Did Mercedes’ illegal plank wear boost pace and was it caused by upgrade?

Hamilton and Ferrari driver Charles Leclerc’s exclusions from the US GP classification for failing a post-race plank wear check sent shockwaves through the paddock and brought an old F1 regulation back into the headlines. 

It meant Hamilton lost his podium finish behind race-winner Max Verstappen, leaving a bitter bill for Mercedes to swallow after the team’s strongest performance of a troubled 2023 campaign. 

Mercedes team principal Toto Wolff said his side accepted the FIA’s decision and would “take it on the chin”.

“Set-up choices on a sprint weekend are always a challenge with just one hour of free practice, and even more so at a bumpy circuit like COTA and running a new package,” he said. 

“In the end, all of that doesn’t matter. Others got it right where we got it wrong and there’s no wiggle room in the rules. We need to take it on the chin, do the learning, and come back stronger next weekend.”

Hamilton finished just over two seconds behind Verstappen at the chequered flag after a charging final stint that saw the seven-time world champion running on an offset strategy to his former title rival.

Mercedes’ competitiveness was enhanced by a floor upgrade introduced in Austin, which, for Hamilton in particular, gave him renewed confidence in the team’s inconsistent W14 challenger. 

"The step we were able to take this weekend has given me a little bit more confidence in the car to throw it into the corners," Hamilton said, prior to being disqualified.

"I really enjoyed driving around this track. There are still some of the fundamental issues we are having with the car which won't change until next year. But it was really positive to feel the step we had taken.

"Maybe it was only 0.1secs upgrade but there was at least a 0.1secs of confidence it gave me. It is quite interesting when you see what happens when you do have those; it's like a double knock-on effect.”

According to the BBC, Mercedes team insiders conceded that their costly plank error would have made “some difference to the car’s performance”, though they stressed it would not have led to any “significant advantage”. 

Whether or not their modified floor played a role in influencing their mistake remains to be seen, and Mercedes will now have to wait until next weekend’s Mexico City Grand Prix to get a clearer picture.

But with Ferrari also falling foul of the rules with Leclerc’s car, it is perhaps more likely that limited running due to the sprint format and a subsequent lack of set-up time - coupled with COTA’s bumpy track surface - were to blame for Mercedes’ plank wear woes.  

What rule did Mercedes and Ferrari break?

Hamilton and Leclerc were in breach of Article 3.5.9 e) of the 2023 Formula 1 technical regulations, which reads: “The thickness of the plank assembly measured normal to the lower surface must be 10mm [plus or minus] 0.2mm and must be uniform when new.

“A minimum thickness of 9mm will be accepted due to wear, and conformity to this provision will be checked at the peripheries of the designated holes.”

This breach was discovered following random post-race floor checks, with FIA technical delegate Jo Bauer finding excessive wear on the “skids” on the underside of Hamilton and Leclerc’s cars. 

Checks were also carried out on Verstappen and Lando Norris’ cars, but unlike Hamilton and Leclerc, their cars were found to be fine. 

Has this ever happened before?

Yes, there has been previous precedent for such a breach on a couple of occasions in the past. 

Planks, or skid blocks, were added to the bottom of F1 cars from the 1994 German Grand Prix.

The introduction of a 10mm, rectangular shaped wooden plank came in response to the tragic deaths of Roland Ratzenberger and Ayrton Senna at Imola earlier in the season as the FIA looked at ways to improve safety in the sport. 

Michael Schumacher was the first driver to be disqualified due to a plank wear violation, with his Benetton excluded from the results of the 1994 Belgian Grand Prix. 

Jarno Trulli was also initially disqualified for an excessively worn plank after the 2001 United States Grand Prix, however the Italian was reinstated into fourth place following a successful appeal by the Jordan team. 

Hamilton and Leclerc’s plank wear violations were the first in over 20 years, highlighting just how rare such breaches are.