they're closer to the wheel
centerline...as, in fact, was done on several frames I have. The
S-curve does permit them to be mounted more centrally on the stay
tube, but I don't see that this is a terribly compelling reason.
--
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I said:

Quoted message said:

I believe the laterally curved seat stays originated with mountain
bikes, where they actually do have functional value:

Being wider at the top gives better tire clearance.

Being narrower where the cantilever brake pivots are is generally
desirable as far as the brake setup is concerned.

Werehatrack said:

Not necessary, however, as it's easy enough to simply offset the
pivots on the tube so that they're closer to the wheel
centerline...as, in fact, was done on several frames I have. The
S-curve does permit them to be mounted more centrally on the stay
tube, but I don't see that this is a terribly compelling reason.

I never said that it was a "terribly compelling" reason, but some bikes
use very fat tires on very skinny rims, (not a good idea, but quite
common) and this is a way to make such setups work slightly better.

Rear canti studs do generally mount off center on the stays, but if the
stays are way far apart to clear super-fat tires, a bend like this can
greatly simplify cantlever brake setp.

It is by no means the only solution to this problem, but it's one that
does work.

Shimano's "parallel-push" V-Brakes are another solution.

Wide rims to match the wide tires are yet another.

Sheldon "Not Terribly Compelling" Brown
+------------------------------------------------------+
| It were not best that we should all think alike; |
| it is difference of opinion that makes horse-races. |
| -- Mark Twain |
+------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Sheldon Brown said:

Quoted message said:

Quoted message said:

I believe the laterally curved seat stays originated with mountain
bikes, where they actually do have functional value:
Being wider at the top gives better tire clearance.
Being narrower where the cantilever brake pivots are is generally
desirable as far as the brake setup is concerned.

Quoted message said:

I never said that it was a "terribly compelling" reason, but some

bikes

Quoted message said:

use very fat tires on very skinny rims, (not a good idea, but quite
common) and this is a way to make such setups work slightly better.

Rear canti studs do generally mount off center on the stays, but if

the

Quoted message said:

stays are way far apart to clear super-fat tires, a bend like this

can

Quoted message said:

greatly simplify cantlever brake setp.

Rick Hunter (http://www.huntercycles.com/mainpage.html) builds
cyclocross bikes with curved seat stays for greater tire clearance
for more or less this reason. Of course, cyclocross bikes tend to
run wide (ish) tires on road-width rims. And use cantilever brakes.
The stays on his bikes also look nice, and give a distinctive
appearance, which is not a bad thing for a custom or small-shop
framebuilder.

Ben