Mercedes under investigation for tyre pressures
Mercedes has been informed that both its cars were found to have illegal rear tyre pressures, and are hence under investigation by the stewards. A team representative has been asked to explain.
Document 48 of FIA technical delegate Jo Bauer outlines that 4 cars were tested, and for both Mercedes cars, the left rear tyre pressures were found to be below the minimum required value of 19.5 PSI, a requirement set by Pirelli on Friday after publishing its findings on the tyre failures at Spa-Francorchamps.
The report reads: "On the grid and after the 5-Minutes signal the tyre starting pressure and tread surface temperature of the left hand side rear tyre were checked on car numbers 44, 06, 05 and 07 and were compared with the specifications of the official Formula One tyre supplier. The specification for the minimum starting pressure is 19.5 PSI for the dry weather rear tyres and the maximum tyre blanket temperature is 110 °C for all dry weather tyres."
"The tread surface temperature of the left hand side rear tyre of car numbers 44, 06, 05 and 07 was within the specification of the official Formula One tyre supplier.
The measured minimum tyre starting pressure of the left hand side rear tyre of car numbers 05 and 07 was above the specified minimum tyre starting pressure. The measured minimum tyre starting pressure of the left hand side rear tyre of car number 44 was 0.3 PSI below the specified minimum tyre starting pressure and the measured minimum tyre starting pressure of car number 06 was 1.1 PSI below the specified minimum tyre starting pressure.
"The tyre pressures were checked with the calibrated tyre pressure gauge of the official Formula One tyre supplier on all four cars."
A team representative was subsequently called to the stewards at 15:04. As soon as Mercedes knew it was facing a possibly penalty, Hamilton's race engineer asked the Brit to push and extend his lead over second placed man Vettel, hoping to cover a possible post-race time penalty.
