Feature F1 Unlocked
STRATEGY UNPACKED: Was starting on the hard tyre the key to Verstappen’s victory in Miami?
A theme emerged during the Miami Grand Prix as several drivers made up plenty of ground after starting the race on the hard-compound tyre. But why was this approach so effective for so many? Ex-Aston Martin strategist Bernie Collins runs through the data.
Sunday’s Miami Grand Prix saw Max Verstappen snatch victory from ninth on the grid. The Dutchman started on the hard tyre and a long first stint allowed 25 laps in free air to maximise car pace and secure the win.
However, the strategy was not unique to Verstappen nor Red Bull. Arguably Verstappen had the pace to win regardless of the strategy selected (more on that below). So what of the others?
Seven teams – Red Bull, Mercedes, Alpine, Aston Martin, Haas, Alfa Romeo and AlphaTauri – chose to split the start tyre across cars between the medium and hard. All of these teams put the driver that started further back on the grid on the hard start tyre, and the driver ahead on the medium.
This indicates that they all expected the medium start tyre strategy to be preferred, and that the hard tyre brought benefits to the drivers starting further back and out of position.
During the Friday long runs, tyre graining proved to be a significant issue on the medium and soft compounds. The new resurfaced tarmac provided faster lap times. The pole time this year was almost two seconds quicker than last year, although around one second of this improvement comes from the re-profiled Turn 15 section.
What is tyre graining?
Graining is an issue caused when the tyre experiences an extreme surface temperature outside the desired operating condition. In this case, hot track temperatures and quicker lap times result in the tyre surface easily becoming too hot.
Low track grip as seen in the Friday sessions or Sunday at the beginning of the race (post-overnight rain) allows further sliding of the tyre and again increases surface temperature and therefore graining risk. The softer the tyre compound, the greater the risk of graining.
Graining distorts the tyre surface and it begins to lose performance compared to a tyre that has not experienced graining. Graining can be managed by controlling the surface temperature through driving style and slower lap times.
The heavy fuel load at the beginning of the race would also be a factor as more is demanded from the tyre in terms of load but often this is traded against faster lap times at the end of the race on lighter fuel. Graining can often clear up as the tyre surface wears away, revealing fresh rubber underneath.
All teams were expected to and did have to manage graining during the race. Sergio Perez was initially told to look after the front right until temperatures had stabilised and then later commented that the graining was clearing up a bit.
In the second stint on mediums, Verstappen was told that wear wasn’t an issue – he just had to be aware of the offset of any graining. This indicates that graining was a potential issue across both stints.
Throughout the race on Sunday, the track temperature was relatively stable and lower compared to some earlier sessions due to cloud cover. This would have helped reduce the risk of graining. However, in the opening laps of the race the lap times improved significantly as the track was cleaned from overnight rain by the cars lapping.
The first 15 minutes show strong improvement in lap time and then the lap time is reasonably stable when corrected for fuel and tyre degradation effects. These first 15 minutes were probably the hardest to control graining while also fighting for track position.
Why start the race on the hard tyre?
So, why start on the hard tyre if graining on the medium was an issue for both the first and second stints on this tyre?
Let’s first look at the risks. Launch from the grid will obviously be worse on the hard tyre. Miami has the fifth-shortest distance of all circuits from the grid to T1, which means any difference in launch due to initial grip was minimised.
The biggest risk therefore is a Safety Car at any point before it is possible to stop from a hard start tyre and make it to the end of the race on a medium tyre.
The greatest advantage of a hard start tyre for the majority of the field – especially for drivers who have started out of position – is the ability to find some free air when not in traffic to use car pace to its maximum potential.
With medium runners expected to pit between Lap 13 to 20 then, this was the opportunity for cars out of position that had started on hard tyres to push and over-cut slower cars.
How did strategy pan out for the hard starters?
The trace above focuses on five teams that split strategies across start tyres; Red Bull, Aston Martin, Mercedes, Alpine and Haas. It shows the strategy completed by each driver. The chart would show a flat horizontal line if a driver completed the same lap time every lap.
Moving upwards shows a lap faster than this average lap and the sharp fall downwards represents a pit stop. The circle at the pit stop shows the tyre that was fitted. The order on the right-hand side from top to bottom shows finishing position. The same average lap time is used for all, so slower drivers appear lower down on the chart.
Aside from Verstappen, none of those that started on the hard managed to beat a team mate who started ahead on medium. Although all those that started on hard gained more positions than team mates that started medium this is in general as they had more positions to gain due to starting further back rather than stronger strategy.
Those furthest back on the grid, such as Lewis Hamilton and Lance Stroll, would have been hoping that fewer cars ahead started hard in order to find even more free air.
Hard vs medium starting tyre
|Hard tyre starter||Position change||Medium tyre starter||Position change|
|Verstappen: P9||+8||Perez: P1||-1|
|Hamilton: P13||+7||Russell: P6||+2|
|Stroll: P18||+6||Alonso: P2||-1|
|Ocon: P8||-1||Gasly: P5||-3|
|Hulkenberg: P12||-3||Magnussen: P4||-6|
The table above summarises the starting positions and positions gained by the end of the race for the five teams compared.
Verstappen, being the leading car on the hard tyre in the first stint, found the most free air relative to others and, combined with superior car pace, gained the most. Further back in the grid, the difference in starting on the medium or the hard tyre was relatively small at the end of the race.