The Formula 1 world has been rocked by the latest developments following an intensive investigation by the FIA into McLaren’s rear brake design, with revelations that have sent shockwaves through the paddock and left McLaren CEO Zak Brown visibly unsettled. The probe, initiated after the Miami Grand Prix in early May 2025, centered on suspicions raised by rival teams, particularly Red Bull, about McLaren’s uncanny ability to manage tyre temperatures, giving them a significant edge in the 2025 season. The findings, while clearing McLaren of any rule breaches, have exposed a series of bold claims and counterclaims, raising questions about the team’s tactics and their implications for the sport.

The investigation began when McLaren’s MCL39, driven by Oscar Piastri and Lando Norris, dominated the Miami Grand Prix, securing a 1-2 finish. Rival teams, struggling to match McLaren’s pace, pointed to the team’s superior tyre management as a potential area of concern. Red Bull, in particular, presented thermal images from a third-party source showing unusual cold spots on McLaren’s rear brake drums, fueling speculation that the team was employing unconventional methods to cool their tyres. Some even suggested that McLaren might be injecting water into their Pirelli tyres, a claim that echoed earlier suspicions raised by Red Bull team principal Christian Horner in 2024. The FIA, determined to maintain fairness, conducted a thorough inspection of McLaren’s braking system, including ducts and drums, after the race.

The results of the investigation, announced on May 7, 2025, confirmed that McLaren’s rear brake design was fully compliant with F1 regulations. The FIA’s technical delegate, Jo Bauer, led a meticulous examination that found no evidence of illegal modifications or prohibited substances. Despite the clearance, the scrutiny has not subsided. Rival teams remain convinced that McLaren’s tyre-cooling advantage stems from a “secret” innovation, possibly involving advanced air conduction or specialized materials in the brake cooling system. Mercedes driver George Russell, speaking after the Miami Grand Prix, hinted at McLaren’s “car design secret,” noting that their tyre temperature management was a puzzle the rest of the grid was desperate to solve.

Zak Brown, typically unflappable, has appeared unusually rattled by the ongoing speculation. In a bold move, he challenged Red Bull to lodge a formal protest, suggesting that teams should pay a hefty fee—around £25,000—for such complaints to deter frivolous accusations. Brown’s comments, made in the heat of the Miami weekend, were accompanied by a cheeky stunt where he brandished a “tire water” bottle, mocking Red Bull’s water-injection theory. However, his bravado masks a deeper concern about the potential fallout from the FIA’s spotlight. With McLaren leading both the Drivers’ and Constructors’ Championships, any hint of controversy could destabilize their campaign, especially as the season approaches critical races like the Emilia Romagna Grand Prix.

The FIA’s decision to clear McLaren has not quelled the suspicions of their rivals. Red Bull, in particular, has doubled down on their efforts to uncover McLaren’s secrets, reportedly deploying thermal imaging cameras during pit stops to monitor the MCL39’s tyre cooling ducts. Auto Motor und Sport reported that Red Bull observed “many blue areas” around McLaren’s brake vents, an anomaly compared to other teams’ cars. While the FIA found no wrongdoing, the persistence of these allegations has created a tense atmosphere in the paddock, with some questioning whether McLaren is exploiting a grey area in the regulations.

For McLaren, the investigation has been both a vindication and a challenge. The team’s dominance, with four wins in the first six races of 2025, is undeniable, but the constant scrutiny threatens to overshadow their achievements. Team principal Andrea Stella has remained defiant, emphasizing that McLaren’s success is the result of hard work and innovation within the rules. “We’re pushing the boundaries, but we’re doing it legally,” Stella said in a post-Miami interview. Meanwhile, drivers Piastri and Norris have stayed focused on the track, with Piastri leading the championship by 32 points over Red Bull’s Max Verstappen.

As the 2025 season progresses, the FIA’s investigation into McLaren’s tactics will likely remain a talking point. The governing body has promised to continue its rigorous checks, with new technical directives on wing flexibility set to take effect at the Spanish Grand Prix. While these changes are unlikely to affect McLaren’s tyre management advantage, they underscore the FIA’s commitment to maintaining a level playing field. For now, McLaren remains the team to beat, but the shadow of suspicion looms large, and Zak Brown’s unease reflects the high stakes of staying ahead in Formula 1’s fiercely competitive world.