Understanding the anti-skid block, the board that produces sparks under F1 cars

Since 1994, all F1 cars have been equipped with an anti-skid block, often referred to as a “wooden board,” the introduction of which led to the adoption of new safety-focused regulations.

Since 1994, the humble anti-skid block has been installed under every Formula 1 car as an invisible safety net, a direct legacy of the fatal accident that claimed the life of Ayrton Senna. Placed under the chassis, this block ensures that the car never rides too low, preventing the sudden loss of control that can occur when the floor rubs against the track. FIA officials conduct random inspections after the race, and any violations, such as the disqualification of Charles Leclerc and Lewis Hamilton after the 2023 Austin Grand Prix, result in immediate exclusion.

The original “wooden board” was cut from Jabroc, a patented, heavily varnished beech wood composite. Some teams experimented with hybrids of exotic wood and resin, but this material has since disappeared from the paddock. Modern skid blocks are made from a non-flammable fiberglass thermoplastic. When heated, the material softens, allowing it to be molded; once cooled, it becomes both strong and flexible, offering properties similar to carbon fiber at a lower cost and with less rigidity. This change not only reduces the risk of fire compared to the 1990s, but also improves vibration tolerance, making the cars more maneuverable. FIA regulations stipulate that the density of the panel must be between 1.3 and 1.45 g/cm³ (or, in the case of a honeycomb, the top 0.5 mm must be between 1.3 and 1.65 g/cm³, while the rest must remain between 1.3 and 1.45 g/cm³).

Securing the panel is an exercise in durability. Early versions were bolted down with tungsten fasteners, an exceptionally heavy metal whose name means “heavy stone” in French. The extra weight prompted a gradual shift to titanium, a lightweight alloy prized for its strength. Teams also apply a semi-permanent adhesive, a practice tolerated by the FIA even though the regulations only require the use of predefined fasteners. These titanium bolts are responsible for the characteristic sparks that fly when the floor of a car comes into contact with the asphalt.

The technical regulations precisely define the dimensions of the floor. It must be 300 mm wide (±2 mm) and extend from the front of the front axle to the rear axle line, with a front edge cut at a maximum angle of 30° and a depth of 8 mm, and a rear chamfer of 200 mm at the same depth. New boards are 10 mm thick; after a race, they must retain at least 9 mm, allowing for a maximum wear of 1 mm. The thickness is not measured around the perimeter, but at four holes in the center, as specified in the RV-PLANK document. Teams can add up to four additional 10 mm holes for mounting, typically using two (one at the front and one at the rear) to secure the board, while the additional holes are reserved for the accident data recorder bolts. In addition to the measurement holes required by the FIA, technical stewards may also inspect the mounting holes. None of these may be thinner than 7.5 mm at the end of the session. Unlike the measurement holes, the mounting holes have an additional tolerance of 1.5 mm, as the mounting points are supposed to be the least flexible and therefore most susceptible to damage. “The minimum wall thickness between an internal mounting hole and the outer limits of the protective plate must not be less than 7.5 mm.” If this thickness is not met after a race or qualifying session, the driver may be disqualified.

Penalties are regularly imposed Over the last two decades of the championship, the rule regarding the wooden plate has been broken on several occasions. Michael Schumacher – Just a few races after the introduction of the wooden plate, the first penalty was imposed. At the Belgian Grand Prix, Schumacher, then racing for Benetton, was disqualified for excessive wear. He had hit the kerb at the Pouhon corner, aggravating the wear, and was stripped of his victory even though he had crossed the finish line first. Jarno Trulli – On September 30, 2001, when F1 moved to the Indianapolis Motor Speedway, Italian driver Jarno Trulli was initially disqualified. The stewards ruled that the Jordan-Honda was in breach of ground clearance regulations due to excessive wear. The team appealed, and the FIA International Court of Appeal overturned the decision, reinstating Trulli to fourth place. Lewis Hamilton and Charles Leclerc – Twenty-two seasons after the last suspension, the FIA again disqualified drivers for excessive wear, this time at the United States Grand Prix in Austin. The Circuit of the Americas was criticized for its bumpy surface, and two of the four cars inspected were found to be in violation of the rules. Charles Leclerc and Lewis Hamilton both left the 2023 race empty-handed. In motorsport, the wooden board has become ubiquitous. Today, any vehicle participating in an FIA-regulated event must be equipped with this anti-skid block in order to be allowed to race.