Coaster brakes Bicycle brake

single-speed coaster brake



cutaway view of husqvarna novo coaster brake hub

first invented in 1898 willard m. farrow, coaster brake , known pedal brake or foot brake ( torpedo or contra in countries, in italy contropedale ), type of drum brake integrated hub internal freewheel. freewheeling functions other systems, when pedaled, brake engages after fraction of revolution. coaster brake can found in both single-speed , internally geared hubs.

when such hub pedaled forwards, sprocket drives screw forces clutch move along axle, driving hub shell or gear assembly. when pedaling reversed, screw drives clutch in opposite direction, forcing either between 2 brake shoes , pressing them against brake mantle (which steel liner within hub shell), or split collar , expanding against mantle. braking surface steel, , braking element brass or phosphor-bronze, in birmingham-made perry coaster hub. crude coaster brakes exist, on children s bicycles, serrated steel brake cone grips inside of hub shell directly, no separate brake pads or mantle. these offer less progressive action , more lock rear wheel unintentionally.

unlike drum brakes (but shimano roller brake) coaster brake designed run internal parts coated in grease quiet operation , smooth engagement. grey molybdenum disulphide greases work in coaster brake, metal-to-metal friction surfaces.

coaster-brake bicycles equipped single cog , chain wheel , use ⅛ in (3.2 mm) wide chain. however, there have been several models of coaster brake hubs dérailleurs, such sachs 2x3. these use special extra-short dérailleurs can stand forces of being straightened out , not require excessive amount of reverse pedal rotation before brake engages. coaster brakes have been incorporated hub gear designs - example awc , src3 sturmey-archer, , shimano nexus 3-speed. can have 8 gears, nexus inter-8.

coaster brakes have advantage of being protected elements , perform in rain or snow. though coaster brakes go years without needing maintenance, more complicated rim brakes repair if becomes necessary, more sophisticated type expanding brake shoes. coaster brakes not have sufficient heat dissipation use on long descents, characteristic made legendary through events such repack downhill race, riders need repack coaster brakes after grease melted or smoked due heat lengthy downhill runs. coaster brake can applied when cranks reasonably level, limiting how can applied. coaster brakes made rear wheels, have disadvantage common rear brakes of skidding wheel easily. disadvantage may, however, alleviated if bicycle has hand-lever-operated front brake , cyclist uses it. disadvantage coaster brake dependent on chain being intact , engaged. if chain breaks or disengages chainwheel and/or rear sprocket, coaster brake provides no braking power whatsoever. hub brakes except disc brakes, coaster brake requires reaction arm connected frame. may require unbolting when wheel removed or moved in fork ends adjust chain tension.