Italian motorsport.com’s journalist Franco Nugnes claims that the reason behind Hamilton’s struggles with tyres during the US GP is down to FIA clampdown.

Before the start of the Grand Prix, the FIA requested that Mercedes close up the holes in the rear hub of the W09 with silicone in a bid to remove even the most subtle aerodynamic benefit.

The team was allowed to run the new wheel design introduced at Formula 1’s Belgian Grand Prix as it attempted to find an advantage over Ferrari.

The latest advance from Mercedes were aimed at both aerodynamic improvements and to help better manage the temperature of the brakes and tyres.

Ferrari asked why Mercedes was able to run with a rim design that featured a collection of holes that appeared similar to a concept that Red Bull was banned from using at the 2012 Canadian Grand Prix.

Under the then-article 3.15 of the Formula 1 Technical Regulations, teams were told that “any specific part of the car influencing its aerodynamic performance” must be “rigidly secured to the entirely sprung part of the car” and must remain “immobile in relation to the sprung part of the car”.

The rotation of the air in the hub was deemed to have been energising the airflow, which was illegal under the article, forcing Red Bull to change their design.

The FIA allowed the German marque to continue with the design saying it was not in breach of the regulations.

Ferrari then queried the matter again once it was revealed that the holes were also located inside the wheel hub, potentially creating a similar benefit as the previously banned Red Bull type. The Italians claiming they needed to ascertain if it were required to pursue its own solution or whether Mercedes had pushed things too far.

The FIA again concluded that Mercedes’ design has different intentions to the 2012 Red Bull system.

It seems now that the FIA have backtracked on their ruling, making Mercedes close up the holes before the start of the Grand Prix in Austin.

Perhaps this is the reason behind the inexplicable lack of pace of Lewis during his efforts to finish the race first, from a dominant pole position over the race distance?

Pole! That one was very important, it was close out there. We move forward to tomorrow where we’ll give it everything that we have 🇺🇸 @MercedesAMGF1 #Pole #USGP #TeamLH pic.twitter.com/89AN7GHBAy

— Lewis Hamilton (@LewisHamilton) October 20, 2018

Suddenly it seems that the Mercedes monster which seemed unbeatable from Monza onwards, has returned to being harsh on it’s rubber, evidenced by blistering of the rears during the US Grand Prix.

Couple this trait with Pirelli mandating tyre pressures to be increased by 1.5 PSI due to the anticipated high track temperatures of the Sunday, a significant increase of 10ºC, the Italian tyre maker’s instruction made in an effort to reduce wear and blistering.

Congrats to Kimi, he did a great job today out there. A huge thanks to the fans for always making this such a special place to race. We keep working and will push forward to the next one in Mexico #USGP #F1 @MercedesAMGF1 pic.twitter.com/otpMJS0DhS

— Lewis Hamilton (@LewisHamilton) October 21, 2018

Only then after the race was it learnt that Mercedes had to close the much contested hub and rim holes with silicone. A move that the FIA ​​had demanded, but without making any public communication.

And the result of that “small” change we have seen: the Mercedes team went into crisis with trying to manage the temperature of the rear tyres, even Valtteri Bottas right at the end of the GP had to give up fourth place to Sebastian Vettel in comeback because the Finn had finished his rears.

Nicholas Tombazis, FIA’s single-seater technical manager, avoided the opening of a litigation on limited illegality with the question being put to bed by the FIA demand. Had they not taken the stance, the holes and technique would surely be present on all cars next year.

Only Mexico will reveal just how big an impact the sealing of holes will be. Should we see more problems with rear tyres, perhaps we’re seeing another FIA stamping out the German’s version of a double battery loophole found on the Ferrari?