Bicycle Brake

A bicycle brake is a mechanical system designed to reduce the speed of a bicycle or bring it to a complete stop by preventing the wheels from turning. Most systems work by converting the kinetic energy of the rider and bicycle into thermal energy through friction between two surfaces. The principal modern types are rim brakes and disc brakes, while drum brakes and several historically important mechanisms, such as spoon and coaster brakes, are less commonly found on contemporary bicycles. A typical bicycle braking system consists of three main elements: a control for the rider (such as a brake lever or a back-pedal action), a means of transmitting force (cables, hydraulic hoses, rods or the chain), and the brake mechanism itself which presses friction surfaces together.

Early History and the Emergence of Bicycle Brakes

The earliest two-wheeled machines had only rudimentary braking systems. Karl Drais’s 1817 “draisine” included a pivoting brake shoe that pressed against the rear iron tyre to slow the machine. As bicycles evolved into high-wheelers or penny-farthings, braking was achieved either with a spoon brake acting on the front or rear solid rubber tyre, or by back-pedalling against a fixed gear to resist the motion of the wheel.
From about 1870 to 1878 a variety of brake designs were tried, most acting on the rear wheel. However, as the front wheel grew larger and carried more of the rider’s weight, rear-wheel braking became increasingly ineffective. A front brake design introduced by John Kean in 1873 gradually gained acceptance and by around 1880 it had been widely adopted because it offered greater stopping power. Riders often combined braking with particular riding techniques: some relied purely on back-pedalling, some dismounted on steep descents, while others coasted downhill with feet off the pedals and legs over the handlebars, a practice that could be dangerous if the rider’s feet came near the spokes.

The Safety Bicycle and the Decline of Spoon Brakes

The invention of the safety bicycle in the 1870s and 1880s, with two wheels of equal size and initially solid rubber tyres, transformed cycle design. These machines generally carried a front spoon brake but often lacked a dedicated rear brake, relying instead on fixed gearing to enable braking by resisting pedal movement. The wooden rims commonly used at that time were too fragile to allow rim braking, which requires direct friction on the rim surface.
In the late 1890s two related developments changed braking practice: the introduction of pneumatic tyres and rim brakes, together with the freewheel that allowed coasting without turning the pedals. With mass-produced pneumatic tyres from firms such as Dunlop, spoon brakes became problematic because they rapidly wore through the thin rubber casing. This led to calls for alternative systems that acted on more durable components.
On 23 November 1897 Abram W. Duck of Oakland, California, patented the Duck Roller Brake, a system that used rod operation from a handlebar lever to pull twin rubber rollers against the front tyre. In 1898, following the introduction of freewheels, the first internal coaster brakes appeared for the rear hub. These allowed the rider to brake by back-pedalling without contacting the tyre itself, and quickly became popular. In the United States, coaster brakes were the most commonly fitted brake during the first half of the twentieth century and often served as the only braking system on a bicycle.

Spoon and Duck Brakes

The spoon brake (or plunger brake) is among the earliest bicycle braking devices and predates pneumatic tyres. A spoon brake uses a pad, frequently leather or a metal shoe sometimes faced with rubber, which presses onto the top of the front tyre. Operation was usually by rod linkage from a right-hand lever on the handlebar. In some parts of the developing world a foot-operated variant was retrofitted to rod-brake roadsters; a spring-loaded flap behind the fork crown could be depressed by the rider’s foot to bear on the tyre.
Spoon brakes were highly sensitive to road conditions and severely accelerated tyre wear, particularly once pneumatic tyres became standard. Despite being rendered obsolete in principle by the Duck brake, coaster brake and rod-operated rim brakes, spoon brakes persisted in the West as supplementary brakes on adult bicycles into the 1930s and on children’s bicycles into the 1950s, and they continued to be manufactured in some regions for much longer.
The Duck brake or Duck roller brake improved on the spoon principle. It used twin friction rollers, usually made of wood or rubber, mounted on axles with friction washers and angled to match the tyre profile. When pulled against the tyre by a rod linkage, the rollers were forced against their washers, generating braking force. A tension spring kept the rollers clear of the tyre when not in use. The very long handlebar lever could be operated with one or both hands to increase leverage. When combined with a rear coaster brake, this arrangement gave riders of the period much greater stopping power and modulation than either device alone. The system was adopted by prominent cyclists, exported to several countries, and adapted for use on early motorised bicycles.

Rim Brakes: Construction and Operation

Rim brakes derive their name from the fact that braking force is applied to the wheel rim. One or more brake pads, made of leather, rubber, cork or composite materials and often mounted in metal brake shoes, are pressed against the braking surface of the rim, thereby slowing the rotation of the wheel and the bicycle. Rim brakes are usually actuated by hand levers mounted on the handlebars, pulling Bowden cables or, in older systems, rod linkages.
Rim brakes come in several designs—such as side-pull caliper, centre-pull, cantilever and V-brake—but all share the basic principle of clamping the rim. They have several notable advantages. Rim brakes are light, mechanically simple, relatively inexpensive and straightforward to adjust or repair. These characteristics make them particularly attractive for road-racing bicycles, where low weight is paramount, and for commuter bicycles at the low to mid price range, where ease of maintenance and low cost are more important than ultimate performance in severe conditions.
However, rim brakes also present disadvantages. Their performance deteriorates when rims are wet, leading to delayed or reduced braking force. Even slight warping or out-of-true rims can cause uneven braking or persistent rubbing of the pads. Because the rim travels close to the ground, mud, grit and snow tend to be carried up to the braking surfaces, making rim brakes more prone to clogging than disc brakes, whose rotors are higher and more shielded from debris.

Maintenance, Wear and Heat Management in Rim Brakes

Rim brake systems require regular inspection and maintenance. Brake pads gradually wear away during use and must be replaced periodically. As pads wear, their alignment relative to the rim can shift, especially since most mechanisms do not move strictly horizontally. Poorly centred or misaligned pads may wear unevenly, diminish braking efficiency or begin to contact the tyre or drop below the braking track.
Over time the rim itself can also become worn. The abrasive contact of pad on rim, especially in wet or gritty conditions, can thin the metal of the braking surface. If the rim wall becomes too thin, structural failure is possible, which may occur suddenly with serious consequences. For this reason rims on bicycles that see heavy braking—such as touring or heavily laden commuter machines—should be inspected regularly for signs of wear.
Braking generates heat at the friction surfaces. In normal riding this heat is quickly dissipated to the air, but on long descents, particularly with a loaded bicycle, heat may build up faster than it can escape. Excessive heating risks damage to the rim, premature pad wear and, in extreme cases, failure of the tyre due to softening of the bead or blow-outs. To mitigate such problems some rims are manufactured with a ceramic coating, which can reduce wear and improve braking in both wet and dry conditions. Ceramic surfaces also act as thermal insulators, slightly reducing heat transfer to the interior of the rim.

Brake Pads and Evolving Technologies

Brake pads are a critical component in rim braking systems. Materials range from simple rubber compounds to carefully engineered mixtures designed to optimise friction, noise, rim wear and performance in particular conditions. Different pad formulations are often recommended for aluminium, steel or ceramic-coated rims. As the demand for reliable braking has grown, especially in sport and mountain cycling, rim brake technology has been complemented and, in some sectors, superseded by disc brakes, which isolate the braking surface from the rim and are less affected by wet conditions or wheel trueness.