F1 MATHS: What does the data tell about Leclerc's disastrous final stint in Hungary?

F1 Grand Prix, GP Hungary, Hungaroring

Following his sensational lap in Saturday's qualifying which saw Charles Leclerc claim a shock pole position for Ferrari, the Monegasque endured a heartbreaking result at the Hungarian Grand Prix despite his impressive pace during his first two stints of the race. F1Technical's senior writer Balazs Szabo delivers his latest analysis in his column branded as F1MATHS.

Ferrari endured mixed emotions in Saturday’s qualifying at the Hungaroring. Lewis Hamilton failed to secure anything better than a P12 on the grid after struggling for pace in constantly-changing weather conditions.

On the other side of the garage, Charles Leclerc also looked to uncomfortable behind the wheel of his SF-25, albeit he progressed into the final part of qualifying. With a storming lap, he grabbed pole position on a track where he never really felt himself competitive.

Come the race, the Monegasque had a great start to maintain the lead into Turn 1. During his first stint, he looked very competitive and was able to build up a margin from his closest rival Oscar Piastri.

Although he appeared to be strong during his second stint as well, his pace unexpectedly faded in the last segment of the Mogyoród race which saw him fall back to P4, ending a disappointing day at the Hungaroring.

After taking the chequered flag at the Hungaroring, the Monegasque suggested that an issue with his chassis caused his sudden loss of pace in the final stint of the 70-lap Hungarian Grand Prix.

"No, it was a one-off. We need to look at it for it to never ever happen again, because the car was just undriveable. But I don't think it's something that we'll have anywhere else again," added Leclerc.

Ferrari team boss Fred Vasseur echoed Leclerc's words regarding the mysterious technical issues that might have robbed the Monegasque from achieving his first F1 victory of the season.

"We have to investigate if we have something broken on the chassis side. At one stage I thought that we would never finish the race, that we were lucky to score points for fourth. It's surprising, because if we had known before [we would have solved it]," noted the Frenchman.

However, Mercedes driver George Russell, who managed to get onto the podium thanks to Leclerc's issues, suggested that the Ferrari man actually had another issue.

The Briton insisted that Ferrari might have had fears about plank wear which forced them to manage the issue by increasing tyre pressure and running a specific engine mode to care the plank underneath the SF-25.

"The only thing we can think of is they were running the car too low to the ground, and they had to increase the tyre pressures for the last stint.

"Because they were using an engine mode that was making the engine slower at the end of the straight, which is where you have the most amount of plank wear," Russell told Sky Sport F1 after the Mogyoród race.

The Scuderia already had issues with the plank wear as Leclerc's team-mate Lewis Hamilton was disqualified in China for excessive plank wear.

The data provided by F1DataAnalysis shows that the eight-time Grand Prix winner was clearly quicker than championship leader Oscar Piastri in the opening stages of the race. It was a surprise given McLaren's superiority in terms of race pace, but Leclerc looked incredibly consistent and confident behind the wheel of his SF-25 at the start of the 70-lap Mogyoród round.

The Monégasque quickly built up a gap from Piastri, with 3.022 seconds having separated them at the end of Lap 8. However, when he started the following tour, his race engineer Bryan Bozzi asked him to switch his power unit into FS1 mode.

When comparing Leclerc's performance on Lap 8 and 9, the data clearly shows that he lost valuable top speed down the main straight and also on the uphill section into the Mansell-corner (Turn 4).

When Russell assessed the situation, he suggessted that teams only opt to such an engine mode which is branded as FS1 at Ferrari when they are eager to reduce top-end speed in oder to prevent downforce peaks pushing its floor down onto the track.

Interestingly, Leclerc hardly lost anything to Piastri after changing the engine more. When the McLaren man dived into the pits for his first tyre service, he was 2.489 seconds away from the Ferrari driver. It means that Leclerc lost 0.533 seconds over the stretch of these 10 laps despite switching into a lower engine mode.

With Piastri having pitted a lap earlier, the gap reduced to just 1.266 seconds as the Australian was able to exploit the grip advantage on his first lap.

On the following laos, the gap between them showed very little fluctuation, and it was exactly 1.645s when Leclerc came into the pit lane for his second stop. Ferrari deliverd another faultless, sensational tyre change that lasted only 2.0 seconds.

Piastri pitted six laps later, and rejoined the track 5.327 seconds behind Leclerc. It was not surprising to see Piastri lose around four seconds over the stretch of these six laps as Leclerc enjoyed the additional grip of his fresh Pirelli hard tyres.

In fact, the Monegasque was able to raise his pace by a second per lap compared to his last laps on his previous set of hards – 1m21.629s on Lap 39 versus 1.20.688s on Lap 42. However, his rivals – Piastri and Mercedes driver George Russell – found 1.5 seconds on their fresh C3 tyres, whereas it was only a second in case of Leclerc, who then started to lose even more pace from Lap 50.

Interestingly, from Lap 50 onwards, the Monégasque was slower than during his second stint despite carrying around 28 kg less fuel on board which is equivalent to a loss of 7 tenths per lap around the Hungaroring.

While Ferrari refused to offer an explanation for the issue, Leclerc was clearly managing a technical issue in the final stint as he lost his very competitive pace from the first two stints on the medium and the hard tyres.

As Leclerc was heard on the radio that his car “is just undriveable. Undriveable. It will be a miracle if we finish on the podium,” after his car looked very well balance across the first two stints on two different compounds, Russell’s explanation regarding Ferrari’s decision to increase the tyre pressures for the last stint might be true.

Following his sensational performance in qualifying and in the opening two stints of the race, the Monegasque understandably cut a dejected figure after the Hungarian Grand Prix, claiming that “this was an issue and it’s an outlier. It shouldn't ever happen again. But I’m still very disappointed.”

“I don’t think we are going into the second half of the season thinking that we can win anywhere, and that’s what makes the frustration even bigger because we knew that this was probably the one opportunity of the season and we had to take it. But unfortunately with this issue we couldn’t do much,” Leclerc concluded.