Welcome to The Briefing, where you can get a jumpstart on the Mexico City Grand Prix with our guide to the key topics.

Every race weekend, we’ll speak to one of our engineers to discuss the key talking points ahead of the upcoming Grand Prix and simplify them so that you can dive straight into the action with a better idea of what to expect and what you should be looking out for.  

This week, powered by Google Cloud, Jose Manuel López has joined us to talk through a busy few practice sessions and what they mean for the weekend as a whole. Pato O’Ward will replace Lando for Free Practice 1, and he’s been given a lengthy to-do list. Jose will also explain Pirelli’s in-session tyre test and walk us through the many unique elements of Mexico City’s Autódromo Hermanos Rodríguez, which include the impacts of its high altitude on downforce and cooling.

Here’s what we’ll be working on and what you need to know…

1. Pato's got plenty to work through in FP1

We have a very busy but also very unusual Friday programme for the Autódromo Hermanos Rodríguez. The first thing to note is that Pato O’Ward will be subbing for Lando in FP1. He’ll be getting up to speed but also conducting some experiments.

We are bringing a few new parts with us, which Oscar and Pato will be testing and comparing throughout the session. Oscar will run the old parts and Pato will back-to-back run the new and the old, to confirm they’re working as expected. Doing it this way gives us both a car-to-car comparison and a same-car comparison, which should give us some robust data.

Pato’s done plenty of preparation for this, in the sim and also on track in Driver Development tests. He’ll be doing quite a few CSL [Constant Speed Limit] runs on the straights. We’ll pre-prepare the floor to make the changeover as slick as possible, but it will still take about 20-25 minutes to make the change, so Pato will have some downtime in the middle of the session.

2. FP2 will include an in-session Pirelli tyre test

Lando will be back in the car for FP2, but this will also be a strange session as we will be doing an in-session Pirelli tyre test. Every team will be operating a programme set-out by Pirelli, who will provide unmarked tyres from both the current and 2025 range. To accommodate for this, the session will be extended to 90 minutes instead of the usual 60 minutes.

Because Lando won’t run in FP1, he (and any other drivers that don’t take part in FP1) will be allowed to use an additional set of Medium tyres in the last 30 minutes of the session to catch up on their race preparation.

3. The Autódromo Hermanos is a unique circuit

Those are the unusual elements of the programme. We also have the more standard race preparation work to do – but the Autódromo Hermanos Rodríguez is, in itself, an unusual circuit. We’re racing this week above 2,000m, which means air density is very low, which in turn means that the downforce we can generate is also extremely low, even running a high downforce package on the car.

The consequence is that the drivers will feel like the grip is very poor, it will be very easy to lock a tyre and difficult to put a lap together. We’ll try to help the drivers by giving them a car that is a little more forgiving.

4. Selecting the right set-up and choosing the right tyres

Regarding tyre choices, in the past, the track has been in between one and two stops. If the grip is a little higher than expected, that would nudge you towards a one-stop, if it's a little lower, then two stops. We’ll be investigating this – but either way, this is a circuit where you have to look after the tyres very carefully, and lock-ups can really ruin your race. So, we will be doing a lot of work to limit this.

In terms of the aerodynamic set-up, we’ll be running a high downforce rear wing, but there are a couple of options we have available that we’ll try on Friday. We haven’t settled on which one we want to run yet. We’ll evaluate both and look at what our competitors are doing before coming to a final decision.

The back straight and the stadium section have been resurfaced, so we’ll want to evaluate how that has affected the level of grip. But we also know the bits that haven’t been resurfaced are very bumpy, which also contributes to locking tyres. And there are a lot of kerbs that the car will have to ride. Again, with the low downforce, that can contribute to three-wheeling and hopping. It’s a constant challenge for the race engineers and drivers to decide how much can be tolerated and then adopt an appropriate set-up.

It will be a real challenge for the team to find the right levels of stiffness. There are a lot of corner combinations to get through that need a car that copes with a sharp change of direction but equally one that can get over those kerbs in as straight a line as possible. There are some complex trades to make this weekend.

5. Cooling the car can be tough in Mexico City

The altitude also makes cooling the car challenging - simply because the thin air doesn't provide the same level of cooling as what we get down at sea level. You will therefore see teams running with very loose bodywork around the engine, bigger scoops to cool the brakes, and more louvres for PU cooling. Some years, we're more concerned about the brakes, and others, we're more concerned about the PU. Realistically, we're always concerned about both.

The challenge isn’t so much about cooling the car in isolation, but ensuring it can cope when running behind other cars, when the airflow is interrupted. Across practice we’d like to see how the car responds both when running on its own, but also when it is in traffic.

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