Motorcycles used in motocross racing are modified to improve off-road performance and handling. The motorcycle pictured here has a light, powerful engine; large wheels with knobby tires for improved traction; and flat, wide handlebars to maximize the racerís control in bumpy terrain. A racerís gear is equally important. It must protect against injury without trapping body heat or overly restricting movement. Racers wear ventilated helmets, plastic body armor, heavy gloves, flat-soled boots, and knee pads.
In comparison to street motorcycles, off-road motorcycles have narrower, lighter frames, increased ground clearance, and sophisticated suspension systems. Most are powered by single cylinder, two-stroke or four-stroke engines with displacements ranging from 250 to 500 cc. They often have a kick-starter rather than an electric starter to reduce weight. Large diameter tires with a knobby tread pattern provide increased traction, and a large gear on the rear wheel multiplies engine torque for climbing hills. Straight, wide handlebars provide extra leverage. If used strictly for off-road riding, the cycle may not have lights, mirrors, a horn, or a muffler. Most off-road motorcycles have flexible plastic fenders and fuel tanks to minimize damage in the event of a fall. Riders typically wear extra protective gear, including chest, knee, elbow, and shin protectors.