Martin Brundle shot down the idea that McLaren could be using water to cool their tyres, amid alleged Red Bull suspicions over the McLaren MCL39.

With McLaren having made an almighty start to F1 2025, winning five of the six grands prix, Auto Motor und Sport reports emerged over the Miami GP race weekend claiming Red Bull scepticism over the legality of the McLaren MCL39, while McLaren Racing CEO Zak Brown made a cheeky nod to last season’s tyre water allegations.

McLaren MCL39 under the microscope: Tyre theory logic flawed?

AMuS had claimed that Red Bull were using thermal cameras to capture the temperatures of the McLaren MCL39 tyre cooling ducts, with tyre management having emerged as a key strength of the McLaren car.

The main focus was apparently the rears, and Red Bull allegedly noted ‘many blue areas around the brake vents on the McLaren tyres, while all the other cars showed a lot of orange and red’, Red Bull said to have concluded that it is ‘impossible’ to cool the tyres that well with just air alone.

This follows on from late-2024 speculation that McLaren had been injecting a small amount of water into its tyres to aid cooling and thus performance, something which the FIA and tyre supplier Pirelli found no evidence of, and Zak Brown made reference to that when he was seen sipping from a ‘tire water’ bottle on the McLaren pit wall during FP1 in Miami.

Sky F1’s pit-lane reporter Ted Kravitz said he had not spotted any such Red Bull cameras like the reports claimed, but explained it would not be a new trick, revealing that when former Ferrari engineer and strategist Ruth Buscombe began working with the team in 2012, “spying” on rivals with a “heat camera” was her first job.

Speaking on Sky F1’s ‘The F1 Show’ podcast, Kravitz said: “Imola is not looking like it’s going to be a particularly hot race, but let’s see how the hot races benefit McLaren, and their next to no tyre degradation through hot races that’s got all the other teams scratching their heads, how McLaren keep their tyres together so well and cool and everything.

“There was some story that Red Bull were pointing thermal infrared cameras at the McLaren’s tyres. I did have a good scope out, because it’s nothing new.

“Ferrari used to… One of Ruth Buscombe’s first jobs was to stand on the Paddock Club back gantry and spy on other cars with a heat camera. That she’ll tell you, when she joined Ferrari, first job. So that was quite interesting. So there’s nothing new in trying to spy on other people’s hot tyres.

“But, I didn’t see any sort of cameras that Red Bull had set up around the McLaren garage. I’m sure they have very quickly been taken down, but something you can measure.

“But let’s see how they do it, and whether they do it in hot races to come.”

At that point, Brundle stepped in to stress how the historic tyre water allegations simply do not add up.

Brundle made 158 grand prix starts in his Formula 1 career, reaching the podium nine times, and stressed that keeping water out of the tyres was paramount, certainly not putting it in.

“All I know is that I spent all my career hoping that we didn’t have any condensation in the tyres, because you just lose control of the tyre pressure at that point,” he said.

“By putting water in… It makes no sense. It would just turn into steam instantly anyway, pressures would career out of control.

“McLaren have, with their geometry, with their cooling, whatever they’re doing, they’re keeping their tyres intact better than anybody else. But inevitably, in Formula 1, that immediately creates a ‘cheat!’ cry, doesn’t it? Because that’s just how we rock and roll.”

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Bernie Collins – McLaren’s former lead performance engineer and Aston Martin’s ex-strategy chief, explained that the secret to how McLaren look after their tyres will not be found in one specific factor.

“I totally agree with Martin,” she said. “If people understood the lengths that teams go to to get moisture out of the tyres, this story would be… It’s quite funny, actually.

“But, I think there’s hundreds of ways to cool tyres, cool brakes. If you run the brakes at a slightly different temperature, the tyre instantly runs at a slightly different temperature. If you run a slightly different contact patch, the tyre runs at a different temperature.

“There’s hundreds of methods of doing it. It’ll not be straightforward. It’s the whole package.

“And one of the things like we’ve seen this week, McLaren having this advantage in the conditions that we had in Miami, if they have a slightly hotter race and they can run half a second off every lap [sic], I think that’s an extreme number, and if they can run a few tenths off every lap, then you’re managing your tyres a lot better.

“So there’s a whole host of things that go together to get this solution. And teams will try and find out what they can from others through thermal cameras and these things, but there’s so much monitoring now done from Pirelli in terms of before the tyre goes on the car, when it’s on the car, and then when it comes off the car, that it’s very difficult to get around the regulation of what temperature the tyre leaves the garage at and what pressure it goes out at.

“So it’s something to do with their brakes and their cooling ducts around that that are keeping those tyres in a more usable condition for longer.”

McLaren drivers Oscar Piastri and Lando Norris sit one-two in the Drivers’ Championship, Piastri leading the way 16 points up on Norris, while McLaren lead the Constructors’ Championship by 105 points from Mercedes.

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