The headset is the set of components on a bicycle that provides a rotatable interface between the bicycle fork and the head tube of a bicycle frame. The tube through which the steerer of the fork passes is called the head tube. A typical headset consists of two cups that are pressed into the top and bottom of the headtube. Inside the two cups are bearings which provide a low friction contact between the bearing cup and the steerer.
Parts of a threadless headset before installation
Threaded headset
A bicycle, also called a pedal cycle, bike, push-bike or cycle, is a human-powered or motor-assisted, pedal-driven, single-track vehicle, with two wheels attached to a frame, one behind the other. A bicycle rider is called a cyclist, or bicyclist.
The most popular bicycle model—and most popular vehicle of any kind in the world—is the Chinese Flying Pigeon, with about 500 million produced.
Women on bicycles on unpaved road, US, late 19th century
A penny-farthing or ordinary bicycle photographed in the Škoda Auto museum in the Czech Republic
The Svea Velocipede by Fredrik Ljungström and Birger Ljungström, exhibited at the Swedish National Museum of Science and Technology