The Compounds

Formula 1’s sole tyre supplier, Pirelli, makes a sliding range of dry slick compounds, from the very hard to the very soft. For each event it picks three of them and badges them simply as Hard, Medium and Soft so fans can follow along, marked by the colour of the sidewall.

Behind the three weekend labels sits Pirelli’s full numbered range — from the rock-hard C0/C1 up to the ultra-soft C6. Which three numbered compounds get the Hard/Medium/Soft labels changes from track to track, so a “Hard” at one race can be softer than a “Medium” at another. Pirelli chooses the trio by studying how abrasive the asphalt is, how fast the corners are, and how much energy the layout puts through the rubber.

The choice of trio quietly sets the tone for the race. A soft, aggressive selection means high grip but heavy wear, nudging teams toward two or even three stops; a conservative selection that barely degrades invites a one-stop and turns the race into a track-position chess match. Pirelli deliberately mixes it up across the year to keep strategies varied, and occasionally brings prototype tyres for teams to test in practice as it develops next year’s range.

A driver does not have unlimited rubber to play with. Each one starts the weekend with a fixed allocation of sets and has to hand some back after each practice session, so every lap run in practice spends part of a finite budget. That is why teams sometimes sit in the garage while rivals circulate: they are saving a fresh set for when it counts on Sunday.