What the sporting regulations say:
- Each driver may use no more than one gearbox for six consecutive events.
- Every unscheduled gearbox change will require the driver to drop five places on the grid at that meeting.
- Although gearbox ratios are fixed for the season, teams may change gears or dog rings at any time during an event providing that the FIA technical delegate is satisfied that there is physical damage to the parts in question.
- If a driver fails to finish a race due to reasons beyond his or his team’s control, he may start the next meeting with a different gearbox without incurring a penalty.
What the technical regulations say:
- Cars must have eight forward gear ratios as well as a reverse gear.
- Each team must nominate the eight forward gear ratios at or before the first race of the season. They are then fixed for the year.
- Gear ratios must be made from steel.
- Semi-automatic gearboxes are permitted but automatic gear changes and Constantly Variable Transmission (CVT) systems are not.
- Transmissions may not feature traction control systems, nor devices that help the driver to hold the clutch at a specific point to aid getaway at the start of the race.
- For safety reasons all cars must have a means of disengaging the clutch that is operable from outside the cockpit by marshals. This control is usually situated just ahead of the cockpit opening and is marked on the car’s body by a red letter ‘N’ within a white circle.