How did the asbence of the deceleration lap in Belgium lead to George Russell’s disqualification?

George Russell, Mercedes driver, lost his victory at the Belgian Grand Prix this Sunday just a few hours after the podium. The consequence of a strict weight rule in Formula 1. After an impressive race at Spa-Francorchamps, Russell, who had followed a one-stop strategy, was disqualified following technical checks after the race. While the strategy is undoubtedly a reason for his disqualification, mixed with the pressure exerted by his teammate in the final laps to overtake him, the real reason for his disqualification is the oversight of an important point: the deceleration lap is not done in Belgium.

The technical reason: a too light single-seater

The rule on the weight of single-seaters in Formula 1 is set by Article 4.1 of the F1 technical regulations which stipulates that « the mass of the car, without fuel, must not be less than 798 kg, at any time during the competition. » A clear rule that will change in the near future. After the race, Russell’s car weighed exactly 798 kg, but it is worth noting that the initial weighings are still conducted with the fuel. Once the fuel was drained to obtain the 1-liter sample required by Article 6.5.2, its weight dropped to 796.5 kg, which is 1.5 kg below the allowed limit.

Cause 1: A strategy that consumes too many tires

According to several pieces of information and as already analyzed by Craig Slater from Sky Sports, George Russell’s strategy of making only one pit stop during the Grand Prix could be the reason for this disqualification. Tire wear that he kept for many laps, combined with the absence of a second pit stop to change them, contributed to the car being under the regulatory weight.

Usually, Formula 1 teams precisely know the weight lost due to tire wear and plan their strategies based on the results. Russell, who was supposed to make two stops, opted for a single stop, which led to an unexpected outcome as the team did not have the necessary information to calculate the impact of this strategy. A Formula 1 tire, alone, without its rim and sensors, weighs between 9.5 and 11.5 kgs. This brings the total to around 40 kgs on the scale. Considering that these tires lose about 40% of their rubber, at the end of their life, the total mass of tires at the end of a Grand Prix can decrease to about 25 kgs, losing 15 kgs. George Russell’s tires, being used for 34 laps, therefore lost more mass than those of Lewis Hamilton with a two-stop strategy, or even Charles Leclerc, who on the same strategy had put on his hard tires, 4 laps later. This difference in strategy has major consequences as by consuming 40% of the rubber instead of 30%, the weight lost increases by an extra 4kgs. But that’s not the only cause. The absence of a deceleration lap at Spa-Francorchamps also played a role in the story.

Cause 2: Spa does not have a deceleration zone.

In general, after the Grand Prix is over, the drivers complete a full lap of the circuit to both thank the audience and the marshals, but mainly just to get back to the pit lane to the Parc Fermé. This allows them to pick up cold tire debris on their hot tires, which will then mix with the worn tires and add extra weight.

However, at Spa-Francorchamps, the longest circuit on the calendar, this slowdown lap would be too long. The drivers therefore return directly to the pit lane, which prevents adding these famous bits of rubber. According to our estimates, these track debris represent between 500g and 750g per tire. It is therefore possible to recover up to 3 kilograms on the F1 just during the deceleration lap, which could have allowed George Russell to easily comply with the weight limit.

Engineers have thus underestimated two important points: the lack of a deceleration tower and the impact of tire wear on a 34-lap strategy with the same tires. This lighter Mercedes can also justify why Lewis Hamilton, even with fresher tires, couldn’t overtake George Russell on the straight. 1.5 kgs in an F1 represent a few more kilometers per hour on the straight.