Ferrari disqualification – Charles Leclerc loses 20 kg, 10 of them just from tires: what went wrong. Ferrari suffered a terrible double disqualification of the SF-25 cars in China with Charles Leclerc and Lewis Hamilton.

Ferrari suffered a terrible double disqualification of the SF-25 cars at the 5.451-kilometre Shanghai International Circuit, with Charles Leclerc and Lewis Hamilton. A situation that is hard to swallow, because the Italian team, until a month ago, was proudly declaring the achievable goal for the 2025 Formula 1 racing season, which was to win at least one of the two world titles. After two Grands Prix, you cannot throw in the towel, that is clear. However, a quick push on updates is needed, in order to raise the understanding of the car and throw itself back into the fight with McLaren. In the meantime, as we have more time off with no Grand Prix scheduled for this weekend, let’s revisit Charles Leclerc’s case in China with further technical details.

After the race, all cars undergo technical checks by the FIA, where they are weighed. Additionally, there are random checks concerning the conformity of some parts. The document from the International Federation that describes everything in detail is called “Race Scrutineering,” published for every Grand Prix on the official website. The Shanghai race showed a development that widely surprised the technicians.

We are referring in particular to the fact that most cars finished the race with a single pit stop. During the long final stint of about 30 laps, tire wear was at its maximum, bringing out a significant issue related to the minimum weight. According to the regulations, once the fuel is removed, each car must not weigh less than 800 kilograms once it crosses the finish line.

In Charles Leclerc’s case, when the technicians removed the fuel from the tank and added half a kilo for the damage to the front wing, the weight was 799 kilograms, which is one unit below the minimum allowed. To better understand how this parameter is managed by teams, it is important to clarify an aspect that is sometimes overlooked, but is crucial for making the calculations correctly.

Stress on the components of very important. Each car loses approximately 20 kilograms of extra weight due to fuel consumption. All the mechanical parts, such as gearbox gears, clutch or brake discs, and fluids like coolant or lubrication oil, wear down. Every gear change or braking creates friction between components, leading to wear. Some of these particles are captured in the oil, but most disperse into the air and reduce the car’s weight.

This concept is not easy to understand. Often, people don’t focus on the fact that every component of the car is optimized at its best and undergoes maximum stress during the 300 kilometers of the race. Even regular cars wear down these components, but over a distance that is 80 to 100 times greater, because the unit stress they endure is significantly lower, as they are not racing.

In mathematical terms, we can say that each element has an “X” amount of energy that can be used during its life cycle. In F1 cars, this value is reached with a few events (such as braking) of very high intensity. In contrast, in road cars, energy is accumulated through many factors of negligible intensity. The pre-race simulations have a maximum error of about 1 kilogram.

Without going into too much detail, the element that most troubled Ferrari’s engineers and technicians concerns the tires. The outer part of the tire, the tread, has a thickness of about 3 millimeters, which wears down to produce grip. If we consider the 4 tires, the total volume of tread available is approximately 10 cubic decimeters, equivalent to 12 kilograms, if we consider the tire density used in their construction.

As one might easily guess, this reference must be considered to avoid being underweight at the end of the race. For this reason, drivers go outside the ideal racing line after crossing the finish line, performing what is known as a “pick-up.” The hot tires, in contact with the marbles outside the “racing line,” cause them to slightly melt and stick to the tires.

It should be noted that the Monegasque driver was immediately reminded after crossing the finish line to perform the pick-up. The order of his Ferrari race engineer Bryan Bozzi is standard for every Grand Prix. Charles Leclerc deliberately went off the racing line in turn 1, then placed the right front tire on the grass on the longest straight of the track and finally did the same with the left front tire just before stopping in the parc fermé, just like Max Verstappen.

Lewis Hamilton also did it, making a small excursion off-track, but without going onto the grass, unlike his Maranello teammate. This operation is quite common, and there are no predefined areas to perform it, which are studied in the briefing before the race. The choice is left to the drivers. However, it is indicated whether it is better to do it just before stopping the car to avoid cleaning the tire too much after getting it dirty on the grass.

Moreover, as we saw George Russell and Max Verstappen do on Sunday, Charles Leclerc also went onto the grass, off-track, to increase the weight of the tires and thus the car’s weight. The final stint was so long that it did not help Ferrari’s engineers in managing the weight. Everything is based on simulations made by the Maranello engineers and technicians before the race, where, for each lap, the amount of fuel, tires, or accessories the car “loses” is estimated.

They also consider the number of gear shifts, braking events, and the average engine revolutions, as well as the amount of energy required by the tires to produce grip, keeping in mind that the car lightens over the course of the laps and, consequently, the load levels that need to be supported change. All of this aims to finish the race with a weight of 801 kilograms and an error margin of about 1 kilogram.

Following these considerations, the Italian engineers were caught off guard by the only variable they had not considered. Simply changing the tires for a second stint would have recovered more than 10 kilograms of weight with a new set. Additionally, at the end of the race, the Hard compounds had worn more than the simulations had predicted, further reducing the weight. This was also because, with Charles Leclerc, a second pit stop had been anticipated, which led to pushing more than necessary in the first part of the stint.

The Shanghai racing circuit is very demanding on component wear, as there are 3 sharp braking zones and the engine operates at high thrust levels. On top of that, we must consider that Charles Leclerc’s race was unusual. For many laps, the Ferrari driver was in Lewis Hamilton’s dirty air, forcing the cooling systems to work harder and consuming more coolant fluid.

The Monegasque driver then had to defend himself from Max Verstappen’s attack in the final part of the Chinese Grand Prix and was therefore unable to save fuel. Ferrari’s misjudgment will certainly help the Maranello team refine their simulation parameters for the upcoming races. The entire sensor system that estimates the car’s weight during the race will also be reviewed. The goal is to avoid further embarrassing moments like the one in China.