Christian Horner has responded to Zak Brown’s use of a ‘tire water’ bottle during the Miami Grand Prix weekend.

McLaren’s ability to keep its tyres alive and its temperatures lower than the competition saw suspicions raised towards the end of last season that the Woking-based squad has been utilising water-cooling tricks with its Pirelli tyres – suspicions that have not turned up any evidence of such a practice.

Zak Brown uses ‘tire water’ bottle during Miami GP weekend

On Friday in Miami, during the one and only practice session, McLaren CEO Zak Brown pointedly used a water bottle that was emblazoned with ‘tire water’ stickers in what looked like a dig back at Red Bull following its suspicions.

In Brazil towards the end of last season, Germany’s Auto Motor und Sport reported that Red Bull suspected several teams – including McLaren – of injecting water into the Pirelli tyres to improve cooling, with the amount of water injected via the valves making for appreciable changes in tyre temperatures.

Pirelli, which monitors and tracks the use of every tyre throughout a weekend, has reported that it has not noticed any abnormal behaviour.

“I cannot see anything strange from the data we have,” Mario Isola, Pirelli’s head of F1 and car racing, said after Brazil. “I don’t have any evidence.”

Isola did state that it would be “very easy” to inject water into the tyres, but that doing so would necessarily come with tradeoffs in terms of tyre pressure.

While Isola would not entirely rule out the possibility that a team was utilising water inside its tyres, he reiterated that “I am not aware of any issue.”

With McLaren’s biggest advantage identified by several rival teams as being down to its ability to keep tyre temperatures in check, with no firm answers yet as to how its doing so, Brown’s use of the ‘tire water’ bottle could be interpreted as some tongue-in-cheek goading of its rivals.

On Friday, Horner had quipped that he could send Brown a can of Red Bull if he “needed energising”, but addressed the topic more seriously when he spoke after the Miami Grand Prix – a race in which McLaren’s advantage was evident as Oscar Piastri and Lando Norris claimed a dominant 1-2 more than 30 seconds clear of the rest of the field.

“In Formula 1, there are always going to be questions that are raised. They did exactly the same about the front suspension in our car last year,” Horner told media, including PlanetF1.com, after the race.

“So it’s inevitable when you’re running at the front as we have for the last few years, you always come under more scrutiny. That’s part and parcel of Formula 1.

“In many respects, for the FIA, the teams, all of the teams, do the vast majority of the work, because their resource is far greater, and there’s always a competitor analysis going on across all of the teams. That’s just part of Formula 1.”

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While the rules for F1 2026 see the technical regulations torn up and revolutionised for next season, McLaren’s apparent understanding of the tyres and how to keep temperatures down is a skillset which should have considerable transfer over to next season and, as a consequence, Horner acknowledged that it’s “important to understand” where the advantage is being gleaned.

“Obviously, McLaren is the standout car,” he said.

“They had the kind of advantage that we saw a couple of years ago, and they’re obviously doing a very good job in managing temperatures and, particularly, I think if you look at the end of the medium tyre stint, that was probably where they were the most competitive.

“So that’s what we need to focus on. I think we had brake issues that have compounded the problem in the race, but that’s what we need to understand.”

While Max Verstappen is keeping himself in contention through sheer force of will thanks to some stellar qualifying performances in a Red Bull that appears capable of matching McLaren over a single flying lap, Horner said the advantage McLaren has got will be far more evident over a race distance – particularly at circuits like Miami with high temperatures and degradation.

“I think the advantage is bigger in the race, isn’t it, because everything gets super hot in the race and runs at a much bigger temperature. So the advantage will always be bigger in the race than it is in quali,” he explained.

“Theoretically, if they had put their theoreticals together in quali, they should have been ahead of us.

“I think Max did a did a outstanding job, and was able to get every ounce of performance and they, arguably, underperformed yesterday [Saturday].

“But we knew going into this race, it was going to be very, very hard to beat them. I was actually surprised that Max was able to hold them back for circa 14 laps, I thought it was a very brave display.

“Arguably, that maybe hurt our own race because you’re fighting hard, your tyres are getting hot, but you’re leading the Grand Prix, you’ve got to go for it. I thought he did an outstanding job to keep Oscar behind as long as he did, and then Lando.”

With Verstappen’s race pace hurt by a brake issue affecting his RB21, Horner downplayed the problem as being linked to the Red Bull’s tyre temperatures thus transferring into the braking system.

“No, I think it’s some other issues that we’re dealing with,” he said, “and I think they have been understood.”

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