Track cycling is a bicycle racing sport usually held on specially built banked tracks or velodromes (but many events are held at older velodromes where the track banking is relatively shallow) using track bicycles.
Track cycling has been around since at least 1870. When cycling was in its infancy, wooden indoor tracks were laid which resemble those of modern velodromes, consisting of two straights and slightly banked turns.
One appeal of indoor track racing was that spectators could be easily controlled, and hence an entrance fee could be charged, making track racing a lucrative sport. Early track races attracted crowds of up to 2000 people. Indoor tracks also enabled year-round cycling for the first time. The main early centers for track racing in Britain were Birmingham, Sheffield, Liverpool, Manchester and London.
The most noticeable changes in over a century of track cycling have concerned the bikes themselves, engineered to be lighter and more aerodynamic to enable ever-faster times.
With the exception of the 1912 Olympics, track cycling has been featured in every modern Olympic Games. Women's track cycling was first included in the modern Olympics in 1988.
Aerodynamic drag is a significant factor in both road and track racing. Frames are often constructed of moulded carbon fiber, for a lightweight design, although more traditionally frames are constructed from steel, aluminium, or other metal alloys. More recently, track (and road) bikes have employed airfoil designs on the tubes of the frame to reduce aerodynamic drag.
On a dedicated track bicycle there are few components, with no need for brakes or derailleurs (and therefore shifters). In fact the only moving part on a bicycle is the drivetrain, which includes the cranks, pedals, the single chainring, one cog fixed to the hub without a freewheel mechanism and the chain itself. Because of this the need for aerodynamic components is minimised, and the aerodynamic to weight ratio makes aerodynamic componentry, at present, an idea with more cons than pros. Even in road cycling today, components (excepting brakes and sometimes shifters) are not usually made aerodynamic, even in time trial and 'aero' road bikes.