Cycling consists of different disciplines with a racing bike for each. In general, racing bikes will be as light as possible, yet still strong and able to hold up to the terrain, the weight of the rider and gear, and any crashes or other demands riders place on the bikes. Frames can be made from aluminum, steel, carbon fiber and titanium.
The road discipline includes road races, triathlons, criteriums, time trails and stage races. Most of these events use variations on the same type of bicycle, a road bike. The geometry is aggressive and places the rider in an enhanced aerodynamic position, especially when riders are in the drops of drop bars. Tires are thin and narrow, and inflated to high pressure, allowing lower rolling resistance. Each component of race road bike is selected for durability and, above all, light weight, helping to reduce the overall drag of the bike.
Specifically designed for time trials, but also used in triathlons, time trial bikes place riders in an extreme aerodynamic position, partly via frame geometry and partly via aerobars that stretch the rider out in front of the handlebars and on the front edge of the saddle. The tubes of a time trial bike are often configured flatter than those of a road bike to cut through the air. These bikes may also have a rear disc wheel, a solid wheel designed for maximum airflow and to reduce wind resistance. The lack of spokes can improve air flow. With a crosswind though, the disc catches wind, decreasing performance.
For cyclocross races, a cross between a road bike and mountain bike is used. This bike, a cyclocross bike, has geometry similar to a road bike. The bottom surface of the top tube is flat so the bike can be easily hoisted and carried on the racer's shoulder when jumping over obstacles. Cross bikes typically have cantilever brakes, located higher on the frame to allow for mud clearance. There can be two sets of brake levers, on the flat top part of the handlebars and above the drops. A cyclocross bike handles well on tight courses, much like a mountain bike. In addition, the wheels are knobby, like a mountain bike's, yet thinner. The tires for cyclocross are typically inflated to pressures between a road and mountain bike's pressure, though some tubeless tires allow lower pressures for more surface contact.
Races performed on a track require a fixed-gear bike that is lightweight, aerodynamic and very stiff. A track bike looks similar to a road bike but does not have brakes and has only one gear. The pedals do not spin freely and are, instead, "fixed," in that they turn whenever the rear wheel spins. The wheels on a track bike are stiffer than most wheels. This feature transfers more power during sprinting. Tires are thin and narrow and inflated to high pressures for reduced rolling resistance.