5.5 Pit Stops — Sporting Regulations, Article 28

There is no mandatory pit stop requirement under most race conditions; however, the tyre regulations (Article 24.6.a) require that a driver who starts the race on dry-weather tyres uses at least two different dry-weather tyre specifications during...

Source: Article 24.6, Article 28.13, Article 28.11

Send this to your friend — argument over.