Why Mexico GP second practice is different from the rest of the F1 season

Formula 1 practice on non-sprint weekends is a familiar format – teams have an hour in both FP1 and FP2 on Friday and then a third 60-minute session on Saturday before qualifying.

But the second practice at the Mexico City Grand Prix will take on a different format as Pirelli conducts a crucial test ahead of its 2025 tire compound equivalence.

The change mirrors one made for last year's event, where the Italian manufacturer trialled a prototype C4 compound ahead of the current campaign.

Pirelli needs real work data when finalizing its equivalence ahead of the new season, which will again see F1 travel to 24 destinations around the world, and with a lack of in-season testing time, this weekend's practice session has been identified as an opportunity to gather information.

As explained by Pirelli, the session will be devoted to “fully validating” the softest compounds in the tire range for next year: the C4, C5 and C6 compounds.

To facilitate testing, FP2 will be extended to 90 minutes, with all drivers and teams obliged to follow a run plan established by Pirelli's engineers.

So, in addition to the usual dry tire allocation for the Grand Prix weekend, drivers will be given two more sets of tyres. One will be the test control tire – ie the same compound as the soft one in the normal allocation – and the other will be a 2025 prototype, which Pirelli confirmed was homologated in September.

Specific programs will include a qualifying simulation run and a race simulation run, where “each team is running the same amount of fuel over the same number of laps” – depending on which type of run is being performed.

These tire sets will be identifiable as they will not run with colored sidewalls.

A complication for the test is that some contracted race drivers will make way for rookies to complete one of the rule-mandated rookie runs in FP1, potentially removing those who are moved to a disadvantage due to a lack of on-track time compared to rivals. .

Pirelli countered this by handing the victims an extra set of medium compound tires for FP2 and allowing them a 30-minute 'free' run, thus forcing them to complete only 60 minutes of tire testing.

The test data will be analyzed ahead of the post-season group tire test, which will be held at the Yas Marina Circuit in Abu Dhabi.

With essentially just two hours of running to collect race-representative data, the teams will face similar engineering challenges as the sprint weekend, albeit with little respite from extra practice sessions before locking in at Park Farm.

Why did Pirelli choose Mexico?

While you'd expect the weekend to gain extra time for teams and drivers, it doesn't really work out that way for everyone given the testing requirements.

Haas driver Nico Hulkenberg's race engineer Gary Gannon told Motorsport.com that drivers should not be forced to change the balance of the car behind running on prototype tyres.

Gannon also pointed out that there is no advantage to running two contracted racers in FP1 who are driving over test rookies, explaining: “If you don't run a young driver in FP1 you can't use the extra time, so for us, two runs. Racing drivers in FP1, in FP2 we are only doing the Pirelli tire test programme.

“So FP2 is lost in terms of our understanding and usage for the race weekend, so we have to do all of our Friday learning in FP1.”

Autodromo Hermanos Rodriguez is an outlier on the F1 calendar due to its track layout and high altitude, which would suggest it as an odd choice for tire testing.

But that's exactly why it was chosen and Gannon added: “Pirelli's tires have to work in all conditions, so it's particularly important to find out if it's particularly weak… They might have a compound that works great in Barcelona, ​​the tires have a lot of power. And tires work because you're always pushing them.

“Here is an extreme case and so we have a good baseline, we have baseline tires and we have the morning race so they will understand how the grip should be. Also, the track improves a lot in FP1, so you will test in FP2, because If you try to test out of the box in FP1, the track is changing very dramatically as it clears and goes in.

“In FP2, the conditions are very stable, so you can find out if there's some weakness with this new compound or the new construction they've come up with, with very little grip or smooth tarmac surfaces.

“So they need to try all these outlier circuits because that's where you're going to have a miserable weekend if you supply tires that only work at low-low power.”