Rear tyre pressures on Hamilton and Rosberg's W06 found to be below Pirelli's new minimum requirements on grid; Hamilton's dominant win placed under threat for three hours before Merc given all-clear
Thursday 10 September 2015 10:44, UK
Lewis Hamilton has been confirmed as the victor of the Italian GP after stewards cleared Mercedes of any wrongdoing after the left-rear tyre on the world champion's car was found to be below Pirelli's minimum limits at the start of the race.
After Hamilton claimed a dominant 25-second victory at Monza, the race stewards summoned Mercedes over an alleged tyre pressure infringement on the cars of both Hamilton and team-mate Nico Rosberg on the grid.
"The measured minimum tyre pressure on the left hand side rear tyre of car number 44 [Hamilton] was 0.3 PSI below the specified minimum tyre starting pressure," a statement from the FIA technical delegate read. "And the measured minimum starting pressure of car number 06 [Rosberg] was 1.1 PSI below the specified minimum starting pressure."
However, after a lengthy investigation it was decided that Mercedes had acted appropriately and Hamilton's victory would be allowed to stand.
'The stewards have determined that the pressures in the tyres concerned were at the minimum start pressure recommended by Pirelli when they were fitted to the car,' their verdict read.
"In making this determination regarding the pressures, the stewards noted that the tyre warming blankets had been disconnected from their power source, as is a normal procedure, and the tyres were significantly below the maximum permitted tyre blanket temperature at the time of the FIA's measurement on the grid; and at significantly different temperatures from other cars measured on the grid.'
The announcement marked the final act of a dramatic afternoon at Monza on what had been, until the last laps, a fairly uneventful race day in which Hamilton was the leading figure from start to finish.
Confirmation of the result leaves Hamilton over 50 points clear at the top of the standings and seemingly poised to secure his third World Championship.
Hamilton was not told of the issue during the race but argued afterwards that his victory was legitimate.
"If it's 0.3 PSI it's 0.3 – but it had no effect on the car," the Mercedes driver told Sky Sports. "That small amount on the tyre doesn't do anything.
"It has to be a much bigger amount – 0.5 or 1 PSI – to make a difference. Pirelli will be able to prove that it doesn't make any difference, particularly on one tyre. If it's all the tyres maybe you can argue it.
"It would be very much a shame. But ultimately that's not the reason why we won today. We won because we were the quickest"
Following the tyre blowouts of Spa a fortnight ago, Pirelli had increased their tyre pressure recommendations by one PSI both front and rear to guard against any repeat problems at F1's fastest venue.
Pirelli motorsport director Paul Hembery told Sky F1 before the race that teams had "mainly" been keeping within the new prescribed limits. Ferrari's two cars were also checked on the grid and their rear tyres were found to be above the minimum 19.5 PSI requirement.
Monza stewards' verdict in full
'The stewards have determined that the pressures in the tyres concerned were at the minimum start pressure recommended by Pirelli when they were fitted to the car.
'In making this determination regarding the pressures, the stewards noted that the tyre warming blankets had been disconnected from their power source, as is a normal procedure, and the tyres were significantly below the maximum permitted tyre blanket temperature at the time of the FIA's measurement on the grid; and at significantly different temperatures from other cars measured on the grid.
'Further, the stewards are satisfied that the team followed the currently specified procedure, supervised by the tyre manufacturer for the safe operation of the tyres.
'Therefore, the stewards decide to take no further action. Nevertheless, the stewards recommend that the tyre manufacturer and the FIA hold further meetings to provide clear guidance to the teams on measurement protocols.'
