Each type of cycling requires a specific type of bicycle. Road racing bikes have lightweight frames usually built of steel, aluminum, titanium, or carbon fiber. They are equipped with downward curving handlebars, thin high-pressure tires, narrow saddles, brakes, and a front and rear derailleur that shifts the chain through as many as 16 different gear combinations. The bikes' overall lightness (8 to 10 kg/18 to 23 lbs) and short wheelbase encourage speed and quick handling.
Bicycles come in many shapes and forms. The road bicycle seen here can be used for racing, touring, and recreational riding. Most road bicycles have a lightweight frame, narrow rims and tires, and rounded handlebars so that the rider can lean forward in an aerodynamic position.
Track bikes are similar in appearance and construction to road racing bicycles, except that they lack brakes, have no variable gear mechanism, and weigh about 7 to 9 kg (about 15 to 20 lbs). Mountain bikes are built to withstand the rigorous conditions of off-road riding. Although their frames are commonly constructed of the same materials as other racing bikes, they have sturdier tubing. Mountain bikes are equipped with straight handlebars; wide, low-pressure, knobby tires; powerful brakes; and bar-mounted shift levers controlling up to 24 gears. Many mountain bikes also have some type of front or rear suspension (sometimes both) to cushion the rider against trail shock.
BMX bikes have small wheels and frames to encourage maneuverability and speed. They also have knobby tires for extra traction, and high-rise seatposts and handlebars. They are typically single-speed, and they can employ hand (also called caliper) brakes or rear coaster brakes.
Bicycle racers use other equipment as well. Helmets are essential for safe competition and are required in many races. Racers also use padded gloves and shorts, stiff-soled shoes, and eye protection. BMX racers and mountain bike downhill racers wear the most protective gear, including goggles, face guards, chest protectors, and arm and leg pads.