Charles Leclerc’s disqualification: Pirelli explains the impact of tire wear on the race. Mario Isola quantified the impact of tire wear and marbles collected at the end of the race.

A combination of factors. This is how Frederic Vasseur analyzed Charles Leclerc’s disqualification in China for the minimum weight infraction, citing among other things the liter of water lost due to a bottle leak and tire wear during a race that switched from a two-stop to a single-stop strategy. Mario Isola also commented on this, providing numbers on the typical weight loss from tires during a race and the weight that can be recovered with marbles during the in-lap.

The Weight of Wear
The tire issue was at the center of the latest episode of *The Tech Formula*, a new in-depth talk show created to analyze and explain the technical aspects behind what happens on track, such as Ferrari’s double disqualification in China. The program offers insights from experts and various guests, including engineers and paddock personalities, with Mario Isola as the most recent guest. The Pirelli Motorsport director addressed a general curiosity, quantifying the mass that tires lose during a race. This discussion is related to Ferrari’s Charles Leclerc’s minimum weight infraction after a race that turned into a one-stop strategy.

“It depends on the circuit and the amount of wear,” explains Mario Isola. “A set of tires, however, can lose more than 2 kg during a race. This is a well-known number for the teams. In such a competitive environment, with 20 cars within 1 second, everyone looks at the smallest detail to try to improve performance.” The words of the Pirelli Motorsport director echo those of Frederic Vasseur, who described the disqualification incident as a reflection of the risks that every team must take in such a tight grid. Carrying an extra 2 kg, for example, can cost about half a tenth per lap in qualifying, which over 60 laps equals 3 seconds.

The Tools Available
The Pirelli Motorsport director also spoke about the models available to teams to predict the remaining tire mass in real time: “It is possible, they can make an estimate. They can use these simulations and plug them into the equations to calculate the minimum weight at the end. They understand this thanks to the stabilized temperature of the tire carcass. As the tire wears, the temperature drops, and from that, they understand the level of wear.” A worn tire with less material, in fact, deforms less, generating less heat and cooling down. However, as Mario Isola himself pointed out, even though the team can estimate the remaining weight, they have no way to react unless they make an additional stop.

One practice that teams use to recover some of the lost weight is collecting marbles, the rubber bits that accumulate outside the racing line, which drivers can collect during the in-lap. Mario Isola provided an order of magnitude for the weight gained: “We don’t have an exact number. You can recover some hundred grams from the rubber marbles and debris. We’ve seen some drivers even go off track to collect more debris or other materials. I would say you can recover about 1 kg per tire set, but that’s just an estimate. However, it is impossible to fully compensate for the weight lost due to wear with this.” – the Pirelli boss concluded.