F1 EXPLAINED: How does Pirelli inflate the tyres?

With the 2025 F1 season slowly approaching its final leg, F1Technical's senior writer Balazs Szabo explains how the sport's sole tyre supplier, Pirelli inflate tyres.

Pirelli has been the sole tyre supplier in Formula One since 2011 following Bridgestone's decision to withdraw from the role at the end of the 2010 season.

The Italian manufacturer previously competed in Formula One from 1950 to 1958, 1981–1986 and 1989–1991. In addition to his role in Formula One as sole tyre supplier, Pirelli also supplies tyres for the FIA Formula 2 Championship, FIA Formula 3 Championship and F1 Academy, that form the feeder series to Formula One.

Before the weekend, Pirelli inflates the tyres with compressed air, using a special machine to remove moisture. Then, in the fitting area where all Pirelli tyres for the event are fitted to and stripped from the wheel rims supplied by the teams, special machines pump them up to 60 psi to check that they are correctly seated on the rims.

Then, the pressure is reduced to 45 psi before the tyres are collected by the teams. They can choose whether to keep the dried compressed air or to replace it with nitrogen, an inert, non-flammable gas that is less permeable than oxygen. The use of any other gas or mixture of gases is forbidden in the regulations.

At each event, Pirelli states a mandatory minimum pressure to be set initially, as well as target running pressures that must be met for safety reasons.

For example, on the opening day at July's Hungarian Grand Prix, the minimum starting pressures were set at 22 psi on the front axle and 20 at the rear. At the end of each session, the regulations allow for the minimum pressure to be adjusted to a new mandatory pressure for the following session.