Track bikes are designed for use on a type of bicycle track known as a velodrome; this velodrome is made of wood flooring and the track itself is sloped upward. The overall structure resembles a large bowl, and as the cyclists pick up speed, they will ride along the upward slope of the track. Track bikes are fixed wheel bicycles, which means a cyclist cannot coast. The pedals will be moving as long as the rear wheel is moving, and the bikes usually do not feature any brakes. A more trendy type of bike modeled after the track bike is the "fixie."
A "fixie," or fixed gear bike, works in a similar fashion as track bikes, but is mostly used on roads by bike messengers and commuters. The popularity of these bikes has exploded because of the neat, simple aesthetic of these bikes and the challenge of riding them. Sometimes a bike designed for commuting will feature a front brake only, though some feature no brakes at all and the cyclist will need to master the technique known as the skid stop. The only way to stop the bicycle is by stopping the pedals, thereby causing the rear wheel to skid.
Track bikes designed for racing are usually exceptionally lightweight and simple, and they are designed for aerodynamic performance. Carbon frames are popular for rigidity and light weight; the bike does not feature any braking systems, and the cyclist is secured to the pedals by using clipless pedals and shoes. The shoes feature a cleat that clicks into the pedals. When the cyclist needs to release from the pedals, he will simply kick his heel outward away from the bicycle.
Cyclists who ride fixies around town will usually use either clipless pedals or toe clips. Toe clips are cages in which the cyclist can slip his feet. They are cinched down around the foot with an adjustable strap and they offer the cyclist more control over the pedal stroke, as well as more power when pedaling. These track bikes are often made with refurbished parts, and vintage bikes are often stripped down to the bare minimum of parts. The aesthetics of these bikes are usually not as sleek and streamlined as track bikes used for racing, though many fixie owners prefer the used, vintage look. Steel frames are most commonly used for fixies, and the handlebars are often very narrow for negotiating tight spaces between cars in traffic.