Technical analysis of Ferrari SF-24 and Charles Leclerc’s technical issue in 2024 F1 Bahrain GP. Bahrain GP: technical analysis of Ferrari SF-24 and Charles Leclerc's problem at the Sakhir circuit.

Scuderia Ferrari, especially with Charles Leclerc, is not satisfied with the results in the first round of the 2024 Formula 1 season, the Bahrain Grand Prix. A podium finish for the SF-24 is not enough. More was expected, and perhaps, under different circumstances, things could have gone better. This is because, with two red cars immediately behind Max Verstappen on the starting grid, the pressure on the Dutchman would have been greater. Not to mention the problem faced by car number 16, which effectively compromised Charles Leclerc’s performance at the Sakhir circuit, leaving him very angry and disappointed at the end of the race.

The opening race of the 2024 F1 championship didn’t bring many surprises: Max Verstappen crossed the finish line first, with a significant lead over his teammate Sergio Perez and the two red cars. Carlos Sainz completed the podium, ahead of a disappointed Charles Leclerc, who had to deal with brake issues that, as mentioned, influenced the Monegasque driver’s race. The Grand Prix broadly reflected the values expressed during the pre-season testing session.

We witnessed many lock-ups during braking, with cars, in certain situations, wandering off the track. This is a fairly common occurrence in the world of Formula 1, generally happening in the early stages of braking. However, on Saturday, we often saw so-called “lock-ups” in the final stages of braking, creating quite a headache for drivers, especially for Charles Leclerc.

Let’s try to provide a technical interpretation of these situations, focusing on why lock-ups occur, what causes them, and how drivers can intervene to prevent them. First and foremost, a lock-up occurs because the driver applies too much braking force to the wheel, which ends up completely blocked by the calipers. This creates a “skidding” of the tire on the track surface, producing smoke.

The consequences are quite deleterious for the tires: the temperature tends to increase rapidly due to increased friction, and the tire surface tends to wear more in the sliding portion. Moreover, the compound slightly deforms, losing its perfect rounded shape, causing instability and harmful vibrations for the handling. The headaches vary from harmless lock-ups at low speeds to the so-called flat-spots, typical when locking up at high speeds. In some cases, especially in the latter, the driver may be forced to replace the set of tires, as the oscillations caused by the flattened wheel can create a serious safety issue.

So, what can the driver do to prevent lock-ups? There are driving and mechanical adjustments that help avoid them. Firstly, the immense aerodynamic load produced by the car is used to decelerate more quickly without locking up. If you observe a typical telemetry graph of F1 brake data, you’ll notice an initial peak followed by a gradual release of braking pressure until it is completely released.

This technique is primarily used because the friction force (and the tire grip) is proportional to the vertical force pressing the car to the ground. Consequently, as the car decelerates, downforce decreases, and thus the tire grip. If the driver does not adjust the brake force accordingly, there is a risk of exceeding the grip force, and the tire locks up.

In the event that this limit is mistakenly exceeded, the driver tends to release the brakes instantly, going long into the braking zone. This is done to “save” the tire, which will still be able to roll optimally. It goes without saying that such a scenario can occur when there is enough space. Now, let’s move on to the small mechanical changes that can be made directly from the steering wheel.

The first, seemingly simple, is the brake balance adjustment. Watching the onboard footage at Sakhir, you can see that the drivers constantly adjusted this parameter depending on the corner to tackle. In slow corners, preceded by strong braking, the brake balance was moved to the front, following the weight transfer that tends to load the front axle due to inertia. As mentioned earlier, a more loaded axle has more grip and, consequently, avoids lock-ups.

Typical brake balance values during braking are around 57-58%. Rarely does it go beyond this range because configuring a setup too “rearward” risks locking up the rear, with unpleasant consequences. On the contrary, in medium-fast corners, where less time is spent on the brake, a neutral balance or less front-oriented is preferred. In these cases, the brake balance can reach a minimum of 55%.

If brake balance is a static parameter, another regulation helps drivers in braking dynamics, called brake migration. This system, made possible by Brake-By-Wire, allows adjusting the brake distribution based on the pressure applied to the pedal. Specifically, based on the chosen value, Brake-By-Wire releases the brake percentage on the rear more or less rapidly, favoring the front.

The correct adjustment, made through small levers on the steering wheel, ensures that the car is in the best possible conditions to tackle the corner, maximizing grip, speed, and minimizing the risk of harmful lock-ups. After this overview of the theory of lock-ups and possible remedies, we can finally focus on what we saw in Bahrain, with a particular eye on the challenging situation experienced by Ferrari’s Charles Leclerc.

Ferrari SF-24: Front Axle Temperature Imbalance Affects Charles Leclerc’s Race

Looking at the race, most lock-ups were observed at low speeds near turn 10. The challenging configuration of this corner requires drivers to brake while turning the steering wheel, lightening the left front, which becomes very easy to lock up. The protagonists of these unpleasant incidents were, in particular, Charles Leclerc, Carlos Sainz and George Russell.

Beyond the temperature issues suffered by Charles with the brakes and George with the power unit’s cooling system, without data from the teams, it’s challenging to find a single explanation for the numerous lock-ups. However, one factor unites the mentioned drivers: they all found themselves having to face the first race with completely revamped cars. Ferrari, for example, substantially modified the aerodynamic configuration, while Mercedes, in addition to the philosophy of the side pods, also overhauled the rear suspension scheme.

Most likely, the different shapes of the SF-24 and W15 have also changed the references in terms of behavior, forcing drivers to look for new ones. This lack of affinity with the cars, moreover, becomes even more apparent in extreme situations, with less downforce to cover the gaps in feeling, such as heavy braking or more challenging turns. It should not be surprising, therefore, that in the strong deceleration of turn 1 or the tricky turn 10, drivers arrived with smoking tires.

With all this said, let’s get to the point. As we know, from the very early stages of the race, car number 16 suffered a clear problem with the braking system. The temperatures on the front axle were significantly imbalanced between the brake discs. When such an issue occurs between the front and rear of the car, being able to read the issue is much more factual, and through different configurations, the problem can be largely resolved.

On the contrary, when the imbalance occurs on the same axle (front or rear, so on the individual wheel compared to the other in front or behind), resolving the issue is not possible. The trouble experienced by Charles Leclerc caused the car to tend to slide to the right during braking. A context that, in turn, complicates another factor.

The different stress on the tires, which suffer different temperatures, modifying the correct working range of the warmer left-side tire.

For this reason, the Monegasque had to manage a different degree of heat on the front of this tire, with all that entails. We are referring to the sweeping turns where he automatically had to slow down to avoid overloading the tire. In all this, we must add one more thing: the oversteering behaviour of Charles Leclerc’s SF-24 increased. Before making the pit stop and switching to the Hard tires, the Ferrari driver didn’t understand what was happening on the radio.

Once the set of Soft tires he started the race with was set aside, the words of the Ferrari driver were iconic: “there was something wrong with this set of tires… it’s like the front tires went crazy.” Some people have suggested that debris might have clogged the brakes. This is an incorrect hypothesis since, during the tire change, the mechanics didn’t even approach the brake duct, simply changing the tires.

Now, let’s move on to Fred Vasseur’s words at the end of the race. The French manager enters the post-race communication between Charles and his race engineer Xavi Marcos with a strong tone, just as the Spanish engineer was trying to explain the reasons related to the problem. Fred essentially stops the conversation abruptly, using a short, decisive, and quite emblematic phrase within the context: “We’ll explain later.”

Considering the various factors analyzed, the most likely possibilities could be three: an assembly error by the mechanics related to the braking system, a “simple” malfunction of the system due to a component breakage, or a manufacturing issue. In all cases, we are talking about a situation that could have been strongly avoided, which, in fact, infuriated Charles Leclerc, disappointed by yet another race outcome affected by technical problems. What happened will be investigated by Ferrari and Brembo to accurately determine the causes of the annoying issue.

Source: Andrea Mauri and Alessandro Arcari for FUnoanalisitecnica