Mercedes hit by setback after engine change forced

Mercedes were forced into an early power unit change on day two of Formula 1 pre-season testing in Bahrain.

The F1 field is at Bahrain International Circuit this week for the first of two three-day test sessions ahead of the 2026 season, giving teams their first real opportunity to push their brand-new machinery on track.

There is significantly more testing available this year than usual, with F1 and the FIA tripling track time in an effort to help teams identify and resolve early reliability or performance issues caused by the sweeping new technical regulations.

At last month's private shakedown in Barcelona, however, all 11 teams seemed to be pretty good when it came to their reliability, with Mercedes in particular impressing with over 500 laps worth of running over their three allocated days.

That led to rumours that they were the favourites heading into the season, but Bahrain testing so far has been a little tricky for them.

During the morning session, the broadcaster told Sky live from the circuit: "I am hearing about a potential engine change at Mercedes and they have their screens up.

"Red Bull and Mercedes are not entirely bulletproof in terms of reliability."

Are Mercedes the favourites for 2026 success?

On top of their immense reliability in Barcelona, Mercedes also topped the timesheets on two of the three days in which they were running.

There has been talk of them being the dominant team in F1 this year throughout the winter, with rumours suggesting that they had found a clever trick within their power unit design that could equate to as much as 0.3 seconds per lap.

The alleged trick regards the geometric compression ratios, with it being reported that Mercedes have found a way for the compression ratio to be at the allowed 16:1 when the engine is stationary, but then increase to the previously allowed 18:1 when moving, something that could allow an extra 15 brake horsepower.

Mercedes, of course, dominated the sport the last time we had a wholesale regulations change in 2014, but suffered greatly during the more minor rule change of 2022.

Time will tell as to whether Mercedes really have found this extra pace or not ahead of 2026, but the Brackley outfit are looking in good shape to be able to mount a title challenge, or at least challenge closer to the likes of McLaren than they were last year.

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