Held on paved roads, road racing is the most popular form of bicycle racing, in terms of numbers of competitors and events. Road races are mass start events, where riders start simultaneously and race to set finish point. Road racing demands great endurance, bike handling, skill and tactical know-how.
Tactics are based on the aerodynamic benefit of drafting, whereby a rider can significantly reduce the required pedal effort by closely following in the slipstream of the rider in front. Riding in the main field, or peloton, can save as much as 40% of the energy employed in forward motion when compared to riding alone. Some teams designate a leader, whom the rest of the team is charged with keeping out of the wind and in good position until a critical section of the race. This can be used as a strength or a weakness by competitors; riders can cooperate and draft each other to ride at high speed, or one rider can sit on a competitor's wheel, forcing the other person to do a greater share of the work in maintaining the pace and to potentially tire earlier.
Road racing bikes are all about speed. Ultra lightweight frames made of steel, aluminium or carbon fibre. Bikes have narrow 700c (622mm diameter) wheels, with slick tyres around 23mm wide for low rolling resistance and light weight. They have drop handlebars and multiple gears with up to 22 different gear ratios to cope with varying terrain.