Bicycle Mechanics - V-brake mountain lever on a standard road brake - works great!

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TurbineBlade
08-05-10, 01:21 PM
I just realized on my old single speed I am running linear-pull levers with standard, old weinmann road brakes! The levers are tektro, which I assumed were regular-pull levers until I just noticed they are actually linear-pull.....:eek:. We had a bunch at the shop after a big order, and I must have taken the wrong set.

Thing is, they stop terrific! Actually, it's some of the best braking on any of my bikes....great feel and power, which brings up a strange point: It's not supposed to be that way. I've read Sheldon's cantilever article, and every cantilever-geometry-related article out there.....so I'm well aware that these levers theoretically only pull half as hard, etc.

Anyone else had this experience, either accidentally or intentional? There's no way in hell I'm changing the set-up because it works so well. I'm not advocating that people do this, but damned if it doesn't work on this set-up.

I'd never even try doing the opposite, with v-brakes using standard levers.....


dabac
08-05-10, 01:45 PM
V-brake levers do pull less hard, for a given pull at the lever. But as with many things bike-related the performance curve is more of a gentle hump than a sharp peak, which allows many combos th work just fine despite not being theoretically ideal. If you have good hand strength, good pads, good rims - then I'm not the slightest surprised that the combo works. I've used the opposite thing several times, canti levers with v-brakes. And for the front brake that too works just fine.

Besides, not all levers are the same. I've worked on one bike that had a pair of intermediate pull levers, longer than regular cantis but shorter than Vs.

fietsbob
08-05-10, 01:52 PM
A V brake lever pulls more wire for a given amount of hand motion, the effort will be a bit higher .

The fulcrum of the simple lever in classical mechanics terms is further from the work being done with a Linear pull lever,
because the leverage at the brake caliper on the wheel end of the cable is High leverage.

http://en.wikipedia.org/wiki/Lever

so needs to have more cable pulled , than a lower leverage arm , like a cantilever.

V brake and a low profile cantilever is a type 2 lever, old style L shaped cantilever brake is a type 1 lever.
the above page describes the difference.


TurbineBlade
08-05-10, 03:35 PM
A V brake lever pulls more wire for a given amount of hand motion, the effort will be a bit higher .

The fulcrum of the simple lever in classical mechanics terms is further from the work being done with a Linear pull lever,
because the leverage at the brake caliper on the wheel end of the cable is High leverage.

http://en.wikipedia.org/wiki/Lever

so needs to have more cable pulled , than a lower leverage arm , like a cantilever.

V brake and a low profile cantilever is a type 2 lever, old style L shaped cantilever brake is a type 1 lever.
the above page describes the difference.Yeah man, I get that. I knew that someone would post a reply about the physics/geometry of brake mechanical advantage! I get that differing yoke angles on cantilevers and pad extension inward from the brake arms, etc. influence mechanical advantage.....etc.etc.etc. until we die.

My ONLY point is that in real life I have a situation that works extremely well, against conventional wisdom. Actually, cantilevers are involved in this situation - just linear pull levers and standard road brakes.

BCRider
08-05-10, 04:58 PM
Any specifics about how you set them up combined with the pad material type and specific type of alloy in the rims likely just all came together in all the best ways. Like you say, don't mess with it!

TurbineBlade
08-05-10, 05:08 PM
Any specifics about how you set them up combined with the pad material type and specific type of alloy in the rims likely just all came together in all the best ways. Like you say, don't mess with it!

Yeah, I actually have v-brake pads instead of the stock-type block pads, and the wheels are araya 27" alloy - the standard on old road bikes.

Brake levers are the cheap tektro mountain levers, black colored with the clamp that opens all the way (if you know what i'm talking about) made for linear pull.

Dunno..? Just a weird observation that I didn't really notice until just recently.

Greyryder
08-05-10, 06:28 PM
I'd never even try doing the opposite, with v-brakes using standard levers.....

I did that last year. I used a one finger caliper lever on a set of V-brakes. Stopping power was incredible, but I had no feel for the brakes. I had to concentrate to keep a light touch on the lever, and I had to feel what the bike was doing, to keep from locking my wheel. By the time I felt any resistance in the lever, the wheel was long since locked up.

I've since bought and installed a V-brake lever.