Formula One cars use semi-automatic sequential gearboxes with seven forward gears and one reverse gear. The driver initiates gear changes using paddles mounted on the back of the steering wheel and electro-hydraulics perform the actual change as well as throttle control. Clutch control is also performed electro-hydraulically except from and to a standstill when the driver must operate the clutch using a lever mounted on the back of the steering wheel. By regulation the cars use rear wheel drive. A modern F1 clutch is a multi-plate carbon design with a diameter of less than four inches (100 mm), weighing less than 2.20 lb (1.00 kg)and handling approximately 900 hp (670 kW).
As of the 2009 race season, all teams are using seamless shift transmissions. Shift times are around 0.05 second for the 2007 season.
As of 2008 race season, all gearboxes must last four consecutive events, although gear ratios can be changed for each race. Changing a gearbox before the allowed time will cause a five places drop on the starting grid.
