Brucey wrote:I can't say I'm surprised that Colin has got cheesed off with this; whether you can get cable of different types or not doesn't make much difference to 'spongyness' at any given MA, regardless of brake type.
Even if the cables did contribute most of the sponginess, the cable tension difference between Vs and cantis is only about 30%. This is to an extent countered by the fact that the V brake usually has a longer cable run than a canti.
In reality the reaction forces generated at the brake bosses and brake blocks are such that the greater part of any sponginess comes from the brake blocks squishing and the fork/stays flexing etc. These movements (at any given braking effort/MA) are identical whether it is a V or a canti. If you think otherwise, sorry, you are fooling yourself.
You can see that it is this (and not cable housing compression/cable stretch) quite easily, by looking at whether the cable moves (at the brake end) or not as you squeeze the lever. If it does move, it isn't the cable that is causing the spongyness.
BTW if you frame and fork don't flex, you probably have a very horrible frame, that is much stiffer than it needs to be.
cheers
Ok then, why is it when I used cantis on my mountain bike, a brake booster on the back brakes made a big difference. When I converted to V's, I no longer needed the brake booster. Could it be that, with the cantis, the twisting outwards of the chainstay mounts caused the straddle cable geometry to go all to hell whereas the V brakes were mostly immune to this geometry change?