Pit stop strategy
Pit stop strategy is the plan for how many times a driver stops during the race, on which laps, and which tyres they use for each part of it. Every driver has to stop at least once in a dry race because of the two-compound rule, but beyond that the choices are open, and they can win or lose a race.
The basic trade-off
A pit stop costs time. The car has to slow to the pit lane speed limit, stop for a couple of seconds, and accelerate back out. Compared with driving past on the track, a stop typically costs somewhere around 20 to 25 seconds, though it depends heavily on the length of the pit lane. At a few circuits it's well under 20 seconds and at others it's closer to 30.
That cost is called the pit loss. Against it, new tyres are faster than old ones. So the question for every race is simple to ask and hard to answer: does the time gained from fresher tyres outweigh the time lost in the pits?
- When degradation is low and the pit loss is high, a one-stop race is usually quickest.
- When tyres wear quickly, stopping twice or more can be faster overall, even after paying the pit loss again.
Often the two options come out very close on paper. That's when other things decide it: track position, traffic, the weather forecast, and what rivals are doing.
Stints and pit windows
The laps between stops are called stints. A typical one-stop might be medium tyres to begin with, then hards to the finish. A two-stop might use softs, then mediums, then softs again.
Before the race, teams work out a pit window: the range of laps where stopping makes sense. Stop before the window opens and the next set of tyres won't last to the end. Stop after it and you've lost too much time on worn tyres.
How teams plan
Teams spend Friday practice doing long runs on each compound to measure how fast the tyres degrade. They combine that with the pit loss, the expected fuel load and how much time is lost in traffic, and run thousands of simulated races. The result is a set of plans for the race, often a main plan and one or two backups.
On race day, the strategists on the pit wall and at the team's factory update those plans lap by lap. Things that change the picture include:
- tyre wear being higher or lower than expected,
- a safety car, which makes a stop much cheaper,
- rain, or the threat of it, and
- rivals stopping earlier or later than expected.
Track position versus tyre advantage
At some circuits, overtaking is so hard that being in front matters more than having faster tyres. Monaco is the extreme example. Teams there will accept being slower on old tyres if it keeps their driver ahead, because the car behind can't get past anyway.
At tracks where overtaking is easier, it's often worth giving up a position in the pits to have fresher tyres than the cars around you, knowing you can pass them on track. Hungary in 2019 is a good example: Mercedes brought Lewis Hamilton in for a second stop when he was running second to Max Verstappen, and he rejoined about 20 seconds behind. On much newer tyres he closed the gap and passed Verstappen with a few laps to go.
Offset strategies
When two drivers are close on pace, the one behind often tries something different. If the leader is on a one-stop, the chaser might switch to two stops, or stop at a very different time. This is called running an offset or alternate strategy. It gives the driver behind a chance to be on much better tyres at some point in the race, which they can use to catch up.
The driver in front usually tries to cover this by copying whatever the chaser does, typically by pitting on the next lap. That's why stops often come in pairs.
The most common tactical moves around the pit stops are the undercut and the overcut, which have their own page: the undercut and the overcut.
Two cars, one team
A team with two cars near each other has extra options and extra problems. If both need to stop on the same lap, one will have to wait behind the other in the pit box, called double stacking. It costs the second car a few seconds but is sometimes the only sensible choice, especially under a safety car.
Teams will also sometimes use one car to help the other, for example by leaving one driver out to hold up a rival. See team orders for what's allowed.
Why the strategy sometimes looks wrong
From the outside, a pit call can look baffling. Usually the team knows something the viewer doesn't: a tyre showing early signs of damage, a car behind about to pit, a gap in traffic that's about to close, or a forecast showing rain in 10 minutes. That said, teams do get it wrong, and a bad strategy call is one of the most common reasons a fast car finishes lower than it should.