Why do F1 cars spark? The plank under the floor and titanium skids

Where do the sparks come from?

From under the floor. A plank runs along the middle of the car there, with metal skids set into it. When the car bottoms out, the skids scrape the track surface and throw up sparks. In 2014 the FIA Race Director, Charlie Whiting, put it this way: the plank is a long wooden part, and the skids are pieces of metal set into it.

Sparks don’t always come from the plank. In the third practice session of the 2024 Canadian Grand Prix, Max Verstappen brushed the Wall of Champions, and the sparks flew from his right rear wheel.

What is the plank and why do F1 cars have one?

The plank is a strip running along the middle of the floor. According to Formula 1, it became compulsory in 1994 to stop cars running too close to the ground. It was one of the measures taken after the deaths of Roland Ratzenberger and Ayrton Senna at Imola. The plank arrived for the 1994 German Grand Prix, and the whole car had to be raised. The other measures of that season are collected in the article on Senna’s death.

This is how the plank is built under the 2026 technical regulations:

• a new plank is 10 mm thick, with a tolerance of 0.2 mm;
• after wear it must still be at least 8 mm thick;
• the thickness is measured around the edges of three holes 34 mm in diameter;
• the team chooses the material, but its density is set at 1.3–1.45 times that of water;
• the plank may be made of no more than three pieces, and the front one must be at least 900 mm long.

The rule is simple: a plank thinner than allowed is a breach of the technical regulations. In 2025 the limit was stricter, at least 9 mm.

Why are the skids titanium?

Because the regulations have required it since 2015. Before that, the skids were made of a heavy and very wear-resistant metal, and teams fitted them around the holes where the plank’s thickness is measured.

The FIA gave three reasons for switching to titanium, in Whiting’s words at a briefing on 3 July 2014:

1. It is safer: titanium skids are about a third of the weight of the old ones. Pieces of the heavy metal that came off were dangerous: at Spa, bits lying in a kerb had already caused two punctures.
2. Titanium wears 2–2.5 times faster, so cars would have to run a little higher and couldn’t scrape their floors along the track as hard as before.
3. There would be a lot more sparks, which, as Whiting put it, some people would find more spectacular.

And so it proved. In November 2015, Formula 1 wrote that races under floodlights, such as Singapore and Abu Dhabi, had become even more spectacular thanks to the new rules on skids. Evening and night races are covered in the night races article.

Since 2026 a metal skid has been compulsory around the front hole and optional around the middle and rear ones; before that, all the skids were up to the team. The titanium is Ti6Al4V and the steel is 17-4PH, and the FIA sets out which material to use at each event in a separate document.

Why does the car scrape the track?

Because teams run it as low as possible. In 2022 ground-effect cars returned to Formula 1, and according to Formula 1 their floors work best when the car runs as close to the track as possible. Some teams then struggled with cars that bottomed out and bounced. At the same time, as Formula 1 puts it, the plank is exactly what limits how much a car can use ground effect. How the floor and wings create downforce, and how it holds a car back on the straights, is explained in the top speed article.

Bumps wear the plank down too. After the 2023 United States Grand Prix, the stewards named the bumpy track and the sprint format as the causes of the excessive wear. On a sprint weekend the teams had one practice session, after which the car went into parc fermé: the ride height could no longer be changed without starting from the pit lane. Mercedes added that they hadn’t run with a race fuel load in that session.

What gets a car disqualified?

A plank worn thinner than allowed. The standard penalty for breaching the technical regulations is disqualification, and, as the stewards in Austin pointed out, it is up to the team to keep the car within the rules at all times. After the race the FIA checks the planks on a few selected cars. According to Formula 1, there isn’t time to check every car, and the random checks are meant to deter teams from breaking the rules on purpose.

In Austin in 2023, Lewis Hamilton finished second and Charles Leclerc sixth, and both were excluded from the results. Ferrari admitted that the plank had been a few tenths of a millimetre under the limit.

Every disqualification for plank wear in the f1db database, as of 29 September 2026:

In total there have been eight such disqualifications since 1994, and six of them came in 2023–2025, the seasons of the ground-effect cars. The other penalties in F1 are covered in the penalties article.