For those who don't know: Pirelli introduced a minimum tyre pressure of 19.5 psi on the cars at Monza today, as a safety precaution. As such, any team running at less than 19.5 psi would be making a technical infringement, and a technical infringement warrants a disqualification from the race. It's not exactly clear, but, it seems that someone from the FIA, supervised by Pirelli. used a calibrated gauge to check all 4 tyres on the first 4 cars on the grid (before the warm-up lap started). These were Hamilton, Raikonnen, Vettel, and Rosberg. The rear left of Hamilton's car was 19.2 and the rear left of Rosberg's tyre was 18.4. Rosberg did not finish the race (engine blew up). but Hamilton finished first. Now with it being Monza, one would expect the FIA (Ferrari International Assistance) to come into play, which it did, and Hamilton was told of the infringement only at the end, with a disqualification on the cards. Fortunately, Mercedes were able to show that their procedures, which they had always followed, and which were accepted by Pirelli, showed that the tyres were 19.5 psi when the wheels were in their heated blankets. I also suspect that Mercedes were able to show their telemetry showed that the tyres were always at or above 19.5 psi in the race. On Sky, they showed that the stem and valve are almost identical to the Schrader ones on road car tyres, so it begs the question: why was an FIA official be allowed to check the tyre pressures on the first four cars on the grid , when there are other procedures in place (or m I being too suspicious of the FIA) ?