If you take an interest in Formula One, then you are probably aware that the first stints of the Force India drivers defined the strategy for the race. Here, we take a look at why their progress at the start of the race made such a difference to the race strategies of everyone except probably Ferrari (who figured they just couldn’t use the option tyres) and Mercedes (who did a standard strategy anyway). Here are the Force India drivers traces from the first stint, with the intelligentF1 simulations (dotted lines):

So after an initial opening of the gap, the underlying pace of Di Resta (cross symbols) on the prime tyres could be simulated at about 0.4s slower than Sutil was managing on the options – although both drivers were a little inconsistent. Given that Pirelli were thinking in terms of 0.8-1s and the qualifying golden laps on the options were a full 2s faster, this came as a surprise to most teams. Indeed by the time we reached lap 10, the degradation of the options of Sutil could be seen in the laptimes, but Di Resta was going strong. With 61 laps to complete, and tyres good for little more than 10 laps, most teams did the maths and figured that two long stints on primes (as long as they lasted) would beat option-option-prime, with the extra flexibility of being better able to combat the high likelihood of a safety car.

As it turned out, Mercedes (who stayed with the original plan) were probably worst affected by the safety car having stayed on the options and made their second stops well before half-distance. Even without the laps under yellow, Rosberg (especially) was looking at a final stint on the primes almost as long as the two-stoppers. Using the intelligentF1 model, the strategy can be allowed to play out to see what might have happened in the event that the safety car did not come out. The dashed lines are the intelligentF1 model, which show the underlying pace of the car, and are matched to the actual data (solid lines) at the point Schumacher crashed. The stints that each car was on have been extended to 15 laps for options and 20 laps for primes.

The major difference between the Force India cars is that Sutil’s shorter first stint landed him in traffic (note slow laps 14-15 and allowing Di Resta through) . Key to the race between the Mercedes and the Force Indias then becomes whether the German cars could get past Sutil in their final stint on the options. If they were able to go past immediately, then they had the pace to just about squeak ahead of Di Resta after their final stops (if they could get the tyres to last long enough), but any delay would have meant that they would have had to overtake on track. Rosberg was unable to do this in the final stint in the real race. Schumacher was quicker than Rosberg, and would have stood a better chance, but he would probably have needed the team to let him through. This just shows that the margins of success and failure are incredibly small in Formula One. And that two stops, with two stints on primes was just (probably) the right strategyas Di Resta was likely (but not certain) to beat Rosberg even without the help of the safety car.

*In Depth Data Analysis*

Posted on October 4, 20110