Pit stops occur when a car returns to the ‘pit lane’, which is runs parallel to the start-finish straight. In each race, every car is obliged to make at least one pit stop. During each pit stop, the driver waits in the vehicle and up to 20 mechanics (known as the ‘pit crew’) make various repairs and modifications to the car.
The Formula 1 regulations stipulate that in each race, every car must use two of the three ‘compounds’ of tyres. They therefore must make at least pit stop to change from one compound to another. These different tyre compounds have different coloured markings on the side of the tyre for spectators to differentiate between them. During a ‘wet race’, these rules are relaxed as drivers are no longer obliged to race using two different type compounds. Instead they race using either the ‘full wet’ tyres, during the rain, or the ‘intermediate’ tyres, during changeable conditions.
Incidents and accidents during the race may require a team to make repairs to a car mid-race. For example, the front wing of the car may have to be replaced if it’s damaged.
In the past, teams were also able to refuel their cars during a pit stop, however 2009 was the last season where this was an option to teams.
One pit crew can only perform a pit stop on one car at a time, so teams must be careful to time the pit stops for their two drivers such that they do not clash. Sometimes teams will have their second car queue behind the first and perform two pit stops back to back. However this is a risky strategy because it puts pressure on the pit crews and introduces room for error. This is called ‘double stacking’ their pit stops.
Another strategy teams will employ when battling one of their rival teams is to bring one of their drivers in to replace their old, worn tyres with new tyres. Their driver, on better tyres than their rivals, aims to then gain on their rivals so that when their rivals make their pit stop, they end up behind them. This is called the ‘undercut’.
Pit crew mechanics can change a tyre in seconds, however making a pit stop is not an easy decision. This is because cars must drive through the pit lane at reduced speeds for safety reasons. This means that a pit stop can take at least 20-30 seconds depending on the track. As a result, when to make a pit stop is an important strategic decision a team must make. The position of rivals, position of their teammate, weather conditions, any damage to the car, tyre wear and other factors are all considerations to take into account when decide when to pit their drivers.