Russell Tops Bahrain Test as Hamilton's Ferrari Hits Trouble

George Russell set the fastest time for Mercedes on the opening day of F1's final pre-season test in Bahrain, while Ferrari's previously flawless running was interrupted by a technical issue that limited Lewis Hamilton's track time. The day also featured a trial of a new start procedure and a significant FIA proposal for a mid-season engine rule change aimed at closing a regulatory loophole.

Why it matters:

Ferrari's first significant reliability setback in testing raises questions about the team's preparedness, just as Mercedes and McLaren showed strong, trouble-free pace. The proposed engine rule change could directly impact Mercedes' competitive advantage and reshape the development race, making the political and technical battles as intense as the on-track action heading into the season opener.

The Details:

• Mercedes and McLaren lead the way: Russell's 1:33.459s narrowly beat McLaren's Oscar Piastri, with both teams completing extensive, reliable running (145 laps for Mercedes, 124 for McLaren).
• Ferrari's mixed day: Charles Leclerc was third-fastest, but Hamilton lost 90 minutes of afternoon running due to a technical issue before returning to complete 44 laps, finishing the day eighth.
• Other team struggles:
  • Red Bull's Isack Hadjar had a water system issue limiting his morning run.
  • Aston Martin continued to face challenges, with Fernando Alonso and Lance Stroll combining for only 54 laps.
  • Newcomers Cadillac again struggled with reliability, managing just 59 laps total.
• Start procedure trial: The FIA trialed an additional five-second pause before the start light sequence to accommodate the new 2026 power units' preparation needs.
• Proposed engine rule change: The FIA has tabled a vote to amend how engine compression ratios are measured, proposing a new test at operating temperature to close a loophole that rivals believe benefits Mercedes.

What's next:

The final day-and-a-half of testing continues, with teams scrambling to gather last-minute data and reliability checks before cars are shipped to Melbourne.

• The proposed engine regulation change requires a super-majority vote from the five manufacturers, the FIA, and F1 itself to be implemented in August.
• All eyes will be on Ferrari to see if Hamilton's issue was a one-off glitch or a symptom of a deeper problem, while Mercedes and McLaren will aim to consolidate their strong testing form.