Motorcycle speedway, usually referred to as speedway, is a motorcycle sport involving four and sometimes up to six riders competing over four anti-clockwise laps of an oval circuit. Speedway motorcycles use only one gear and have no brakes; racing takes place on a flat oval track usually consisting of dirt, loosely packed shale, or dolomite (mostly used in Australia and New Zealand). Competitors use this surface to slide their machines sideways, powersliding or broadsiding into the bends. On the straight sections of the track the motorcycles reach speeds of up .