Mercedes could lose power unit advantage sooner than expected

At the heart of the matter is the compression ratio of the new power units. Earlier, the FIA presented a proposal in Bahrain to amend the regulations as of August 1, 2026.

Under that plan, the compression ratio would be measured not only under cold conditions (ambient temperature), but also under hot conditions (approximately 130 degrees Celsius).

That proposal now appears to be outdated. The manufacturers seeking to curb Mercedes’ advantage are reportedly not in favour of the proposal in its current form, possibly because they preferred measurements to be conducted only under hot conditions, whereas measuring both cold and hot could also work against them.

A new compromise is therefore on the table, which would bring the implementation date forward from 1 August to 1 June. In addition, a two-step plan is reportedly being discussed: from 1 June 2026, the compression ratio would be measured under both cold and hot conditions, while from 2027 onwards it would be measured exclusively under hot conditions.

However, uncertainty remains over whether the original vote on the first proposal — which may now lack the required majority in its initial form — will still take place, or whether a new vote will be held solely on the compromise now being discussed.

The revised compromise could prove more favourable for Mercedes’ rivals, as the earlier implementation date would limit any potential advantage sooner. Moreover, from 2027 the effect would disappear entirely if measurements are conducted only under hot conditions. In that scenario, the much-discussed “trick” attributed to Mercedes would no longer offer a structural advantage.