It is widely believed that Mercedes has exploited a loophole in the F1 2026 engine regulations, potentially opening the door to a season of dominance for George Russell and Kimi Antonelli.

What’s behind the push among rival manufacturers to change the way compression ratios are measured mid-season? And why might the FIA and Formula 1 give in? Hmm…

Slowing down Mercedes would be anti-sport, but might rescue the F1 2026 season

A version of this article originally appeared in PlanetF1.com’s conclusions from Bahrain testing

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How do we know that Mercedes’ compression ratio trick is almost certainly legal? For that matter, how do we know there even is a trick, or a loophole or a grey area?

There has been no evidence, no proof, no admission, just hearsay and finger pointing leading to the common consensus that it’s ‘Mercedes wot dun it’.

Mercedes feels it has done nothing wrong. Just refer back to Toto Wolff’s comments at the team’s season launch earlier this month.

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Asked about the mounting opposition from rival manufacturers, Wolff told PlanetF1.com and other media outlets that “communication with the FIA was very positive all along” during the development of Mercedes’ 2026 engine.

If it’s good enough for the FIA, it should be more than good enough for everyone else too.

It is common practice for teams working on a particularly risky or innovative design to maintain dialogue with the FIA throughout the development process to ensure that it remains on the right side of the regulations.

Mercedes, you’ll recall, previously did it this way while working on its Dual-Axis Steering (DAS) system for the 2020 season, reaping the rewards for 12 months before it was banned for 2021.

For the tide to suddenly turn on the eve of 2026 – it is possible that a change to the way compression ratios are measured will be made in August after 13 races of the new season – leaves a sour taste.

It is fundamentally anti-sport to close off the advantage a team has created for itself just because the rest have missed a trick and have no other option left but to kick up a stink.

Yet this entire episode is also another reflection of the hole F1 has dug for itself with these new rules.

However unfair it would be from a sporting perspective, moving to shut down the avenue Mercedes has (apparently) pursued – estimated by some to be worth around 0.3s per lap – offers a way out for the sport’s authorities.

It represents an easy win. A chance to salvage what could otherwise be a highly unsatisfactory season  (not that, sitting here now, we have any way of knowing that).

If the rule changes for 2026 do indeed turn out to be one great misstep, after all, the last thing the sport needs is one team being too good for the common good.

Nothing would be more damaging than a season with cars too complex for fans and rules they don’t understand anyway… and George Russell wrapping up the title with nine races to go.

Put another way, if F1 really has just gone and neutered itself, neutering Mercedes too suddenly doesn’t seem that big a leap.

The great danger, of course, is what kind of precedent it will set.

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