F1 uncovered: Why Norris and Piastri suffered Las Vegas GP DSQ

The humble plank, a once actual piece of wood strapped to the bottom of a Formula One car, has helped the FIA to govern the ride height limit of the car since 1994.

Almost completely overlooked for the last few decades, this generation of car has proved to be much more problematic in terms of compliance, with numerous teams and drivers falling foul of the legality limit, as McLaren and their drivers became the latest of those to be disqualified after a race for excessive wear.

Why planks play a vital role in Formula 1

The plank was introduced in an effort to slow down the cars after the tragic events of Imola in 1994, where Roland Ratzenberger and Ayrton Senna lost their lives. The idea was that teams would have to raise their cars, having taken to running them as low as possible in order to improve the performance of the floor and diffuser, at the expense of safety.

The plank therefore not only acts as a direct safety measure, it also offers a means to measure how much the car has come into contact with the track’s surface throughout the course of a session, with a minimum thickness of 9mm required in order that the car be deemed legal.

The plank, which is now made of permaglass, a glass reinforced composite, rather than Jabroc as it was in the past and still is in other series, must be 10mm (+/- 0.2mm) and therefore offers just 1mm of tolerance when measurements are taken at the end of a session.

To measure this wear there are four holes drilled into the plank at specific locations, for which the teams can place titanium skids around in order to help defend against excessive damage to the plank.

More from the Las Vegas Grand Prix

👉 Las Vegas GP: Viva Max Verstappen as Lando Norris pays for Lap 1 mistake – and McLaren blunder

👉 Updated F1 points standings after Las Vegas Grand Prix

In the time that’s passed since 1994 there’s only been two instances of drivers being disqualified for excessive plank wear, up until 2023, with Michael Schumacher and Olivier Panis’ cars being deemed illegal following the Belgian and Estoril Grand Prix respectively.

In 2023, both Lewis Hamilton and Charles Leclerc were found to have excessive wear at the United States Grand Prix, whilst the Brit befell the same fate at the Chinese Grand Prix this season.

Meanwhile, Nico Hulkenberg has also been disqualified this season, when the plank on his Sauber was deemed to be excessively worn in Bahrain.

The latest disqualifications for the McLaren duo in Las Vegas obviously have some serious ramifications for the Drivers’ Championship and proves how difficult it is to find the right performance balance with this generation of car, especially during a race weekend with changeable conditions.

The rear skids on Lando Norris’ car were found to be 8.88mm on the right-hand side front and 8.93mm on the right-hand side rear. Meanwhile, the rear skids on Oscar Piastri’s car were measured and found to be 8.96mm on the left-hand side front, 8.74mm on the right-hand side front and 8.90mm on the right-hand side rear.

In order to ensure compliance, the FIA used a Mitutoyo Micrometre to measure this, which is accurate to within 0.001mm.

It’s also understood that teams, having seen a need to run their cars as low as possible for performance gains, have also taken to installing temperature sensors on the skids, in order to monitor the heat that’s being generated.

This would allow them to calculate any wear that’s occurring and offer them the opportunity to instruct their drivers to lift and coast in order that the plank/skids aren’t forced into the track as much at high speeds.

Commenting after the race, Andrea Stella noted: “Both cars experienced unexpected, high levels of porpoising not seen in the practice sessions, which led to excessive contact with the ground.

“We are investigating the reasons for this behaviour of the car, including the effect of accidental damage sustained by both cars, which we found after the race, and that led to an increase of movement of the floor.”

Read next: Lewis Hamilton makes damning Ferrari claim in ‘worst season ever’