Ferrari’s FIA intervention leaves Mercedes scrambling with last-minute W17 diffuser changes in Austria. FIA clarification reshapes Mercedes' Austrian GP package following Ferrari inquiry.

Mercedes forced into late W17 diffuser revision after Ferrari’s FIA inquiry ahead of Austrian GP

The technical battle between Ferrari and Mercedes intensified even before the first green flag of the Austrian Grand Prix weekend, with the FIA requesting modifications to the Mercedes W17 after Ferrari questioned the legality of part of its rear diffuser design.

While much of the attention at the Red Bull Ring has centred on the Maranello team’s upgraded ADUO power unit and the continued championship fight between Mercedes and the Scuderia, an equally fascinating contest has been unfolding away from the stopwatch. As Formula 1’s leading teams continue to search for every aerodynamic advantage under the 2026 regulations, even seemingly minor components are now coming under increased scrutiny.

Andrea Kimi Antonelli arrives in Austria leading the Drivers’ Championship, although Lewis Hamilton has significantly reduced the gap following Ferrari’s recent improvements. Meanwhile, Charles Leclerc and the Maranello-based team continue working to transform the SF-26 into a consistent challenger capable of matching the Mercedes W17 across every type of circuit.

Ferrari’s latest package in Austria includes the first ADUO engine upgrade, but the Italian squad has also continued monitoring the development direction of its main rival. The rear diffuser used by Mercedes has attracted particular attention over recent races, with Ferrari reportedly seeking clarification from the FIA regarding specific aerodynamic elements introduced by the Brackley-based outfit.

Mercedes had to revise its diffuser before Friday practice

The dispute centred on additional diffuser strakes that Mercedes introduced as part of its Canadian Grand Prix upgrade package. According to reports from the Austrian paddock, Ferrari requested clarification from the FIA regarding whether the extended aerodynamic elements complied with the wording of the technical regulations.

Following the FIA’s assessment, Mercedes was instructed to revise the design before the Austrian Grand Prix weekend. The changes were completed in the limited time available before Friday practice, leaving the reigning constructors’ champions with little opportunity to redesign the component.

Former Aston Martin Head of Race Strategy Bernie Collins explained during Sky Sports F1’s coverage that the most visible alteration involved the final section of the diffuser.

According to Bernie Collins, the small tabs positioned at the very rear of the diffuser had previously extended further backwards to generate additional aerodynamic load. Because of the FIA’s updated interpretation, Mercedes removed the excess material by machining the existing component rather than producing an entirely new specification before the session.

Bernie Collins also noted that Mercedes clearly believed those aerodynamic elements contributed meaningful performance. She pointed out that the extensive aerodynamic rake fitted to the W17 during Friday’s running suggested the team was carefully measuring how much downforce had potentially been lost following the mandatory modification.

FIA clarification affects more than one Formula 1 team

Mercedes was not the only constructor impacted by the FIA’s latest technical clarification. Ahead of FP1, Formula 1’s governing body issued further guidance on how Article C3.2.6 of the 2026 Technical Regulations should define the trailing edge of the rear diffuser.

The clarification forms part of the FIA’s wider effort to prevent teams from exploiting increasingly creative interpretations of the aerodynamic rules to generate additional rear downforce beyond the intended limits of the regulations.

According to reports from the Austrian Grand Prix paddock, Racing Bulls also had to revise aspects of its diffuser design to comply with the updated interpretation. Ferrari, meanwhile, had submitted its own diffuser concept to the FIA for review during the development process, but the current SF-26 specification did not require any modifications before taking to the track at Spielberg.

Although the aerodynamic adjustments appear relatively small on paper, Formula 1 teams regularly find performance gains worth several hundredths of a second in precisely these areas. With Mercedes and Ferrari separated by increasingly fine margins in both qualifying and race pace, even a subtle change to diffuser efficiency could prove significant over the remainder of the Austrian Grand Prix weekend.