After the three days of pre-season testing, Williams and Alpine hung back in Bahrain to help Pirelli with a tyre test focused on the new compounds and constructions for 2026. 

Under this new upcoming regulatory era, the tyres will still be 18 inches in diameter but will be narrower in width by 25 millimetres at the front and 30mm at the rear compared to the current specifications. This is being done with the aim of reducing drag and weight.

Even so, going this step narrower is a move that’s had mixed feedback from drivers who’ve taken part in their testing so far. George Russell said that the tyres were “a bit of a challenge compared to the wider tyres we have today”.

“It was quite a step worse with the new tyres,” he said. “That is naturally the case, because they’re just much more narrow.”

Russell’s verdict is in contrast to that of Charles Leclerc who had been expecting a “big difference” in performance with the smaller specifications, but was “positively surprised” when he actually tried them.

According to Mario Isola, the decision to go narrower or keep the tyres the same for the new generation of cars is one that was left to the teams – who reached their verdict to continue developing these narrower tyres in mid-February.

“We spoke to all the teams about this and said: ‘You have to decide, but we need a final decision’. Either we stay on the 2025 sizes or we continue to develop the 2026 tyres. The teams have decided to continue developing the 2026 tyres,” revealed Isola.

Given this, this recent test was conducted using these 275mm front tyres and 375mm rear tyres and was focused on evaluating different constructions of a range of compounds using mule cars based on Alpine and Williams’ 2023 cars: the A523 and FW45, respectively.

On day 1, Carlos Sainz and Alpine’s reserve driver Ryo Hirokawa were behind the wheel and completed a combined total of 247 laps of the Bahrain International Circuit. The running was focused on assessing a number of different constructions of the same compound, though Pirelli haven’t provided details as to what this specific compound was. This is likely to prevent anyone looking too deeply into the lap times of the day, which were provided: Sainz did a best lap of 1:34.740, while Hirokawa’s was 1:35.336.

For day 2, it was Alex Albon and Paul Aron behind the wheel and their work was the opposite to that completed by their teammates. Pirelli were examining various different compound types from the C1 to C3 with just a single construction of each – allowing them to gather baseline data which they can use to compare the different prototypes. Albon completed 120 laps with a fastest time of 1:35.667, while Aron did 130 laps with the quickest being in 1:35.407. 

Unlike pre-season testing, these two Pirelli test days were much warmer and therefore more representative of the typical conditions in Bahrain, meaning the data gathered can be more easily compared to previous runs around this circuit.

Mario Isola said the test was “very useful” in allowing Pirelli to “gather a significant amount of data to take forward in our programme.”

“In Sakhir we continued with a comparison of different types of construction and compound, the latter at the hardest end of the range, to suit the characteristics of this track,” he said. “Now, our colleagues in R&D will analyse the information carefully and provide useful indications so that we can continue to improve the product for the next generation of cars.”

Pirelli have until September to homologate the final tyre constructions for 2026 and will be conducting more testing between now and then to do so – continuing at Silverstone from May 7th-8th where Mercedes will assess the wet and intermediate tyres.