TYRE REPORT: Pirelli completes vital in-season test in Mexico

With teams having been required to follow Pirelli's run plan in the second practice at the Mexico City Grand Prix, the Milan-based tyre supplier insists that the unusual running has been vital for them to finalize their 2025 F1 tyres.

The F1 field completed a very different Friday to usual on the opening day at Mexico City’s Hermanos Rodriguez circuit. After the first free practice session was affected by red flags, the second one was planned to be entirely given over to what is known as an in-competition test, extended to 90 minutes to compare the current C4 and C5 compounds against prototypes of the same compound, as well as a new specification, the C6, which are to be used next season.

Reflecting on the unusual practice day at Mexico City, Formula One's sole tyre supplier Pirelli's chief engineer Simone Berra noted that it was "a very important session for us, with a packed programme: not only did we need to gather as much data as possible for the rest of the weekend, but above all, because the in-competition test was the final opportunity to finalise the compound choice, at least as far the softer compounds in the range are concerned, for the 2025 season.

"With 44 of the total 150 minutes that should have been available lost with the three interruptions, it definitely did not make life easy, neither for us, nor for the teams whom we must thank for their cooperation in running this test.

In the first session, all the drivers, including five rookies - Oliver Bearman (Ferrari), Kimi Antonelli (Mercedes), Patricio O’Ward (McLaren), Felipe Drugovich (Aston Martin) and Robert Shwartzman (Sauber) – started off on a set of the Hard compound before switching to Softs.

Although the five rookie drivers were intent on racking up mileages, there were two red flags: one to remove debris from the track, the other following a collision between Bearman and Alex Albon in the Williams, and these reduced track time by 20 minutes.

Having finished second at Austin last Sunday, Ferrari's Carlos Sainz was quickest in FP2, having set a time of 1m17.699s on a performance run with a C4 prototype. McLaren driver Oscar Piastri set the second-quickest lap with a time of 1m17.877s on a set of C5 prototypes, with RB's Yuki Tsunoda ending up third quickest, using a set of standard C5s.

For the final part of FP2, the five race drivers who had not run in the first session were able to run a set of Medium tyres in order to partially make up for the time lost in the first session. However, it should be noted that in FP2 all drivers were able to carry out at least two runs – one short and one long – with either the C4 or C5 that were available to them for this event.

Berra commented: “As for the Mexico City race weekend, there were few surprises compared to what we had expected. First and foremost, in the first session there was practically no graining. It’s true that there were not many very long runs, but on a track where in the past, graining played a significant role, that’s already a positive sign.

"The track seemed quick right from the start, with times significantly faster than last year’s, while running in very similar temperatures. The performance evolution was significant, along with, in FP2, quite a drop in temperature as dusk gradually approached.

“As for the in-competition test, clearly we gathered a lot of data, as it’s not often that we have 20 cars running in the same conditions with different options being compared at the same time. That will require an accurate analysis, but the very first indications have nevertheless emerged.

"First of all, we can say that the new compounds generally proved to be more mechanically resistant than the current ones, which should reduce the phenomenon of graining. Digging down further into the detail, we saw some rather promising and improved C4 options, both in terms of performance and degradation.

"As for the C5, there are solutions that seem to contain the degradation more, while of the C6s, there is one that seems clearly better, but we need to look at how to position it compared to the C5 in the 2025 range.”