At Monaco, an F1 driver will make a gear change every 2 seconds on average.
The Gearbox is mounted at the back of the engine and is (usually) made of carbon-fibre. Its job is to transfer the power from the engine to the wheels in the most smooth and efficient manner possible. Modern F1 cars have done away with cables and manual clutches – cars are now fitted with electronic fly-by-wire devices; Gears are selected by paddles on the steering wheel. Electro-hydraulics perform the actual gear change meaning the driver can keep his foot firmly to the floor. Modern F1 clutches are made of carbon-fibre. They are less than 1cm in diameter and weigh less than 1kg.
In a race weekend, mechanics will replace every cog in the gearbox to reduce the chances of failure. The ratios of the gearbox are changed according to the track – how much acceleration and top-speeds the driver will need. Top gear (seventh) is adjusted first to make sure the car is approaching the rev limit at the end of the main straight. It is adjusted to slightly under the rev limit to allow for a revs increase for when the driver is in the slipstream of another car. The lowest gear will then be adjusted to give the best acceleration on the slowest corner of the track. The other gear ratios will then be adjusted to approximately equal intervals between first and seventh gear. This whole process takes about 40 minutes to complete.
During a race, the gearbox can feel temperatures of up to 100 degrees centigrade and it will see thousands of gear changes. It takes about 20 milliseconds for a gear change to happen and this is incredibly tough on the gearbox. This means it is really important to make sure there is enough oil in the gearbox and that it is working well. There will always be a trade-off between the efficiency of the oil (the lubrication) and the protection it gives the gearbox.