Originally Posted by
Kapusta
If rim brakes COULD be set up with a higher leverage ratio, they would be. Why do you think that they are NOT set up higher ratio than they are?
The reason is that higher leverage would reduce the pad travel too much. THis is why canti levers do not work well with v-brakes: too much leverage results in not enough pad travel.
This is exactly the reason that companies messed around with "servo" levers like the old XT v-brake levers. Low leverage in the beginning of the lever pull to close the distance to the rim, then significantly higher leverage at the end where you want it. Some of the Shimano hydro disc setups do the same. EDIT: I see below you point out that even regular levers increase leverage throughout the stroke. This is true, and I would ask: why did they design them that way? But the levers I am talking about do it much more so.
How close you personally set your pads is not the point. The point is that disc and rim brakes are design with vastly different amount of pad travel needed.
Your argument falls apart when you consider the types of levers used. You can’t use a long pull lever on a short pull brake
because of the cable pull ratios. However, we don’t have different levers for hub mounted disc brakes...at least for mechanicals. Mountain bike disc brakes use the same levers as linear brakes and road bike discs use the same levers as short pull side pull calipers and cantilevers. No adjustment needs to be made for any differences in leverage...only cable pull.