F1 expert explains how teams decide when to RISK slick tyres in rain

Regen op Silverstone — Photo: © LAT Images

British Grand Prix

F1 expert explains how teams decide when to RISK slick tyres in rain

Teams have been faced with a decision at Silverstone this weekend

Shubham Sangodkar

Saturday 8 July 2023 16:07

The British GP at Silverstone is experiencing the typical unexpected British weather. Friday's practice sessions were clear and dry, while Saturday’s qualifying and Sunday’s race are expected to be a combination of dry and damp conditions.

In such situations, it's extremely important to understand what strategists refer to as 'crossover' points, i.e. when the best time is to jump onto an intermediate tyre in damp conditions and when the best time is to jump onto a dry tyre in drying conditions.

This is determined by what strategists refer to as 'cutoff times'. Let us look at the data to understand the cutoff times and their impact on qualifying and the race, with a focus on Silverstone.

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Crossover Points

Before the rain hit the track, Max was doing his usual race sim on mediums timing between 93 - 95 seconds per lap, which is the expected range of race pace around Silverstone on dry tyres.

When the rain first hit FP3, Leclerc stayed out to test the conditions with his warm soft tyres to understand where the cross-over times were, as can be seen in the plots below. As can be expected he was lapping inconsistently, as he was finding the grip and the limit on the damp track with dry tyres, lapping between 95 - 120 seconds per lap.

When they all put the intermediate tyres to test the conditions, both Leclerc and Verstappen were lapping in the 98 - 102 second range.

So where is the sweet spot then? Well from the data, the crossover point seems to be between 94 - 97 seconds.

What does this mean for qualifying?

Teams will be on the lookout for times in multiple sectors to understand how the track is evolving. Qualifying is expected to start off damp, which means getting the cutoff time for qualifying correctly is absolutely essential.

I expect Q1 to get very busy in the pits, as teams will try to put on a time to cover themselves for any red flags and then come in for dry tyres to set the faster lap later in the session, in case it keeps on drying.

What does this mean for the race?

In case there are mixed conditions during the race, teams will monitor the pace and whenever the times are in the transition region, they will brainstorm and decide what is the correct time to change tyres based on their position relative to their competitors.

Shubham Sangodkar is a former F1 Aerodynamicist with a Master's in Racing Car Design specialising in F1 Aerodynamics and F1 Data Analysis. He also posts aerodynamics content on his YouTube channel, which can be found here.