Why Ferrari’s aerodynamic idea was rejected while Mercedes received approval. How Mercedes brought to the track a concept Ferrari was forced to abandon.

The story is particularly fascinating because it offers a revealing glimpse into what modern Formula 1 has become. There is often endless discussion about industrial espionage, spy photographers and stolen technical secrets, but the reality is frequently far more straightforward and, in some cases, even more intriguing.

According to reports emerging from the paddock, Ferrari has been left frustrated after an aerodynamic solution developed by the technical department led by Diego Tondi and Franck Sanchez for the rear section of the SF-26 was rejected by FIA technical officials earlier in the season. What has generated controversy is that a very similar concept later appeared on Mercedes’ W17 and was initially allowed to run.

The situation has quickly become one of the most discussed technical stories in Formula 1, raising questions about interpretation of the regulations, the exchange of knowledge between teams and the increasingly fine line separating legal innovation from prohibited design concepts.

The aerodynamic solution at the centre of the controversy

Among the upgrades introduced by Mercedes at the Canadian Grand Prix in Montreal was an interesting modification to the trailing edge of the rear diffuser. Observers immediately noticed similarities with a concept that Ferrari had reportedly explored during the development of the SF-26 before seeing it rejected by the FIA.

According to information first reported by Autoracer.it, Ferrari, together with several other teams, is believed to have submitted a request for regulatory clarification to the FIA regarding the Mercedes solution. Sources suggest that before the Monaco Grand Prix, FIA technical delegates led by Jo Bauer asked Mercedes to revise the serrated extensions featured on the diffuser. The Federation reportedly imposed stricter limits on the interpretation brought to the track by technical leaders James Allison and Simone Resta.

While the solution was not completely outlawed, the FIA is understood to have requested modifications that narrowed the scope of what Mercedes could legally implement.

Ferrari’s surprise in Maranello

What reportedly surprised Ferrari the most was discovering that the concept visible on the Mercedes closely resembled an idea that had already been evaluated within the Scuderia’s racing department.

The concept had originally been part of a much broader and highly innovative rear-end development programme studied during the creation of the SF-26. That package eventually evolved to include several advanced solutions, including the blown exhaust concept linked to the STM system and the introduction of the now well-known reverse wing configuration. For Ferrari engineers, seeing a similar concept appear on a rival car after their own version had been rejected naturally raised questions. The episode has reportedly generated considerable irritation within Maranello, particularly because the team believed the FIA had already expressed a clear position on the original idea.

However, Formula 1 has often shown that the difference between an illegal concept and a legal one can come down to subtle design details, dimensions or implementation methods.

Could Ferrari revive the concept?

Despite the initial rejection, there is growing speculation that Ferrari may not have completely abandoned the idea.

Several sources believe the solution placed on the shelf earlier in the season could be revisited in the coming races. If Ferrari’s engineers are able to reinterpret the concept within the boundaries clarified by the FIA, the aerodynamic package could potentially return as part of a future development programme.

That possibility makes the story even more interesting because it suggests Ferrari may still see value in the concept despite the regulatory complications encountered during its initial evaluation.

With development becoming increasingly important as the 2026 season progresses, teams are constantly searching for innovative ways to generate additional downforce and aerodynamic efficiency without violating the regulations.

How did Mercedes develop such a similar idea?

The most intriguing question remains how Mercedes arrived at a concept that appears so closely related to one previously studied in Maranello.

To be fair, the use of serrated trailing edges on aerodynamic components is not new at Brackley. Variations of this design philosophy have appeared on Mercedes cars in previous seasons, meaning the team already possessed considerable experience in this specific area of aerodynamic development.

Nevertheless, paddock speculation has inevitably focused on another possibility. Formula 1 experiences a constant movement of engineers between teams, particularly during the winter months. It is therefore not uncommon for technical personnel to bring knowledge, experience and understanding acquired at previous employers to their new organizations.

According to rumours circulating in the paddock, it is possible that among the engineers who changed teams there may have been individuals familiar with both Ferrari’s rejected concept and the FIA’s reasoning behind its decision. Such knowledge could potentially help another team understand which areas required modification in order to transform a rejected idea into a legal solution.

There is no suggestion of wrongdoing, nor any evidence that confidential information was improperly transferred. However, Formula 1 has always operated in a highly competitive environment where technical expertise and accumulated experience often move together with the people who possess them.

A reminder of Formula 1’s technical complexity

Far from the popular image of secret photographs and industrial espionage, many technical innovations emerge through a combination of regulatory interpretation, engineering creativity and the movement of highly skilled personnel throughout the paddock.

Whether Ferrari eventually reintroduces its own version of the concept remains to be seen. What is already clear, however, is that the debate surrounding the serrated diffuser edge has highlighted once again how fiercely teams compete not only on the racetrack but also in the technical offices where Formula 1’s most important battles are often fought.