Carlos Sainz was behind the wheel of a modified 2023 Williams in Bahrain on Sunday, as he completed a tyre test on behalf of Pirelli.

Alpine reserve driver Ryo Hirakawa, fresh from taking part in the opening round of the World Endurance Championship in Qatar, was also involved on the first day of running, as Formula 1’s tyre supplier stay in Sakhir to run their provisional F1 2026 tyres.

Carlos Sainz involved in F1 2026 tyre test in two-year-old Williams

While the running will not have been representative for the coming season, with Sainz having said in Bahrain recently that a day and a half with a new car is “ridiculously little” to get ready for a new campaign, he has at least had more seat time in another day of running on behalf of Pirelli.

Driving the 2023 Williams FW45, Pirelli stated Sainz and Hirakawa both cars were “specially modified” in order to “accommodate the new specification of tyre” they were testing.

Formula 1’s tyre supplier is looking at reducing the diameter of the 18-inch tyres in use from 2026, alongside making them 25mm narrower on the front tyres and 30mm narrower at the rear, while trying to achieve a ‘minimal’ loss in grip.

Sainz clocked another 116 laps of the Bahrain International Circuit, with a best lap of 1:34.740, while Hirakawa managed 131 laps for Alpine with a best time of 1:35.336, with the running focussing specifically on “evaluating various different constructions, but with the same compound” as Pirelli assesses its options for the 2026 season.

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Pirelli will continue testing at the circuit on Monday with modified 2023 machinery, with Alpine fielding another of their reserve drivers in Paul Aron, while Williams will give Alex Albon another day behind the wheel before the new season starts.

Having taken part in 2026 tyre testing already, and with a change in how the tyres measure up from next season, George Russell voiced a concern about the new construction, telling media including PlanetF1.com: “That was a bit of a challenge compared to the wider tyres we have today.

“It was quite a step worse with the new tyres. That is naturally the case, because they’re just much more narrow. So hopefully they will be improved over the upcoming months.”

Mercedes team principal Toto Wolff urged for teamwork between the teams and Pirelli when it comes to the new tyres, too, so they have the best feedback they can get moving forwards.

“I think the most important is that between Pirelli and the teams we we collaborate, and that’s why we’re doing the mule car testing,” Wolff said.

“That the data we collect, the feedback that we get from the drivers, go straight into Pirelli and into the regulations, and we come up with the best solutions. But it’s very easy, those tyres are the same for all of us, so we need to just cope with it, and Pirelli will be keen.

“We need to cope with these regulations and make sure that, for the sake of Pirelli, the sport and the teams, we have the best tyre.”

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