Before the race started, teams were certain that this would be a one-stop race. The Pirelli tyre choice of Medium and hard was quite conservative and there were no signs of the extreme degradation that had been such a feature of the first half of the season. Degradation was 0.02 sec per lap for the medium and 0.01 sec per lap for the Hard.
Pirelli had been influenced by the high temperatures in the November 18 week last year and for most of this year the temperatures have been 5 degrees warmer than seasonal average. So everyone expected it to be hotter than it was.
So the tyres would take time to warm up in the cool ambient conditions. But drivers were able to push to the limits for all 56 laps without needing to nurse the tyres.
However Austin proved to be a unique circuit on the current F1 calendar, by far the most difficult to align the temperatures of the front and rear tyres. Even with all the knowledge the teams had developed over the season, they were all scratching their heads about getting the tyre temperatures balanced front to rear.
On the first day of practice in Austin the grip level had been very low, due to the recently laid tarmac having a sheen of bitumen on the surface. This began to be ripped away, revealing the grippy stones underneath, but only on the racing line. As the weekend wore on and more rubber went down the grip level came up, giving a 10% improvement compared to Friday.
The biggest concern was what this would mean at the start, with the dirty side of the grid estimated to be one second slower reaching Turn 1 than the clean side. There were estimates of two positions lost at the start for cars on the dirty side. As a result, Ferrari opted to deliberately penalise Felipe Massa, starting 6th on the grid, by giving him a five-place gearbox penalty, which allowed team mate Alonso, who had underperformed in qualifying, to start 7th on the clean side of the track. It was a strategic decision and it worked very effectively, as Alonso made up three places at the start, giving him the platform for a podium finish, despite the poor qualifying pace of the Ferrari.
All the front running teams identified backmarkers as a potential problem in the Esses before the long straight – lose time through there and you would be vulnerable to a DRS overtake on the straight.
Lewis Hamilton and Sebastian Vettel fought a great duel for the victory in Austin and there were fine differences between the two cars’ performance on the tyres. The Red Bull was able to bring the tyres in more quickly and as a consequence Vettel did six laps on his tyres of which only two were at pace down laps. However Hamilton did seven, with three hard laps.
Although they lost the battle for pole position, on race day the McLaren had a slight pace advantage over the Red Bull. Both cars were strong on the medium tyre, Hamilton able to bridge a 2.5 second gap once he got clear of Mark Webber to close up to Vettel. But then his slightly older tyres reached the point where the performance dropped off. He lost almost two seconds in the three laps before his stop on lap 20. When he exited the pits he was behind Raikkonen and spent four laps behind the Lotus.
Vettel pitted a lap later, to cover Hamilton and re-emerged in the lead. However it soon became clear that the pattern we have seen recently of the McLaren being stronger on the harder prime tyre was being born out again. Hamilton was primed to strike as they reached half distance in the race. Although the McLaren had a pace advantage, Hamilton was not able to get close enough to Vettel in the DRS detection zone at Turn 11 to challenge using the DRS on the straight. On lap 42 he took advantage of Vettel encountering the back-marker HRT of Narain Karthikeyan in the Esses to close up and make his move on the straight.
Because of Red Bull’s tactic of setting the car up for down force, rather than straight-line speed, the McLaren had an 11km/h speed advantage over the Red Bull for this race and with the extra 10km/h from the DRS effect, Hamilton was able to pass. Although Vettel came back at him, the straight-line speed deficit meant that he couldn’t get close enough.
Jenson Button was forced to start the race from 12th place on the grid after a throttle failure in qualifying. This gave him the right to choose what tyre to start on and to use new tyres. Many team strategists felt that starting on the hard would not be competitive but Button was able to use the pace advantage of the McLaren to good effect. The strategy was to run a longer first stint and use the more sustained performance of the hard tyre to gain track position when the cars ahead made their stops after lap 20.
He lost around six seconds sitting in a train behind Di Resta, Perez and Senna in the run up to their stops, but once clear of them he had very good pace on the hard tyre and managed to get faster every lap until his stop on lap 35. McLaren were monitoring the gap to Grosjean in the Lotus and when they saw on lap 34 that Grosjean was faster than Button they pitted him, despite the fact that Button’s pace was still improving. This brought him out close to the Frenchman, but he fell behind. He was able to exploit the extra grip on the softer tyres to make overtakes under braking, such as the pass on Grosjean and was quick once he passed the two Lotus cars, but wasn’t going to catch Massa for fourth.
Interestingly Fernando Alonso seemed to struggle getting the hard tyres warmed up and Ferrari technical director Pat Fry admitted after the race that the car had not had the pace of its rivals on that tyre. As this same tyre combination is set to be used again in Sao Paolo, this is a concern for Ferrari, if the race is held in the dry. At the moment the forecast calls for a 60% chance of rain on Saturday and Sunday. However Felipe Massa seemed to have fewer problems on the hard tyre so there will be something to be learned from his data.
TYRE STRATEGIES, Austin
Hamilton: MU HN (20) 1 stop
Vettel: MU HN (21) 1
Alonso: MU HU (20) 1
Massa: MU HU (26) 1
Button: HN MN (35) 1
Räikkönen: MU HU (24) 1
Grosjean: MU HN (9) 1
Hülkenberg: MU HN (17) 1
Maldonado: MU HN (21) 1
Senna: MN HN (20) 1
Perez: MN HN (22) 1
Ricciardo: MN HN (30) 1
Rosberg: HN MN (34) 1
Kobayashi: MN HN (13) 1
Di Resta: MN HN (21) HN (31) 2
Schumacher: MU HN (14) HN (39) 2
Petrov: MN HN (23) 1
Kovalainen: MN HN (21) 1
Glock: MN HN (21) 1
Pic: MN HN (26) 1
De La Rosa: MN HN (24) 1
Karthikeyan: MN HN (25) 1
RACE HISTORY GRAPH, Kindly supplied by Williams F1 Team
Note the relative pace of Massa and Alonso on the hard tyre in the second stint, note also Button’s pace at the end of the first stint, still improving on the hard tyre after 34 laps.