A tyre controversy has emerged over the Interlagos F1 weekend that adds yet another layer to the battle between Red Bull and McLaren has the title battle hots up.
Red Bull has suggested that some teams – potentially including McLaren – could be gaining an advantage by putting water in their tyres in an attempt to cool them and thus improve race performance.
One way of doing it is pressurising the tyres with air that includes a specific moisture content.
Red Bull is said to have become suspicious after crew members watched tyres from other teams being stripped by Pirelli at the Singapore GP, and apparently saw signs of a fluid.
The practice was once legal, but it was outlawed several years in an FIA technical directive on tyre usage that still applies.
The TD reads “any modification to the inflation gas composition or moisture content aimed at reducing on-circuit pressures is not permitted. This includes increasing as well as reducing inflation gas moisture content, and the addition of any solid, liquid or gas not permitted for this use in the technical regulations.”
Moisture in the tyres would also have the effect of increasing the pressure, although controlling it wouldn’t necessarily be straightforward.
The FIA is looking into the matter but there are no indications of a formal investigation.
Pirelli boss Mario Isola confirmed on Saturday that he is aware of the paddock talk on the subject.
“Obviously, we follow indications from the FIA” he said. “We are happy to support the FIA in any request. If there is anything we can do to check or to give them advice on possible situation.
“We are here to support. I’m not aware of any issue, and I heard all the story, and also tried to understand why it should be done, which now I have an idea. But for the rest it’s all in the hands of the FIA, and we support them as I said.”
He confirmed that the practice was addressed in the TD some years ago.
“There was a discussion also on special gasses,” he said. “Someone said they are changing the gas into the tyre to better control pressure. And then someone started to talk about moisture in the tyre, why we should have more or less.
“We supply the tyres with dry air inside. We have a drier connected to our system, and they get all the tyres with dry air, as in the regulation.
“In the technical directive, it’s written that any modification to this is forbidden, and it’s quite clear. But then you have to have a clear evidence if you have a situation like that. We are waiting for guidance from the FIA.”
Isola noted that adding moisture would not be difficult.
“To do that is very easy,” he said. “You put water inside the tyre, and it’s finished. You have a valve, you put water inside. How the system works is a different story.
“It’s basically a thermal effect, heat transfer between the tyres and the rim that should give more consistency or less degradation to the tyre, even if you have worse control of the pressure.
“Because obviously, if you have vapour or steam inside the tyre, you lose the control of the pressure. You have a pressure that is higher.”
