A bicycle, also known as a bike or velocipede, is a human-powered, two-wheeled machine for getting from one place to another. Millions of people worldwide use bikes for recreation, exercise, transportation and sport (called cycling). Bicycles have handlebars for steering, a seat, and two pedals that are connected to the rear wheel by a chain. The rider pushes on the pedals, which turn the wheel and move the bicycle forward. Bicycles were invented in the 1860s and spread quickly around the world. There are many styles of bicycles, ranging from basic models to highly sophisticated racing machines.
The bicycle’s invention had a major effect on modern culture and helped develop the modern industrial world. It is the most efficient means yet devised for converting human energy into mobility. Many of today’s advanced components for the bicycle, such as ball bearings, pneumatic tires, and chain-driven sprockets, were developed to improve efficiency and reduce costs.
Bicycles are available in many sizes, from tiny to big and heavy. Some are designed for children and feature smaller-diameter wheels and child-sized seats, handlebars, and crank arms. Other designs are intended for adult riders and may have features such as adjustable handlebar height, derailleur or internal hub gearing, and hydraulic disc brakes. Adaptive bicycles, which include hand-cranked and recumbent models, help people with nerve, skeletal, or muscle issues that prevent them from riding conventional upright bikes.
Performance bikes are built for fast, long rides on paved roads. They often feature lightweight frames and components, a more comfortable rider position than regular bikes, wider tires for more stability and traction, and a wide range of gearing to handle climbs or descends. Some are equipped with accessory mounts for racks and bags to allow them to carry loads for longer distances.
The bicycle craze of 1868 began with an American newspaper, The Velocipedist, and spawned several small manufacturers. It ended, however, when long-distance bicycle travel was found to be impractical and Calvin Witty’s patent monopoly made further development difficult.
Bikes can be modified to make them more useful for specific uses, such as racing or touring. Specialized tires, racks and carriers, lights, and other accessories can be added. Many cities have programs to encourage the use of bicycles by constructing and maintaining safe routes, providing parking spaces for bicycles, and educating people about safety and the benefits of riding.
A person operating a bicycle on a roadway is a user of that roadway and must obey all laws that govern the movement of vehicles on that road, including all traffic signs and signals. The operator must give audible notice when passing a pedestrian or other bicycle, and must yield the right-of-way to such traffic when it is safe to do so. Bicyclists must also ride as close as practicable to the right edge of the roadway. If a shoulder or other non-paved surface is available, they should ride on that surface rather than on the roadway. In addition, all motorists must be courteous toward bicycles and give them plenty of room to maneuver.