Welcome to The Briefing, where we’ll be answering the key on-track questions ahead of the São Paulo Grand Prix.

Each week, powered by Google Cloud, we’ll be speaking to one of our trackside experts to walk you through the biggest talking points and provide you with a simplified guide of what you’ll need to know to jump straight into the action. This week, ahead of FP1, we spoke to Tom Stallard.

Brazil’s unpredictable weather dominates a lot of the conversation in this weekend’s edition of The Briefing, with the forecast currently suggesting showers throughout, though the reality is that anything could happen.

The team had plenty to pack into the weekend’s sole practice session, with the Sprint format returning in São Paulo. Their work will have included testing the newly resurfaced sections of the track, preparing for the range of possible weather conditions, and assessing how the circuit’s short length will affect their plans. With Tom’s help, we’ll outline what these questions are and how we intend to answer them.

Before getting into the fine detail, let’s look at the weather forecast. Not great, is it?

No, not ideal! Sunday looks like it might be dry, and the forecast suggests Qualifying will also be potentially dry, but we’re definitely going to have some weather-affected sessions. The tricky thing will be managing a limited number of Intermediate tyres. You can get through those quite quickly in Qualifying sessions – and on a Sprint weekend, we’ve got a lot of Qualifying sessions.

The forecast is suggesting showers all weekend rather than solid rain. What are the big issues when the weather is unsettled?

Again, it comes down to the tyre allocation. The rules for Sprint Qualifying require you to use Medium, Medium, and Soft sets across SQ1, SQ2, and SQ3 – but if the track is declared wet, and then dries, you can use whatever compounds you like. The worst-case scenario is a little bit of rain before the start, in which the track is declared wet, but is still dry enough for slicks.

We have six sets of Soft tyres for the weekend. In this scenario, it would be very easy to use three in Sprint Quali, leaving you with only three more for Qualifying, which might also be dry. There are eight points available for the Sprint and 25 at stake on Sunday – so there’s a complicated decision to make. Certainly, you can’t just throw everything at Friday. That’s the problem – I’m honestly not sure what the solution would be!

The forecast shows a change in wind direction and cooler temperatures for Sunday. What impact will that have?

It can impact ride height. The wind changes direction, resulting in more grounding, which wears the skids more, and the car may potentially be disqualified for excessive wear. It’s one of those things every team needs to be on top of. Regarding temperatures, it’s a question for the aero guys to consider whether cooler temperatures mean we can close up the bodywork a little, and run with less cooling – but you need to have faith in the forecast.

The track has been resurfaced again this year. What does that do?

Interlagos was resurfaced before the 2024 race, but honestly, it wasn’t a great job! The two straights were very, very bumpy – more so than before the work, and so they’ve had another go, and resurfaced from Turn 12 (Junção) to Turn 1, and Turn 3 to Turn 4. Our expectation is that they’ll be more like they were in 2023 – certainly not worse than last year – but we’ll only find out when we’re out on track.

With just one practice session, there is very limited time to make setup changes. Do you have to estimate track condition?

Ultimately, you would rather be a bit too soft than too stiff when setting up the car, so we’ll err on the side of caution with that. Too soft and you give up a bit of performance, too stiff and the driver needs to wear a gum shield! That’s the approach from a setup point of view. 

The 2024 experiment with softer compounds has been rescinded, and we’re back to the allocation from 2022-23. Do you have some learning to do with the C2 Hard, given it wasn’t here last year?

Definitely some learning to do with the C2, because there’s a sizeable debate around whether the race is a one-stop using a Hard tyre, or if it’s a two-stop using Medium and Soft, or even if there’s potential for a one-stop with Medium and Soft - though that seems unlikely. Again, the caveat is the weather. Looking at the forecast, it might be a case of suck-it-and-see on Sunday!

What is the team thinking about the rear wing level?

Again, it’s a little bit dependent on what we see in the forecast. Last year, we ran a medium downforce rear wing for the Sprint, which was dry, and then, because we knew Qualifying would be wet and were pretty confident of a wet race also, we changed to a high downforce rear wing. It’s between those two again. The default is going to be medium downforce – because it’s the right choice for the dry. Whether we choose to add more downforce really depends on what we’re expecting later in the weekend.

For the second race in a row, we’re at a short track. What’s that like for you? 

Certainly, on Friday and Saturday, less time for analysis, and also more problems with traffic, with 20 cars squeezed into a very short lap. So, I’d say it’s more complicated, and that there is more work to do, in terms of finding a gap, getting the driver into clean air, not impeding other cars. You’ve also got less time on cool-down laps to get feedback from the driver and make a decision whether to pit or if he thinks he can improve.

On Sunday, it’s a bit of a mix, particularly in changeable conditions. If you go past the pit entry in somewhere like Spa, you can be very, very wrong, whereas here, that jeopardy is reduced, but equally, it changes the equation for pit stops, undercuts, things like that. It’s a busy weekend for everyone!

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