Roller cam brakes Bicycle brake

roller cam front brake.

roller cam brakes centre-pull cantilever brakes actuated cable pulling single two-sided sliding cam. (first , second-class lever designs exist; first-class common , described here.) each arm has cam follower. cam presses against follower forces arms apart. top of each arm moves outward, brake shoe below pivot forced inward against rim. there in favor of roller cam brake design. since cam controls rate of closure, clamping force can made non-linear pull. , since design can provide positive mechanical advantage, maximum clamping force can higher of other types of brakes. known being strong , controllable. on downside, require skill set , can complicate wheel changes. , require maintenance: u-brakes, pad wears strikes rim higher; unless re-adjusted can contact tyre s sidewall.

the roller cam design first developed charlie cunningham of wtb around 1982 , licensed suntour. roller cam brakes used on mountain bikes in 1980s , 1990s, mounted head tube , seat stays in standard locations, , below chain stays improved stiffness not protrude interfere crank. not unusual bicycle have single roller cam brake (or u-brake) combined type. still used on bmx , recumbent bicycles.

there 2 rare variants use roller cam principle. locations centre-pull inappropriate, side-pull toggle cam brake developed. first-class cantilever, uses single-sided sliding cam (the toggle) against 1 arm attached link other arm. cam presses against follower, force transmitted other arm via link. , suspension forks housing must terminate @ brake frame, side-pull sabre cam brake developed. in sabre cam design, cable end fixed , housing moves single-sided cam.