Mercedes and Williams wrap up opening day of crucial 2027 Pirelli tyre test

George Russell and Carlos Sainz opened a two-day Pirelli tyre test at Silverstone as the Italian supplier races to finalize its 2027 dry-weather tyre structure. Track temperatures hit 46 degrees Celsius for the opening day, which began with morning screening runs before shifting to longer-run evaluations in the afternoon.

Why it matters:

Pirelli faces a hard September 1 deadline to freeze its 2027 tyre construction under F1 regulations. With manufacturing lead times compressing the development window, this Silverstone session represents one of the final opportunities to validate new structures before the specification is locked in for next season.

The details:

• Russell put in a busy shift for Mercedes, racking up 113 laps and covering 665 kilometres. His best time of 1:30.695 was quicker than the fastest lap set during Sunday's British Grand Prix.
• Sainz managed 61 laps for Williams but was sidelined by a technical issue that curtailed his running. His fastest effort stood at 1:33.567.
• Blind running: Drivers and teams do not know exactly what Pirelli is evaluating. The supplier dictates run plans and fuel loads, and teams are barred from running any car upgrades.
• Wednesday drivers: Mercedes junior Kimi Antonelli and Williams' Alex Albon will take over for the second and final day.

What's next:

With the September freeze looming, Pirelli will analyze data from both test days to settle on the definitive 2027 tyre structure. Williams will be especially eager for a cleaner second day after Sainz's lost mileage, ensuring the team contributes enough feedback to inform the final design.