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Dual-Pivot Sidepull
The dual-pivot brake achieves both greater leverage and the ability to work with smaller pad-to-rim clearance by its improved centering, by using two pivot points to define a line of action about which its two arms are constrained to move equally, meaning they remain centered. This feature is essential in reducing the pad-to-rim clearance needed for a higher mechanical advantages of about 5.6:1.
Greater leverage also required compromise. The offset arm (the short one) sweeps its pad upward into the tire so that its pad position must be adjusted as it wears. Also, the brake cannot track a crooked wheel with, for instance, a broken spoke, and because it has a high ratio, it works poorly, if at all, when the quick release is accidentally left open. And finally, it runs out of hand lever travel 40% faster with pad wear than the former single pivot brake. Low pad clearance and narrow flange spacing of current rear wheels make this brake drag when climbing hills standing. In response, racers often climb with the rear quick release open... and on occasion, fail to close it after reaching the summit.
Part of the light feel of the dual-pivot brake arises from the lower (reverse) ratio of the caliper, whose springs do not exert as strong a return force on the cable. With this lower force, a return spring has been added to the hand lever to give the desired return force but with lower cable tension during free motion of the brake (before making contact with the rim). This makes the brake FEEL even more forceful than it is because it has such a light free motion.