Inside McLaren’s Las Vegas plank disaster – The real reasons both cars failed scrutineering. The McLaren disqualification at the Las Vegas GP stemmed from excessive plank wear.

McLaren, the origin of the disqualification that reopens the championship: fast race and limited testing

Only a mistake from McLaren could put the championship back into play at a stage when it seemed almost decided—and that is exactly what happened. The excessive wear on the plank under the MCL39’s floor was the result of an overly aggressive ride height choice, compounded by a chain of factors. From missed race pace simulations in free practice to a Grand Prix run at high intensity, there were multiple reasons that led McLaren to commit a costly error with serious championship implications.

A unique weekend

The root cause for McLaren was an incorrect assessment of the ride height necessary to avoid exceeding the one-millimeter wear limit on the plank, the resin strip mounted along the car’s floor. Such issues usually occur when there is little time to perform race pace simulations, which are also essential to quantify plank wear. Consider the disqualifications of Lewis Hamilton and Charles Leclerc in Austin 2023, or Hamilton’s disqualification in China this year—both weekends affected by the Sprint format with only a single free practice session.

At Las Vegas, no Sprint was scheduled, but preparation for the Grand Prix was still challenging. The double red flag at the end of FP2 and the wet conditions during FP3 prevented proper race simulations, leaving only a few short stints in FP1. The circuit is notoriously harsh on plank wear, with numerous long straights where cars spend significant time above 300 km/h, and the high downforce compresses the car against the track. In this scenario, McLaren made a serious misjudgment, also opting for the higher-downforce aerodynamic setup of the two tested during FP1.

A surprisingly fast race

Beyond the free practice data, teams usually rely on information from previous editions to estimate plank wear, but this was limited at Las Vegas. This year, the race pace was roughly two seconds faster than in 2024, accelerating plank wear. Several factors contributed to this, including car development, the more robust 2025 Pirelli tires, and a track that, while still slippery, has improved in grip over the past year. Additionally, the race took place at higher temperatures than previous days, with the track hitting 24°C at the start versus 17°C in FP2. These conditions reduced graining and allowed higher sustained speeds.

Nevertheless, McLaren was the only team to make such an error, possibly recognizing the problem too late. In the final laps, the pit wall instructed Norris to perform lift-and-coast, officially to save fuel. However, the reasoning immediately raised questions, as there had already been over three laps of Virtual Safety Car, and the underlying need was to reduce plank wear. Graphics from Federico Albano illustrate how Lando Norris lifted off at the end of the straight, losing nearly four seconds between lap 48 and lap 41.

The anomaly

What is surprising about the disqualification is that Lando Norris’s McLaren exceeded the wear limit at the rear of the plank, whereas the MCL39 is known to be more aggressive at the front. This explains the dry ice drawer McLaren mounts in hotter races in front of the chassis, used to cool the cockpit, which heats up due to friction from the forward part of the plank against the asphalt. Perhaps this also contributed to the team’s error, focusing attention on the usually more critical area and failing to anticipate a problem emerging where least expected.