Pirelli and the FIA have agreed to new procedures for tyre pressure checks in order to avoid the confusion that followed Lewis Hamilton's victory in the Italian Grand Prix.
At Monza, the FIA undertook last minute checks on the four top cars before the race, casting doubt on the legality of Hamilton's car after the race, only for it to emerge that there was a lack of clarity over exactly when Pirelli measured starting pressure.
The Monza stewards called for new procedures to be agreed, and that led to a meeting between Charlie Whiting and Pirelli's Mario Isola in Singapore.
In essence, they have agreed that during practice and qualifying the starting pressure will be that measured when tyres are first fitted to the car.
For the tyres used at the start of the race, the pressure can be measured at any time after the five minute signal on the grid – which means that teams will have to allow for a possible pressure drop after they remove the blankets on the grid.
Crucially, teams will be allowed to adjust the pressures if an anomaly is found.
New directive issued
The FIA has now sent the teams a Technical Directive which notes: “We have been informed by Pirelli that their tyres may only be operated safely if the prescriptions set out in their preview document at each event are strictly followed.”
In explaining the new procedures, the FIA states: “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.”
The FIA adds that in all cases: “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.”
With regard to blanket temperatures the FIA has confirmed that checks will be made on the tread and the sidewall, and that the temperature must be equal to or lower than the maximum set out in the preview.
There is no change to checking camber limits.