Pirelli responds to latest Red Bull-McLaren technical storm

Pirelli motorsport boss Mario Isola says there is "no evidence" to support allegations some F1 teams have been using water to cool tyres in grands prix. 

Across the Sao Paulo GP weekend, it was claimed that Red Bull had asked the FIA to look into the idea that McLaren, amongst other teams, were using water in the tyres to dissipate heat, thus making their tyres last longer. 

It is the latest technical tit-for-tat between the championship challengers after controversy over McLaren's low-downforce flexi-wing in Azerbaijan that prompted minor modifications, although that wing was only set to be used in Las Vegas for the remainder of the season. 

In the United States, allegations emerged that a team, later self-identified as Red Bull, had a device on the car that could lower front bib of the car in parc ferme conditions - thus changing the ride height. It would be a serious breach of the technical regulations if proven - although there is no evidence Red Bull ever used the device to cheat.

When questioned about the latest technical saga, Isola explained how from the data Pirelli gathers, there was no clear evidence that water-cooled tyres were being used.

"We follow indications from the FIA, we are happy to support the FIA in any request, and if there is anything we can do to check or give advice on a possible situation, we are here to support them," he told media including RacingNews365.

"Before the [technical directive] came years ago, there was a discussion on special gasses as someone said that they were changing the gas in the tyre to better control the pressure - and then someone started to talk about moisture in the tyre and why we should have more or less.

"We supply the tyres with dry air inside, and as in the technical directive, any modification to this is forbidden and it is quite clear - but you would have to have clear evidence for a situation like that, so we should wait for guidance from the FIA. 

"I have tried to understand myself how it works, and I collected this information, but if it works, and if anyone did it or not, it is still a question mark.

"I cannot see anything strange from the data we have, so I don't have any evidence - and obviously it is up to the FIA to decide what to do and tell is where we can [offer] support."

How water-cooled tyres actually work

Isola then went onto describe just how a team would go about placing water inside the tyre, and what the desired effects - and drawbacks - would be of such an action.

"How to do it is very easy, you have a valve, you put water inside, and it is basically a thermal effect of the heat transfer between the tyre and the rim that should give more consistency or less degradation to the tyres - even if you have worse pressure control," he explained.

"If you have vapour steam inside the tyre, you will lose control of the pressure, which is higher. 

"The theory behind it is that part of the water stays liquid, and part of the water evaporates, and because of that, you are able to transfer heat from the tyre to the rim.

"I am not aware of any issue, I heard the story and tried to understand how it would be done, of which I now have an idea, but the rest is in the hands of the FIA, and we support them.