Williams: FIA measurement was wrong

Massa was excluded from eighth place in the Brazilian Grand Prix after the FIA discovered that the right rear tyre on his Williams was 27 degrees over the limit allowed.

Williams performance chief Rob Smedley said the outfit is baffled as to why the FIA's infra-red gun reading showed the tyre to be at 137 degrees, because its own data suggested the tyre was at 107.

"We have two independent sensors, the first one is the PT1000 which sits inside the tyre blanket and tells us what the surface temperature is, and that one was always in compliance with the regulations," explained Smedley, who confirmed the team would be appealing.

"In fact, the last time we could read it, when they took the set off to the grid, it was about 104 degrees.

"The next independent measure we have is from the car data (see photo). It shows the right rear tyre temperature on Massa's car was 107 degrees.

"So we have two independent sensors, they both say we are in compliance with regulations and we have data to back it up.

"In addition, we have had independent correlation from our blanket temperatures sensors and car temperature sensors to the FIA guns, which Pirelli did for us after all the fuss with Mercedes in Italy.

"And in addition to that, we have also bought exactly the same [IR] sensor that the FIA uses and we do random checks throughout the weekend to ensure it doesn't happen.

"For us it is critical that we understand where this problem came from, but we have three independent measures and none of them give anything like the FIA measurement on the grid."

When asked why, if the team's own data showed the tyre to be within the limits, the FIA reading was so far out, he said: "No idea. That is why we have served notice of appeal.

"There was no explanation whatsoever. They explained to us that this is reference measurement because it is the FIA measurement and so this is the one that counts. The other three that we have are of less consequence."

Pressure clue

Smedley also made clear that there was no unusual rise in pressure inside of the tyre, which would have happened if the tyre had been 27 degrees higher than they thought it was.

"If it was 27 degrees higher, we would see that," he said. "You are probably talking about 2.4-3 psi higher, but the bleed the engineer did on the grid was entirely normal.

"What the engineers would have seen [with a hotter tyre] would be that we were bleeding out an awful lot more pressure than we had been for the rest of the weekend.

"That would have been an anomalous amount of pressure, 3 psi more than he is normally bleeding out, to get down to the Pirelli minimum. That would have been flagged at some point and nothing has."