The Formula 1 world is again in a stir in a controversial discussion about the legality of McLaren’s MCL39, the car that dominates the competition in 2025. Both Toto Wolff, team boss of Mercedes and Christian Horner, are counterpart to Red Bull Racing, have openly expressed their doubts about the technology that McLaren uses to win recent Grands Prix. Despite repeated checks by the FIA, which have not established irregularities, the suspicion of illegal practices continues to engage in the minds. The recent decision of the FIA ​​to approve a controversial part of McLaren’s car has led to a surprise and frustration with both team bosses, who have explicitly mentioned McLaren as suspicious.

McLaren’s advance in 2025 is impressive. Led by CEO Zak Brown and team boss Andrea Stella, the team from Woking has shown an unprecedented speed, with Lando Norris and Oscar Piastri who regularly claim the podium places. Their ability to control tire temperatures, especially at the end of long stints, has stunned rivals such as Red Bull and Mercedes. Especially the rear brakes of the MCL39, which keep the rim and band cooler than with other teams, have attracted attention. Red Bull submitted thermal images to the FIA, which showed cold zones around McLaren’s brake drums, which led to speculation about a possible gray area in the regulations. However, the FIA ​​concluded on 6 May 2025 that McLaren’s design is legal, a statement that Horner and Wolff do not accept without a struggle.

Christian Horner, who is known for his sharp statements, has repeatedly challenged McLaren to openly defend their technology. In an interview withMotorsport WeekOn May 15, 2025, he hinted on the impact of an upcoming change in line with the flexibility of front wings, which is more stricter from the Spain Grand Prix. Horner suggested that McLaren and Mercedes would lose performance as a result, but he remained vague about specific allegations of illegality. “They are brilliant in temperature control, but we do not suggest that there is something illegal,” he said, causing doubts. This ambiguous attitude frustrates McLaren that Red Bull has challenged to submit a formal protest if they actually have evidence.

Toto Wolff, usually an ally of McLaren in their fight against Red Bull, surprised many by joining Horner in his skepticism. On May 5, 2025, Wolff said in Miami that he initially believed in McLaren’s integrity, but recent races made him think. “If someone is so dominant, you will ask questions,” he toldRacingNews365. “But I don’t just want to” cheat “without evidence.” Yet he emphasized that McLaren’s performance “almost too good to be true,” with which he fed the suspicions. Wolff’s statements mark a break with his earlier praise for McLaren’s “Integrity” and suggests growing frustration about their own disadvantage.

The FIA’s decision to approve McLaren’s technology has worsened the tensions. Zak Brown reacted fiercely, with a mocking stunt during the Miami Grand Prix, where he drank from a bottle with the “Tire Water,” a direct sneer to Horner’s complaints about tire management. In the meantime, the FIA ​​remains steadfast: no violation has been established after several inspections. Nikolas Tombazis, FIA director, stated that the case was closed, but the constant speculations show that trust in the regulations are faltering.

For Red Bull and Mercedes, the situation is extra painful because McLaren’s dominance threatens their title opportunities. Max Verstappen, who is struggling with an unstable RB21, and Lewis Hamilton, who has not yet found consistent success at Ferrari, see McLaren as an unstoppable power. The Grand Prix of Monaco, where Norris excelled, strengthened the impression that McLaren has a head start that is difficult to explain without asking technical questions. Yet a formal protest seems unlikely, since Horner admits that the FIA’s unanimous judgment is difficult to dispute.

While the season is progressing, McLaren’s success remains a split mushroom. For fans the controversy offers extra tension, but for Wolff and Horner it is a source of frustration. The FIA ​​faces the challenge of guaranteeing transparency, while McLaren seems determined to defend their lead. Whether the suspicions will ever be confirmed remains uncertain, but for the time being McLaren not only dominates the track, but also in the Paddock conversations.