The effects of Sebastian Vettel’s tyre deflation in the closing laps of the 2015 Belgian GP are still unravelling.
Pirelli have apparently won the day and their argument that when the teams run marginal tyre pressures is a significant contributory factor to deflections and or punctures.
The FIA have backed Pirelli and there are now minimum tyre pressure settings laid out for each race weekend. These differ depending on the nature of the circuit and the ambient conditions.
Mercedes were found to have tyres on both cars below the pressure set by Pirelli, but explained that this was because the tyres had cooled since they were inflated to the correct pressure several minutes earlier.
Tyre pressure and temperature are related mathematically, but essentially Mercedes knew they could start the race with lower tyre pressures by allowing the tyres to cool in the 5 minutes before the formation lap began for the Monza race.
This will no longer be allowed. If Mercedes choose to inflate their tyres at 100 degrees, the will have to keep the tyre blankets switched on and the tyres up to temperature until the formation lap begins.
The FIA have not clearly explained how they will measure the tyre pressure in a statement issued below.
“During all practice sessions, qualifying and race, excluding the set used to start the race, it will be the pressure measured immediately after the set of tyres in question is fitted to the car.
“The race start set will be measured at any time after the five minutes signal.
“When measured, the pressure must be equal to or higher than the minimum set out in the preview. If the pressure is below the minimum requirement teams will be given the opportunity to adjust it.
“Measurements may be taken from any corner of the car.
“Measurements must be made with a gauge calibrated at or by Pirelli, and subsequently sealed by the FIA.
“After the checks have been carried out, and any necessary adjustment made in the presence of a scrutineers, no further adjustments may be made.”
It should be noted, the lack of penalty for having tyres scrutinised and found to be under pressure is a questionable decision from the FIA. Teams can under inflate their tyres and then only if caught will have to put more pressure in at that point.