F1 skid blocks explained: Why were Hamilton and Leclerc disqualified from United States GP?

Yara Elshebiny
Monday 23 October 2023 11:15 - Updated: 15:31

What is the skid block that caused disqualifications for Lewis Hamilton and Charles Leclerc in Austin? Let's find out.

Hamilton and Leclerc were both disqualified from the 2023 United States Grand Prix in Austin, losing their respective P2 and P6 finishes after a post-race random check on four cars.

The check found the skid blocks on the Mercedes and Ferrari to be excessively worn out, meaning their planks did not conform to F1's Technical Regulations.

READ MORE: Hamilton and Leclerc were disqualified in late F1 drama after US Grand Prix

What are skid blocks in F1?

Skid blocks, also known as skid plates or skid pads, are planks placed underneath every F1 car from front to back and are made of glass-reinforced plastic called permaglass.

They were introduced in 1994 as a safety measure following the tragic deaths of Ayrton Senna and Roland Ratzenberger, in order to maintain a minimum ride height and prevent cars from being too low to the ground.

The skid blocks, which were made of wood many years ago, also play a crucial role in protecting the floor of the car when it goes over kerbs or touches the ground at high speed.

What are the skid block rules?

According to F1's technical regulations, the plank must be a centimetre thick. If the plank wears down by more than a millimetre, the car breaches the technical regulations, leading to disqualification.

Article 3.5.9 e) of the 2023 F1 technical regulations states:

"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."

How is plank’s thickness measured?

After a race, officials randomly select cars to carry out checks to ensure they comply with regulations.

This is done by measuring the four 50mm diameter holes and the two forward 80mm diameter holes that are drilled into the car's plank and titanium plates.

The six holes are 10mm deep. If a wear of over 1mm is found during the checks, the driver will be disqualified automatically.

Who was the first to be disqualified for illegal skid block wear?

At the 1994 Belgian Grand Prix, Michael Schumacher became the first driver to break the newly introduced skid block rule.

The German legend's victory in Belgium was short-lived as the skid block on his Benetton was found to have worn down excessively, resulting in his disqualification from the race.

Why do F1 cars spark?

The sparks come from titanium plates attached to the plank. When the car bottoms out, especially on straights when the downforce is strong, these parts hit the ground, creating a bright and fiery spark behind the car, which is a thrilling sight for F1 fans.

READ MORE: What is downforce and why is it important in Formula 1?