Despite Pirelli indicating that the two-stop strategy was the clear way to go at yesterday's United States Grand Prix, four drivers attempted to perform a single-stop strategy, but neither of them succeeded. F1Technical's senior writer Balázs Szabó takes a look at the strategies used in the Austin F1 round.
For the demanding Circuit of the American, Formula One’s sole tyre supplier Pirelli brought three compounds from the middle of its 2023 tyre range: the C2 served as P Zero White hard, C3 as P Zero Yellow medium and C4 as P Zero Red soft in Texas.
The tyre selection was motivated by the high-speed nature of the track. Some corners on the Herman Tilke-designed Circuit of the Americas are inspired by famous turns at other renowned tracks. Turns 3 to 6 are reminiscent of the Maggotts-Becketts complex at Silverstone, turns 12 to 15 are inspired by a section of the Hockenheimring, while turns 16 to 18 take after the celebrated turn 8 at Istanbul Park.
The aforementioned combinations of corners in the first and third sectors are taken at extremely high speeds which means that tyres are subjected to unusually high lateral loads for a relatively long period of time.
As it was the case last year, Pirelli predicted that the two-stop strategy would turn out to be the quickest way to complete the 56-lap Austin F1 round.Crucial strategy decisions
The vast majority of drivers preferred to start on the Medium tyres, the only exceptions being Lance Stroll and Nico Hulkenberg, who started on Hard from pit lane alongside their respective team-mates Fernando Alonso and Kevin Magnussen.
Although degradation was not exceptionally high, it was clear that the majority of the field planned a two-stop strategy. However, there were four drivers who attempted a single stop strategy. The Mercedes duo of Lewis Hamilton and George Russell extended their first stint until Lap 20 and 21 as their team believed that the one-stop strategy might be the quicker approach.
When the mediums on Hamilton’s and Russell’s car started to show a greater than anticipated degradation on Lap 19, Mercedes abandoned the idea and converted the strategy to a two-stop approach. Although both Hamilton and Russell lost a significant amount of time after their rivals rejoined the track on fresh tyres, Mercedes thought that the offset strategy would pay off later on in the race.
There were, however, two drivers who pursued the one-stop strategy. Charles Leclerc extended his first stint to lap 23 before running the remaining 33 laps on a set of Hards, and Daniel Ricciardo who first stopped on Lap 22.
While Leclerc’s tyre management was better than anticipated, his last two laps of his opening stint were almost two seconds slower than what his direct rivals managed on fresh tyres. Even if the offset could have provided some benefits, it was such a disadvantage that Lando Norris closed in on Leclerc until the Moneagsque decided to pit for new hards on Lap 23.
Commenting on Ferrari’s less than ideal strategy, Team Principal Fred Vasseur said: “The main problem today was with Charles’ strategy, decided on before the start, but which did not work out and therefore compromised his race. Our data suggested that there was not a particularly big difference between a one and a two-stop strategy, but events proved us wrong.”
In reality, Ferrari could have switched to a two-stop strategy with Leclerc, but they left the five-time grand prix winner on the track instead until he lost positions to his team-mate Carlos Sainz and Sergio Perez in the closing stages of the race.
Had Leclerc committed to a late pit stop, he could have still rejoined the track in P6, the position in which he ended the race. Doing so, he would have had the chance to close in on the Spaniard and the Mexican and attack them in the dying stages of the race.
The other driver who was eager to complete the United States Grand Prix with a single stop, Daniel Ricciardo, aborted his attempt to get to the chequered flag on the Hards, switching to Softs for the final eight laps.
His AlphaTauri team-mate, Yuki Tsunoda did the same, making a third stop on the penultimate lap, attempting and succeeding in taking the additional point on offer for setting the fastest race lap as he rounded off the top ten.
Another lesson for the teams to learn was that the medium compound was clearly the most effective race tyre yesterday. It meant that the best approach was to complete two stints on the yellow-banded tyre and another stint on the white-walled hards. Teams were aware of this, that is why most of the outfits - except McLaren - completed the sole practice on Friday with the hard and soft compound to save three sets of mediums for the sprint race and the grand pix.
Moreover, the best permutation was to start the race on the medium to have high grip off the line before completing the middle part of the race on the hards. The lower fuel load and the grippier track meant that the best compound to complete the race distance was the medium compound.
Considering the strategies, it is no surprise that Chalres Leclerc completed the longest stint on the Hard compound with a 33-lap stint. The quickest lap on this compound was posted by Sergio Perez, who clocked in a 1m39.737s on Lap 40 three laps into his last stint.
Alexander Albon performed the longest distance on the medium tyres with a 27-lap stint. The best time on this compound was posted by George Russell who registered a time of 1m39.393s on Lap 48 nine laps into his last stint.
Yuki Tsunoda posted the fastest race lap that saw him earn the bonus point. The Japanese had a ‘free’ pit stop ahead of Alex Albon which motivated his team to call him in for new soft tyres that allowed the AlphaTauri racer to post a 1m38.139s on the ultimate lap of the 56-lap United States Grand Prix.
Speaking of the 75th F1 race staged in the United States, Pirelli's Motorsport Director Mario Isola said: “On one of the most probing tracks of the season, we witnessed a very closely contested race, with exciting duels both on track and between the strategists.
"On the topic of strategy, the way the race played out confirmed that a two-stop was the quickest option, especially because the one-stop alternative would require very careful tyre management thus making it difficult for a driver to push hard for many laps, while those on two stops were able to do so. That was the case with Leclerc who, although he did not see a drop in performance towards the end due to degradation, found his pace was not strong enough to defend from several drivers who chose to pit twice.
"Looking at tyre performance in general, the Medium proved to be the most suitable compound, because it offered more grip than the Hard, but its degradation did not result in much slower lap times. The Soft was hardly used – only by AlphaTauri in the closing stages – and looking at Tsunoda’s performance it showed it was a great tyre over a single flying lap, but not really an option over a long distance on this Austin track with today’s temperatures. Finally, it’s worth noting that even in the race there was no graining," concluded Isola.