bicycle racing or cycling, an internationally popular sport conducted on closed courses or the open road. Track racing takes place at a velodrome, usually a banked 1,093.6 ft (.333 km) oval. Olympic medals are awarded in individual and team track events, including the sprint, which features a duel between two finalists. Another track event is the pursuit, in which racers begin at opposite sides of the circuit and attempt to catch each other. The Olympics include road races, but the best-known road events are grueling multiday races, especially the Tour de France (begun in 1903), which covers some 2,500 mi (4,000 km) in more than twenty daily stages. Tour de France cyclists ride for teams that share prize money and employ various strategies to aid each other, but an individual winner emerges from both time trials and races over varied terrain, including downhill mountain rides at speeds above 70 mph (113 kph). In 1996 mountain biking, featuring varied off-road events (cross-country, hill climb, slalom), debuted as an Olympic event. Cyclocross, long popular in Europe and gaining in the United States, involves racing around an obstacle-filled course. In recent years, professional bicycle racing has been marred by revelations of the use of performance-enhancing drugs. Several favorites were barred from the 2006 Tour de France as a result of doping charges, and the winner that year, American Floyd Landis, tested positive for high testosterone levels (and presumed testosterone use). In addition, the long-dominant Lance Armstrong was suspected of doping.

bicycle, light, two-wheeled vehicle driven by pedals. The name velocipede is often given to early forms of the bicycle and to its predecessor, the dandy horse, a two-wheeled vehicle moved by the thrust of the rider's feet upon the ground. Probably the first practical dandy horse was the draisine, originated c.1816 by Baron Karl Drais von Sauerbronn, chief forester of the duchy of Baden, to facilitate his inspection tours. Introduced into England in 1818, it was slowly improved, and c.1839 Kirkpatrick MacMillan, a Scottish blacksmith, developed a machine propelled by foot treadles and incorporating cranks, driving rods, and handlebars. The French inventor Ernest Michaux introduced in 1855 a heavy crank-driven bicycle. This was perfected c.1865 by Pierre Lallement, whose velocipede, known as a "boneshaker," ran on ironclad wooden rims, the front wheel larger than the rear. Major improvements followed rapidly, including a light, hollow steel frame, ball bearings, tangential metal spokes, and solid rubber tires.

By the 1880s the front wheel had attained a diameter up to 64 in. (163 cm). Although the larger the wheel, the greater the potential speed, size was limited by the length of the rider's legs, and speed by their strength. The safer tricycle, a three-wheeled vehicle similar to the bicycle, also enjoyed a vogue in the 1880s, especially among women and short men. The safety bicycle, with wheels of approximately equal diameter and a sprocket-chain drive connecting the pedals with the rear wheels, was first manufactured at Coventry, England, c.1885 by the English machinist James Starley; following the invention of the pneumatic tire in 1888 by the Scot John Dunlop, the safety bicycle superseded the high-wheeled form. Subsequent modifications include the freewheel (a rear wheel that turns freely when the pedals are stopped), the coaster brake, the hand brake, variable drive gear, and adjustable handlebars.

In the 1880s cycling became a fad of major proportions in the United States and Europe. Bicycle clubs were formed; both sexes participated in rides into the country, often on tandem bicycles. The League of American Wheelmen, organized in 1880, was a leader in the agitation for good roads. Although cycling declined in the United States with the introduction of automobiles, it has recently grown in popularity, notably since the introduction in the 1970s of wide-tired, off-road "mountain bikes." In many parts of the world the bicycle remains a more important means of transportation than the automobile. See also bicycle racing; motorcycle.

Use of the bicycle in competitive sport or in recreation. The classic professional races are held mainly in Europe; the first was held in Paris in 1868. There are basically two types of race: road races and track races. The first U.S. cycling competition, a six-day race, was held in 1891. Six-day racing was reintroduced to Europe as a two-man team event in the 20th century, but it has largely died out in the U.S. The first Tour de France, the premier race, was held in 1903. Cycling has been part of the Olympics since the first modern games in 1896. Events include a variety of open-road and circuit races for both men and women.

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Lightweight, two-wheeled, steerable machine that is propelled by the rider. The wheels are mounted in a metal frame, and the front wheel is held in a movable fork. The rider sits on a saddle and steers with handlebars attached to the fork, propelling the bicycle with two pedals attached to cranks that turn a chainwheel. An endless chain transmits power from the chainwheel to a sprocket on the back wheel. A heavy, pedalless form built in 1818 was propelled simply by the rider paddling his feet against the ground. In the early 1840s Scottish blacksmith Kirkpatrick Macmillan (1813–78) built bicycles propelled by pedals, cranks, and drive rods; he is widely credited with having invented the bicycle. Important innovations were introduced by Pierre and Ernest Michaux in France in the early 1860s, and by 1865 their company was manufacturing 400 vélocipèdes a year. A lighter version produced in England in 1870 (nicknamed the “penny-farthing”) featured a large front wheel and small back wheel. By the 1890s the standard bicycle design was established, and, with the smooth ride enabled by the new pneumatic tires, its popularity exploded. The so-called mountain bike became the standard design by the early 1990s. The bicycle is used worldwide as a basic means of transportation.

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