Bicycle

A bicycle (also called a pushbike) is a two-wheeled vehicle that moves forward under the power of the rider's muscles. The rider pedals two foot pedals, which transfer force to the rear wheel through a chain and gears.

The bicycle is among the world's most widely used vehicles. It is used for daily transport, light cargo, racing, and exercise. It requires no fuel and produces minimal emissions compared to cars.

Main components

The frame is the central structure that holds other parts together; it is typically made from steel, aluminium, or lightweight modern materials. Other components include two wheels fitted with pneumatic tyres, handlebars for steering, a seat, pedals, a chain, and brakes. Some bicycles have multiple gears that allow the rider to climb hills while exerting less effort.

Balance

A stationary bicycle will not balance, but when moving it becomes stable. The rider maintains balance by subtly turning the handlebars in the direction the bike is leaning, which shifts the centre of mass back. Learning to ride a bicycle typically relies on this principle of correction and usually becomes ingrained after a considerable period of practice.

Types

There are many types: road bikes with thin tyres designed for speed, mountain bikes with broad tyres made for rough terrain, city bikes, cargo bikes, and electric bikes (e-bikes) with a motor powered by electricity that supplements the rider's effort. There are also tricycles used for children and cargo.

History and society

Early forms of the bicycle emerged in nineteenth-century Europe and underwent major development after the invention of the chain drive, equal-sized wheels, and the pneumatic tyre. Many countries today have built dedicated bicycle paths, aiming to reduce urban air pollution and congestion.