A sidecar is an one-wheeled vehicle attached to the side of a motorcycle, producing a three-wheeled vehicle (however, these are not called tricycles).

The sidecar consists of a frame (which is rigidly fixed to the motorcycle's frame on one side and is supported by the sidecar's wheel on the other side) and of a body. The body typically provides one passenger seat and a small trunk compartment behind. In some modifications the sidecar's body is used for carrying cargo only (like a truck's platform).

The sidecar's wheel is sometimes also driven (typically using a differential gear), to improve the vehicle's ability to go cross-country.

Before the 1950s, sidecars were quite popular, providing a cheap alternative to passenger cars; they have also been used by the army and police. During WW2, German troops used many BMW and Zundapp sidecar motorcycles.

Nowadays sidecars, for road use, are a mere curiosity. Some of the few remaining producers of sidecar outfits are IMZ-Ural and Izhmash in Russia, Dnepr in the Ukraine and Chang Jiang in China (all based on the same WW2 BMW motorcycle). Sidecars are often seen on Russian and Ukrainian roads.

In Europe most sidecars are of the motocross type. These are purpose-built frames made for very tough conditions on race tracks. The sport also have a few followers in United States, Australia and New Zealand.

There are many small producers of sidecars in many countries.

See also

• Cossack motorcycle
• Sidecar cocktail
• Motocross