Caliper brakes Bicycle brake

1 caliper brakes

1.1 side-pull caliper brakes
1.2 centre-pull caliper brakes
1.3 u-brakes

caliper brakes

the caliper brake class of cable-actuated brake in brake mounts single point above wheel, theoretically allowing arms auto-centre on rim. arms extend around tyre , end in brake shoes press against rim. while designs incorporate dual pivot points — arms pivot on sub-frame — entire assembly still mounts single point.

caliper brakes tend become less effective tyres wider, , deeper, reducing brakes mechanical advantage. caliper brakes found on modern mountain bikes. ubiquitous on road bikes, particularly dual-pivot side-pull caliper brake.

side-pull caliper brakes

single pivot side-pull caliper brake.

single-pivot side-pull caliper brakes consist of 2 curved arms cross @ pivot above wheel , hold brake pads on opposite sides of rim. these arms have extensions on 1 side, 1 attached cable, other cable housing. when brake lever squeezed, arms move , brake pads squeeze rim.

these brakes simple , effective relatively narrow tyres have significant flex , resulting poor performance if arms made long enough fit wide tyres. if not adjusted properly, low-quality varieties tend rotate 1 side during actuation , tend stay there, making difficult evenly space brake shoes away rim. these brakes used on inexpensive bikes; before introduction of dual-pivot caliper brakes used on types of road bikes.

dual-pivot caliper brake.

dual-pivot side-pull caliper brakes used on modern racing bicycles. 1 arm pivots @ centre, side-pull; , other pivots @ side, centre-pull. cable housing attaches of side-pull brake.

the centering of side-pull brakes improved mass-market adoption of dual-pivot side-pulls (an old design re-discovered shimano in 1990s). these brakes offer higher mechanical advantage, , result in better braking. dual-pivot brakes heavier conventional side-pull calipers , cannot accurately track out-of-true rim, or wheel flexes side side in frame during hard climbing. common see professional racers climbing mountains quick-release undone on rear brake, eliminate drag source.

centre-pull caliper brakes

centre-pull caliper brake.

this type of brake has symmetrical arms , therefore centre more effectively. cable housing attaches fixed cable stop attached frame, , inner cable bolts sliding piece (called braking delta , braking triangle , or yoke ) or small pulley, on runs straddle cable connecting 2 brake arms. tension on cable evenly distributed 2 arms, preventing brake taking set 1 side or other.

these brakes reasonably priced, , in past filled price niche between cheaper , more expensive models of side-pull brakes.

u-brakes

u-brake on freestyle bmx bike

u-brakes (also known trademarked term 990-style ) same design centre-pull caliper brake. difference 2 arm pivots attach directly frame or fork while of centre-pull caliper brake attach integral bridge frame mounts frame or fork single bolt. roller cam brakes, caliper design pivots located above rim. u-brakes interchangeable with, , have same maintenance issues as, roller cam brakes.

u-brakes used on mountain bikes through 1990s, particularly under chainstays, rear brake mounting location popular. location benefits higher frame stiffness, important consideration powerful brake since flex in stays increase lever travel , reduce effective braking force. unfortunately prone clogging mud, meant u-brakes fell out of favour on cross-country bikes.

u-brakes current standard on freestyle bmx frames , forks. u-brake s main advantage on cantilever , linear-pull brakes in application sideways protrusion of brake , cable system minimal, , exposed parts smooth. valuable on freestyle bmx bikes protruding parts susceptible damage , may interfere rider s body or clothing.