Pirelli Report: United States Grand Prix

Lewis Hamilton has won the United States Grand Prix and the 2015 World Championship, following an action-packed race that went from wet to dry conditions. All the drivers started on new intermediates, waiting for the right crossover point when the track would be dry enough to move onto slicks.

Both Hamilton and his team mate Nico Rosberg, who finished second, completed one opening stint on the intermediates followed by two stints on the soft tire.

The timing of the pit stops proved to be the key to victory, with the pit wall and drivers having to make tactical calls despite no dry running before the start, which deprived the teams of the usual tire wear and degradation information.

Two safety cars (as well as two virtual safety cars) shaped the strategy, with Hamilton stopping during the second safety car period – just before the finish – but not during the first safety car period, earlier in the race.

Those who stopped during the first safety car period looked like they had an advantage, but the second safety car period eliminated a large part of that, by allowing those who hadn’t yet stopped to do so while containing the pit lane time loss. Hamilton emerged from his second and final pit stop in second place, but used the speed advantage of his fresh P Zero Yellow soft tires to claim the lead from Rosberg, who had started from pole following the qualifying session this morning.

The highest-placed three-stopper was Ferrari’s Sebastian Vettel, who ended up on the podium. Vettel made his second stop onto the medium tires, rather than the soft tire used by his direct rivals. However, he then made a third stop during the final safety car, at the same time as Hamilton, having started from 13th on the grid. With the race start held in wet conditions, there wasn’t the usual obligation to run both slick compounds. Most drivers chose to use the faster soft tire throughout the dry part of the race, but Vettel was the first of the frontrunners to use the more durable medium.

Force India’s Sergio Perez was the only driver to make the intermediate-soft-medium strategy work, finishing fifth after stopping twice. The Mexican finished ahead of McLaren’s Jenson Button and Toro Rosso driver Carlos Sainz, who went from last following an off in qualifying to sixth at the race finish: also stopping three times. The highest number of pit stops was completed by Sauber’s Felipe Nasr, who was in the pits five times but still finished in a points-scoring ninth.

Paul Hembery, Pirelli motorsport director: “After several delays and washouts, we finally got the race we had been waiting for, where the wet conditions at the start added another fascinating tactical variable rather than just being an impediment to the action. As was inevitable with no dry running before the start, the teams had to read and react to the changing situation rather than rely on prior information, so it was the drivers who were able to work with their teams best under these challenging circumstances who won out. Congratulations to Lewis for a well earned third championship title, after a brilliant season. Right to the end, the final outcome of this grand prix was unclear, ensuring a thrilling finale to the race that the fans deserved most of all, after a weekend that is certainly going to be very memorable…”