FIA investigation clears McLaren of wild F1 water trick theories

McLaren have been cleared of using an illegal trick to cool their tyres following an FIA investigation after the F1 Miami Grand Prix.

A dominant start to the 2025 season and the MCL39’s superior tyre management has left McLaren’s F1 rivals scratching their heads and holding suspicions the reigning world champions may be doing something untoward.

After winning five of the opening six races of the campaign to open up a comfortable buffer in both world championships, the brake system on McLaren’s car has come under scrutiny.

Red Bull last year accused McLaren of injecting water in their tyres to prevent them from overheating and after a series of dominant wins this season, the theories have not gone away.

That is despite McLaren strongly denying using such a trick and no evidence being found.

Following the Miami Grand Prix, random post-race checks were carried out on Oscar Piastri’s winning MCL39.

F1’s governing body the FIA released a technical delegate’s report ahead of this weekend’s Emilia Romagna Grand Prix which confirmed Piastri’s car was found to be compliant with the rules.

Crucially, one of the checks related to article 11.5 which states that liquid cooling of brakes is forbidden.

"After the race in Miami car number 81 was randomly chosen among the top ten cars for more extensive physical inspections,” the document read.

"Subject to these physical inspections were the wheel bodywork assemblies. The following checks were carried out on all corners: The compliance of all components with TR Article 3.13. Physical checks for compliance with TR Article 11.5 on all four corners.

"All inspected components were found to be in conformance with the 2025 Formula One Technical Regulations.”

Charles Leclerc’s Ferrari was also spot-checked and found to be legal.

The results of the FIA’s checks should go some way in quieting some of the noise surrounding McLaren’s impressive performance so far in 2025.

McLaren boss pokes fun at suspicious rivals

McLaren Racing CEO Zak Brown aimed a thinly veiled dig at allegations from rival teams by drinking from a water bottle labelled “tire water!” on the pitwall in Miami.

“[The water bottle] was poking fun at a serious issue, which is teams have historically made allegations of other teams. Most recently, one team focuses on that strategy more than others,” he said.

"There's a proper way to protest a team at the end of the race, and you have to make it formal, disclose where it comes from, put some money down.

"I think that process should be extended to all allegations to stop the frivolous allegations which are intended only to be a distraction.

"So if you had to put up some money and put on paper and not backchannel what your allegations are, I think that would be a way to clean up the bogus allegations that happened in this sport, which are not very sporting.

"And if someone does believe there's a technical issue, by all means you're entitled to it. Put it on paper, put your money down.

"It should come against your cost cap if it turns out you're wrong, and I think that will significantly stop the bogus allegations that come from some teams in the sport."