Teams of between two and four men or two women compete on a specially built course consisting of a twisting downhill run in a narrow channel of ice. They aim to complete the course as rapidly as possible by taking the best line on the banked bends and maximizing their speed on the straightaways. Bobsleds are made of steel and composite material. The driver is able to steer his bob by pulling on ropes which are connected to a front axle. The maximum weight for a two-man bob is 858lb for a two-woman bob 814lb and for a four-man bob 1386lb.