F1 Tech | How Ferrari's extreme set-up exploited the limitations of the SF-25

15:46, 09 Sep

Updated: 16:24, 09 Sep

byFrancesco Bianchi

The Italian Grand Prix has been a difficult one for Ferrari, with Leclerc and Hamilton who finished the race in P4 and P6 respectively, despite the positive start to the weekend. The car was highly unbalanced and difficult to drive, due to the extreme set-up chosen, which highlighted some design limitations of the SF-25. Let’s try to understand the details that emerged.

Monza has always been a special circuit for Ferrari, not only because it’s their home Grand Prix, but especially for the history that this track has. Last weekend, to honour Niki Lauda’s first championship with Ferrari in 1975, the team introduced a completely new livery on the SF-25, to celebrate this historic event.

This wasn’t the only innovation of the weekend, as the team also brought two different rear wing versions and a modified front wing to better suit the SF-25 to the Temple of Speed's layout, which requires an extremely low downforce set-up.

For what concerns the rear wing, the team tested the two different versions during FP1: as highlighted in the drawing below, Hamilton used the more loaded spec (left-hand side of the drawing), which was characterised by a DRS flap with a longer chord, to make the DRS effect more powerful when the system was activated.

Moreover, this solution guaranteed more downforce on the rear axle, making the car more stable under braking and improving the rear tyre management on high fuel load, despite producing a bit more drag. This rear wing version was the same one used by both Leclerc and Sainz in 2024.

On the other hand, Leclerc’s car was fitted with the even lower downforce version (right-hand side of the drawing), characterised by a trimmed trailing edge of the DRS flap (orange arrow and line), to make the car even faster in the straight-line, a crucial aspect around Monza.

On the other hand, this rear wing choice could have made the car too unstable in the braking phase, as well as in traction phases, resulting in a significant loss of lap time.

Both drivers used the same single-element beam wing designed for low downforce tracks: as highlighted by the pink arrow, this airfoil was characterised by a decent chord in the central portion and its length decreased as it approached the endplate, to reduce drag (pink arrow).

SF-25's rear wing comparison in FP1

For what concerns the front wing design, it showed a different design of the top flap as well, to balance the low downforce rear wing used on both cars: as highlighted in the drawing below, the version used in Monza was characterised by a trimmed top flap, which featured a very reduced chord compared to the version used in Zandvoort (green arrow). The goal of this design was to reduce the downforce generated on the nose of the car, making the car more balanced and faster in the straight-line.

SF-25's front wing used in Monza vs. the version used in Zandvoort

These technical choices seemed to immediately pay dividends during the first hour of practice: Hamilton seemed very confident with the car, completing many laps on the medium, throughout which he kept improving as the fuel burnt out.

Eventually, he even managed to set the quickest time of the session on the soft, proof that the additional downforce provided by the higher downforce rear wing gave him more confidence in the braking phases and through the high speed corners of the track, like Ascari and Parabolica.

However, hoping to take advantage of the track evolution throughout the weekend, Ferrari’s engineers made a logic but aggressive set-up choice: both cars were fitted with the extreme low downforce rear wing used by Leclerc in the morning, characterised by the trimmed DRS flap (orange arrow), to maximise the potential of the car in the straight-line, an aspect where they excelled also compared to McLaren and Red Bull.

Moreover, the team kept the same asymmetrical cooling louvres design used in FP1 on both cars: as highlighted in the drawing below, the SF-25 featured three scales on the left-hand side (one bigger and two smaller), while on the right-hand side there was only one big cooling exit, a choice related to the placement of radiators and intercooler inside the engine cover.

SF-25's rear wing chosen for the Italian Grand Prix

The aggressive set-up choice, however, didn’t seem to pay off throughout the second hour of practice: the SF-25 looked much more nervous in all braking zones and high speed corners, due to the instability caused by the lower level of downforce.

The higher top speed and higher engine modes compared to FP1 allowed Leclerc to eventually set the second best time on the softs in the qualifying simulation, only 0.083 seconds behind Norris in P1, but the real limitations imposed by this extreme set-up emerged as soon as fuel was loaded on the car for the race pace simulations. With high fuel load, Leclerc went off both at Lesmo 2 and Ascari on the soft tyre, proof that it had become even harder to keep the car on the tarmac.

At the end of the sessions, talking to Sky Sports F1, both drivers declared that the car was very difficult to drive, with Leclerc saying that: “It was difficult with both little and a lot of fuel, but we are fast.” And Hamilton underlining that he felt more comfortable with the set-up chosen in FP1: “FP1 went well, it was a good session. Then in FP2 we made some changes to the car, but it got worse.”

The aggressive set-up made the SF-25 even slower

Despite the drivers’ complaints, the team decided to keep the same rear wing for Saturday, hoping that the track’s evolution and the fine tuning work done during Friday night would have made the car a bit easier to drive.

Leclerc’s good performance in FP3 seemed to confirm that the car had improved compared to the day before, but the performance in qualifying brought the team back to reality: the SF-25 was extremely difficult to drive through the high speed corners and very difficult to stop at the first and second chicanes, with Leclerc and Hamilton who couldn’t do better than P4 and P5.

The extreme set-up highlighted two big design limitations of the SF-25:

The lack of downforce generated from the Venturi channels: Adopting such an unloaded rear wing, the team decided to lower the car down even more to partially compensate for the loss of downforce, recovering some of that load from the Venturi channels. The problem for Ferrari was that the floor wasn’t generating enough downforce to make the car stable and quick in the high speed corners, resulting in a very unstable car through those sections. Particularly significant was the comparison with Red Bull: the Milton Keynes team made the same choice, but car’s the floor was able to perfectly compensate the loss of downforce, making the RB21 fast in the high speed despite an aggressive wing choice.
A very weak mechanical set-up compared to Red Bull and McLaren: the SF-25, in fact, was also very slow through the slow speed corners and chicanes where mechanical grip is required. This proves that, despite the revised rear suspension introduced in Spa-Francorchamps, the team did a poor job from this point of view, especially compared to their direct rivals.

Lewis Hamilton during the Italian Grand Prix

Team principal Frederic Vasseur confirmed these impressions to Sky Sports F1 after qualifying: "We made an aggressive choice by going so light [in terms of downforce], which is why we're suffering more in the corners with less downforce. We're suffering especially at Ascari and other corners. But we know that tyre management will also be at the limit.”

That’s exactly what happened during the race on Sunday: the lack of downforce and mechanical grip made tyre management even more difficult with high fuel load, as both Hamilton and Leclerc struggled to even put the tyres into the right working window.

Particularly significant were Leclerc’s first few laps: his rear tyres massively overheated due to the high stress put on them when battling against Piastri and took the Monegasque several laps to bring them back in the right working window.

This inevitably translated into a big time loss, as on lap 6 (before Piastri’s overtake) he was 3.2 seconds behind Norris in P2, with an average of 0.5 seconds lost per lap.

Leews Hamilton post-quali at Monza, Ferrari, Italian GP

Lewis Hamilton

Interviewed by Sky Sports F1 at the end of the race, Leclerc himself described the issue as follows: “The first lap was really difficult. I struggled to get the tyres up to temperature. I was sliding a lot, and my rear tyres quickly overheated. At that point, I had no choice but to manage the overheating and try to get the tyres back up to the right temperature. The problem was that we lost a lot of time at that point.”

In conclusion, the race in Monza underlined how the SF-25 project has been a complete failure from all points of view and, as underlined by Hamilton in the post race interviews, “I don't think I have the right car to fight for the podium for the rest of the season”, proving that the team should now better focus on 2026, to avoid another disastrous season as the one they’re currently experiencing.