DoubleCycle.com

A track bicycle is a type of fixed-gear bicycle specially designed for track cycling in a velodrome. Unlike road bicycles, used for road cycling, they lack multiple gears and brakes, having a single fixed gear ratio and no freewheeling mechanism. Tires are narrow, and as the track surface is very smooth there is no need for shock absorption, tires can be inflated to very high pressures well beyond those used in road cycling to minimise the rolling resistance caused by friction. Very lightweight tubular tires can be used as there is almost no risk of punctures. (For grass-track events, the tires would have 'knobs' intended to minimise the potential for skidding.)