So much happened in the Chinese Grand Prix, it’s important to take the time to examine exactly how and why things worked out as they did.
The overriding observation is that strategy was the difference between winning and losing on Sunday.
While we have seen some interesting mixtures of strategy in the first two races, the podium finishers in both Melbourne and Sepang all did the same strategy. The Chinese Grand Prix was the first race to show variations on this and to illustrate how finely balanced some of the decision making is in F1 this year.
Another interesting difference from the first two races is that we had four fast cars out of their normal position on the grid; Webber 18th, Heidfeld 16th, Schumacher 14th and Petrov. This meant that the two Toro Rosso cars and the two Force Indias were in and around the top ten, but staying there proved difficult as the overtaking aids and the Pirelli tyres gave the faster cars the chance of come through the field.
The strategic thinking started in qualifying, where Lewis Hamilton decided to do only one run in Q3, saving a set of new soft tyres for the race. What exactly did this give him? In comparison to a set which has been used in qualifying, a new set will give an first lap performance boost, then it will last two to three laps longer than a used set, which have done that much already. On top of that the degradation on a used set means that every lap in the stint will be about 1/10th to 2/10ths of a second slower than the new set through the stint. And finally there is another benefit, which is that you delay taking the hard tyre an extra couple of laps and that tyre is around a second a lap slower. So it adds up to quite a gain.
Computer simulations showed that two stops would be faster than three by around 3 seconds over the race, but this was reliant on running in clear air. Vettel went with a two stop plan, but found himself behind the McLarens after a poor start. His KERS wasn’t working properly at the start. It only gave him 30bhp instead of 80bhp, which is why the McLarens got the jump on him.
At this point Red Bull had the chance to do three stops. But as he pitted only lap 14, the same time as Button and a lap before Hamilton and came out ahead of both, they decided to stick with two stops. They no doubt thought that their car was fast enough to make the strategy work. Had they followed a three stop plan from lap 14 onwards he would have won the race.
But what none of the simulations predicted prior to the start was how little the tyre life would improve during the race. Previous experience with Pirelli in the first two races had shown that the tyre wear is 25% better in the final stages of the race, compared to Friday Free Practice, when most teams do their long runs of 18-20 laps. But crucially, this time the circuit did not rubber-in, which meant the surface didn’t come to the hard tyre for the final stint, as is normally the case. This is why Vettel and all the other two stoppers, like Ferrari, couldn’t keep the pace up and Vettel got caught in the final laps by Hamilton, whose tyres were seven laps fresher. It is also the reason why Webber’s strategy worked out so spectacularly, as we will see.
Lewis Hamilton won the race, by getting the strategy exactly right. Saving a set of new tyres played its part in making the three stop plan work, as did making crucial overtakes such as the ones on Button, Massa and Rosberg.
This is true and we may see some of the faster cars doing what Hamilton did and limiting themselves to using just two sets of soft tyres in qualifying, because the benefit in the race is so significant.
Webber ran the three stop race strategy, but in reverse, starting on the hard tyre and them using three new sets of soft tyres, which he had saved by not doing Qualifying 2 and Qualifying 3. Webber was the only driver on the grid not to start on softs.
The three stop plan gave him plenty of free air to run in and at the end he was running on new soft tyres when all the other drivers were discovering that the track wasn’t improving and that the degradation on the hard was therefore worse than expected. New soft tyres gave him a huge pace advantage as proved by his fastest lap, which was 1.4s faster than anyone else!
Webber did exactly the right thing by running the prime early on, while stuck in traffic and unable to exploit the pace of his car. Had he started on options, he would have had to use the hard tyre at the end of the race and it would have been much harder for him to make progress.
Rosberg was fourth on the opening lap, then thanks to a great piece of of strategic thinking by Mercedes early in the race, they brought him in on lap 12 just as he was about to hit traffic. This brought him out in clear air. He was able to run unimpeded at this stage of the race and he was in the lead by lap 17, doing impressive lap times on his second set of soft tyres. After his second stop he came out in front of both McLarens and he must have thought he was on for a podium.
The Mercedes team thought they were going to win the race at this point.
But then it became clear that they didn’t have enough fuel to complete the race at competitive speeds and so he had to save fuel and the race got away from him.
In fairness to Mercedes this is an incredibly hard thing to predict. All sorts of things can upset predictions, like atmospheric pressure, track conditions, tyre conditions, meaning you use more fuel than expected. Rosberg’s Mercedes was much faster in race trim in China than it had been in Malaysia and this used more fuel. In Malaysia they had to open the bodywork up to keep it cool, whereas in China they could run the car in its optimal aerodynamic configuration.
All teams run at a fuel deficit at some points in the race, aiming to save fuel in the final stint. Mercedes clearly fuelled the car expected a lonely race in fourth place, keeping the Ferraris at bay, but the chance arose there to do something much better and they couldn’t take it, for want of a few more kilos of fuel in the car.
Ferrari: Wrong strategy
After the race, Fernando Alonso said, “You need to keep focussed on your own strategy. And in the end when you have a quick car, any strategy is good, as Webber showed today. When you have a slow car, everything is more difficult.”
Ferrari made the same mistake as Vettel in running a two stop plan, which was a shame because Felipe Massa looked the most competitive he has for a long time and on a three stopper could have been on the podium.
Both Ferraris were held up by Rosberg in the first stint. The drivers probably thought they could run quicker in clear air, so they stayed out when Rosberg pitted on lap 12. Massa briefly gained a place on Hamilton, but he and Alonso got split up.
Alonso had been behind his team mate after losing the start to him. He stayed out one lap longer than Massa at the first pitstop and that allowed Massa to stay ahead. Alonso then came out behind Schumacher and he lost a lot of time. It was somewhat surprising that Ferrari stuck so doggedly to two stops with both cars, you would normally split strategies in that situation.
It’s worth remembering that the difference in lap time between old and new rubber, when combined with the fuel load always getting lighter, means it’s no longer an advantage to run longer than someone prior to pitting. If the first person to stop does a strong out-lap from the pits, he’ll always make time on the person who’s stayed out on old tyres.
Graph 1 – Race History. The zero line is simply the race winner’s average lap time (total race time divided by the number of race laps). This is why his curve can go above the line if he’s lapping faster than his average, and below the line if he’s slower than his average or doing a pitstop.