First of all, we need to have a huge differential between the tyres.
Every race weekend, the teams can only choose one tyre compound, which must be chosen before the weekend itself. There are three compounds each.
On an average circuit like Catalunya, Options would do be 1 sec quicker than Mediums and 2 sec quicker than Primes, yet would require to do 3-4 stops. Mediums would be 1 sec slower than Options and 1 sec quicker than Primes, and would require maybe 1-2 stops. Primes would be 2 seconds slower than Options and 1 second than Mediums, yet can last an entire race distance. Pits stops during a race are not required, and are completely a team decision.
Teams can only use three tyres throughout the entire weekend – The slick compound they have chosen, and the intermediates and extreme wets in rainy conditions.
For an entire weekend the teams will have a total of 3 intermediates and 3 extreme wet tyres. This holds true for all practice, qualifying, and the race. A total of 6 wet tyres would be difficult to last for an entire wet weekend.
The teams will have a total of 6 slick tyres they can use throughout practice of whichever compound they chose for that weekend. They will have 3 sets available in qualifying and for the race, they will have another 3 sets available. Qualifying tyres are different from racing tyres to motivate the teams to go out in Q3.