why do formula 1 cars need pit stops?

Question

why do formula 1 cars need pit stops?

In: Technology

Answer 1

Pit stops have always been a thing, right back to the very early days, often due to the need to refuel.

As far as modern F1 goes:

During a race if a car uses a harder compound of tyre, it can race for longer, but at an overall lower speed because the hard compound has less grip. A softer compound gives more grip and speed, but won’t last as long. So, running a hard compound for a whole race means the car is slow, but you may not need to stop at all. A soft compound is faster (in some cases, signficantly), but the tyre won’t last for the entire race – forcing a pit stop.

An engineer somewhere thought about this and came to the conclusion that if the car was stopped and the tyres changed, the increased grip (and therefore overall speed) would not only make up for the pit stop but would also have a higher average speed during the course of the race. The theory worked, the way F1 works is if a team find a way to be faster it forces everyone else to do the same thing, so soon the entire field was doing it.

During a race toay, the regulations state that each car must run two different compounds of tyre. The intention of the rule is to try an encourage more racing if the cars pick a different strategy (e.g. which compound they run at which point in the race and how they stagger their pitstops). In reality it doesn’t really, because the teams spend an awful lot of time comparing previous races and endless computer simulations of every combination possible and find the fastest one, so quite often you find many cars on the same compound at the same time and they stop within a few laps of each other.

So, there is a balance. if we have a 60 lap race and the soft tyre only lasts for 15 laps it *might* actually be quicker to run the hard tyre, because the soft tyre doesn’t make up for the long period of time taken in pit stops given we need to make 4. Maybe we could run the hard tyre for say 30 laps and then 2 stints of the soft ? if we push it we could do 45 laps on the hard and 15 on the soft and only stop once.

Trying to make the decision on how we run the race is where the simulations and data from previous races and practice sessions come in.