The UBS Chinese Grand Prix was a thrilling race, despite the comfortable winning margin for Nico Rosberg in the Mercedes.
Race strategy was crucial to the outcome and we also learned a lot about how F1 has changed in 2012, with the field closing up on performance, so the top teams can no longer rely on building gaps over the midfield to drop nicely into after pit stops. The leading teams will have to work much harder than last year on creative race strategy and the drivers will have to do a lot more overtaking.
During Friday’s Free Practice 2 it was clear that many teams have yet to master the best set up on their cars for both qualifying and the race, going from high fuel to low fuel.
How Mercedes surprised with its race pace
McLaren appeared to have race pace that was 0.5s a lap faster than Mercedes, but overnight on Friday Ross Brawn’s team made some changes to the set up to improve the tyre life and at the end of the Saturday morning session Schumacher ran a handful of laps on high fuel to confirm the changes. This was not noticed by many in the paddock, but proved crucial to Mercedes’ victory.
The track temperature was foremost in the minds of the team strategists as they prepared for the race; these 2012 Pirelli tyres are very sensitive to temperature changes and in qualifying it was clear that a drop of a few degrees created a disparity between different cars.
The rough rule of thumb is; Mercedes likes the colder temperature, as does the Sauber, while the Red Bulls, Lotus and McLarens operate better in higher temperatures. This is a trend that is likely to continue all season, so in Bahrain the picture may look different from China.
As with last year’s Shanghai race, the key strategy decision was between two pit stops and three and the timing of them. Pre race predictions showed that two stops was faster than three by up to 7 seconds, but the danger was that the two stopping driver would be vulnerable in the last five laps on worn tyres.
Crucially, the decision on which strategy was faster varied from team to team, depending on how fast they could run on the medium tyre. McLaren, for example, found it slower than the soft, while other teams including Mercedes, Lotus and Williams thought differently.
Rosberg vs Button vs Hamilton
McLaren went for three stops, Mercedes for two; the pattern was set. One of the reasons why Hamilton in particular was obliged to do three stops was because in qualifying he set his fastest time on a set of tyres that had done six laps by the time he started the race. This meant he would struggle to make it to lap 13, which was the window for two stops.
Mercedes knew this and planned to exploit it. Rosberg and Schumacher were instructed to get to at least lap 13, at which point they would switch to a medium tyre and do a middle stint of 21 laps, then a final stint on mediums again. Button was the greater threat to them on his three stop strategy, based on two stints on the soft tyre, but his challenge faded with a botched final pit stop, where the left rear wheel change was delayed by six seconds.
So when he rejoined, instead of being 14 seconds behind Rosberg with 17 laps to go and tyres that were 5 laps newer, he was 20 seconds behind.
The pit stop problem – not the first McLaren have suffered at critical moments this season – had a further knock-on effect in that it brought Button back out into the train of cars led by Massa and Raikkonen, who were two-stopping. Instead of gaining on Rosberg, Button could not take advantage of his new tyres, lost a second per lap to him and the race was over.
Most of Hamilton’s race was spent in traffic as well, due to starting down in seventh place after his gearbox change penalty. He could never get clear of the competitive midfield cars and run in clear air, so progress through the field was difficult on the three stop strategy he was obliged to do. A strategy like that requires plenty of opportunity to drive flat out on a clear track.
Another factor that worked against McLaren was that they had to cover Mark Webber, who made extremely early stops. So this caused them to pit earlier than intended and meant that they didn’t have the fresh tyre advantage over Rosberg and the two stoppers they wanted and needed to cut through the field.
Intense competition in midfield
Quite a few cars in the midfield tried the two stop approach, based on two stints on the medium tyre, with mixed results; the key here was being able to extend the middle stint so as not to leave yourself too many laps at the end on the final set of tyres.
Vettel went for it, to try to get himself up from his lowly 11th grid slot, as did Massa from 12th, Senna from 14th and the two Lotus drivers. Raikkonen started 4th and Grosjean 10th.
It is interesting to compare the results these drivers achieved, all trying to do the same thing. The most stark example of it going wrong is Raikkonen – he fell from 2nd place, with just nine laps to go, to 14th at the finish! Partly this was due to worn tyres after a 28 lap final stint, but he also got off line trying too hard to defend his position from Vettel. His tyres got dirty and this allowed other cars to pass him. He got in a vicious circle; as he defended against them the tyres got dirtier still and all hope was lost.
The reason he found himself in this position was because he pitted too early for his second stop on lap 26. His middle stint was only 16 laps long on the medium tyre so he blinked too early on coming in for the second stop.
Conversely, Senna started on the medium tyre, did a middle stint on his new set of soft tyres, pitted for the second time on lap 29 back to the medium and managed to gain places when the three stoppers made their final stop. Senna’s drive showed how well balanced and competitive the Williams car is this year. He managed to get an 7th place finish. Vettel went from 11th to 5th at the finish, making the most of the strategy by pulling off a long middle stint on medium tyres.
Grosjean drove well, to collect his first points of the season, but it could have been better. He managed to go four laps longer than team mate Raikkonen in the middle stint and this set him up for a great result in 5th place. He was sitting there with 12 laps to go, but made a mistake when fighting Webber and lost three places. He managed to get two of them back, which shows that he still had life left in his tyres, despite them being only three laps fresher than Raikkonen’s.
The UBS Race Strategy Report is written by James Allen with input and data from several F1 team strategists.
RACE HISTORY GRAPH
The Y axis is the time behind the average laptime line. So, for example, when Rosberg’s curve is going down and away from the zero line it means that he’s doing laptimes slower than the average, and when his curve is going up and towards the zero line it means he’s doing laptimes faster than the average. The coloured lines show the pace of other cars relative to the leader.