Cantilever brakes Bicycle brake

1 cantilever brakes

1.1 traditional cantilever brakes
1.2 v-brakes
1.3 roller cam brakes

cantilever brakes

the cantilever brake class of brake in each arm attached separate pivot point on 1 side of seat stay or fork. cantilever brakes dual-pivot. both first- , second-class lever designs exist; second-class far common. in second-class lever design, arm pivots below rim. brake shoe mounted above pivot , pressed against rim 2 arms drawn together. in first-class lever design, arm pivots above rim. brake shoe mounted below pivot , pressed against rim 2 arms forced apart.

low profile traditional cantilever brake.

due wider possible distance between mounts , pads, cantilever brakes preferred bicycles use wide tyres, such on mountain bikes. because arms move in designed arcs, brake shoe must adjustable in several planes. cantilever brake shoes notoriously difficult adjust. brake shoes of second-class cantilever brake wears, ride lower on rim. eventually, 1 may go underneath rim, brake not function.

there several brake types based on cantilever brake design: cantilever brakes , direct-pull brakes - both second class lever designs - , roller cam brakes , u-brakes - both first class lever designs.

traditional cantilever brakes

this type of brake pre-dates direct-pull brake. centre-pull cantilever design outwardly angled arm protruding on each side, cable stop on frame or fork terminate cable housing, , straddle cable between arms similar centre-pull caliper brakes. cable brake lever pulls upwards on straddle cable, causing brake arms rotate , inward squeezing rim between brake pads.

traditional cantilever brakes difficult adapt bicycle suspensions , protrude frame. accordingly, found on bicycles without suspension.

v-brakes

linear-pull brakes or direct-pull brakes , commonly referred shimano s trademark v-brakes , side-pull version of cantilever brakes , mount on same frame bosses. however, arms longer, cable housing attached 1 arm , cable other. cable pulls against housing arms drawn together. because housing enters vertically above 1 arm yet force must transmitted laterally between arms, flexible housing extended rigid tube 90° bend known noodle . noodle seats in stirrup attached arm. flexible bellows covers exposed cable.

since there no intervening mechanism between cable , arms, design called direct-pull . , since arms move same distance cable moves regard housing, design called linear-pull . term v-brake trademarked shimano , represents popular implementation of design.

v-brakes function suspension systems found on many mountain bikes because not require separate cable stop on frame or fork. because of higher mechanical advantage of v-brakes, require brake levers longer cable travel levers intended older types of brakes. mechanical (i.e. cable-actuated) disc brakes use same amount of cable travel v-brakes, except described being road specific. general rule, mechanical disc brakes so-called flat bar bicycles (chiefly mountain , hybrid bicycles) compatible v-brake levers, whereas mechanical disc brakes intended drop-bar bicycles compatible cable pull of older brake designs (cantilever, caliper, , u-brake).

poorly designed v-brakes can suffer sudden failure when noodle end pulls through metal stirrup, leaving wheel no braking power. although noodle can regarded service item , changed regularly, hole in stirrup may enlarge through wear. stirrup cannot replaced, quality v-brakes use durable metal stirrup.

mini v-brakes (or mini v s ) v-brakes shorter arms, typically between 8 , 9 centimeters. reduces required cable pull, making them compatible brake levers intended cantilever brakes. mini v-brakes retain advantages specific v-brakes such not requiring cable stops. on downside, shorter arms provide small tyre , wheel clearance , make less forgiving setup: can accommodate smaller tyre sizes compared cantilever brakes, may pose problems mounting fenders, can clogged more mud, , can make harder change wheels.

roller cam brakes

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.