vehicle most commonly used for transportation is a utility
bicycle. Utility bicycles tend to have a more relaxed geometry,
with priority given to the rider's comfort. Most come with
components that make commuting by bicycle more practical, such as
fenders (also called mudguards in some English speaking regions),
racks (for mounting cargo bags or baskets), chainguards,
kickstands, bells and generator light systems.
The two most
popular types of bicycle in North America, where cycling for
recreation is more common, are mountain bikes and road bicycles.
They tend to have a more aggressive geometry which requires the
rider to bend forward more. To reduce cost and weight, those types
are usually sold without the components that make utility bicycles
The price of a
new bicycle can range from US$50 (on sale) to more than US$10,000,
depending primarily on the quality, type and weight (the most
expensive road bicycles can weigh as little as 6 kg (13 lb)
A bicycle, or
bike, can be defined generally as a pedal-driven human-powered
vehicle with two wheels attached to a frame, one behind the other.
The International Union of Cycling adds the provision that the
seat be more or less above the pedals, thus excluding recumbent
in 19th-century Europe, bicycles now number over one billion
worldwide,providing the principal means of transportation in many
regions, notably China and the Netherlands. They are also a
popular form of recreation, and have been adapted for use in many
other fields of human activity, including children's toys, adult
fitness, military and local police applications, courier services,
and cycle sports.
The basic shape
and configuration of the bicycle's frame, wheels, pedals, saddle,
and handlebars have hardly changed since the first chain-driven
model was developed around 1885, although many important details
have since been improved, especially since the advent of modern
materials and computer-aided design. These have allowed for a
proliferation of specialized designs for individuals who pursue a
particular type of cycling.
The bicycle has
affected history considerably, in both the cultural and industrial
realms. In its early years, bicycle construction drew on
pre-existing technologies; more recently, bicycle technology has,
in turn, contributed ideas in both old and newer areas.