British GP deciding moments

Here is a sector by sector analysis from the ten laps that decided the 2015 British GP. How the coming rain fell to different parts of the circuit and how it affected the race.

The analysis includes the top-8 cars and starts from lap 36 which was the first full lap after the virtual safety car period. By lap 46 everyone was on inters and there were no more place swaps after that.

Short summary of the action is that there was a brief shower around lap 38, Räikkönen (and Alonso, Ericsson, Stevens and Merhi) pitted then. Most cars waited until more stable rain started at end of lap 44 which proved to be correct. The cars who waited one more lap for pitting ended up losing a bit but not as much as the earliest cars.

Sector 1 times

Sector 2 times

Sector 3 times

Lap 36

Order is HAM MAS BOT ROS RAI VET KVY HUL, first full lap after virtual safety car earlier. Tires are probably bit cold but after SC but track is almost dry, some cars set their best S1 or S3 times.

Lap 37

Rain hits sector 2 after first four cars (HAM MAS BOT ROS) have driven through it. The following cars are 4–6 seconds slower in S2 compared to previous lap. Other sectors are still dry and some cars are even faster there than lap 36.

Lap 38

Now sector 2 is wet but other two sectors are still dry. All cars are 8–10 seconds slower than normal there. Vettel was 2.5s behind Räikkönen at the start of lap but driver S2 over 2s faster and overtakes in S3. Kimi has the slowest S2 of the top-8 but Hamilton is only 0.1s faster, Kvyat catches Vettel and is almost in his tail. Even if S3 is almost dry, Kimi decides to pit for inters.

Lap 39

Same continues, sector 2 is still the only wet part of the track. Hamilton continues to be 1–6s slower there than other cars with slicks and VET, KVY and HUL have really good speed but Räikkönen is 2s faster in S2 than anyone with slicks. This shows that had the rain increased at this point he would have been in a really strong position. Unfortunately S3 is still dry and Kimi with inters loses the 2 seconds he had just gained on the previous sector. Rosberg passes Bottas in sector 2.

Lap 40

Rain in sector 2 eases or stops, everyone is couple of seconds faster there except Räikkönen who is now 2s slower than his previous lap. One lap in dry sectors 1 and 3 have already worn his tires. Williams are now the slowest cars in S2 and Rosberg passes Massa there.

Lap 41

The track continues to dry, Rosberg with clear track is now catching Hamilton who is now the slowest car in S2 together with Räikkönen. However the trio Vettel, Kvyat and Hulkenberg are even faster than Rosberg. Kvyat has catched Vettel and is less than 1s behind him. One reason the cars behind are faster in S2 because they arrive there bit later and track has perhaps dried a bit more compared to the cars in front. Kimi continues to lose 3–4s per sector on the dry parts and is overtaken by Perez.

Lap 42

Sector 1 is now bit slower than before for later cars, perhaps some drops there. Sector 2 is now almost dry, Rosberg is faster there now than when he was behind the Williamses before the rain and he’s the fastest car in the track catching Hamilton by 2s. Kimi loses 7–9 seconds per lap with inters now.

Lap 43

Hamilton has 1s slower sector 1 than most other cars. Sector 2 however seems to be dry as Rosberg, Bottas and Kvyat drive their fastest times there. But the rain hits the track when cars are in sector three and this is the point when Hamilton and Vettel make their famous call to pit. Rosberg is 3s slower in S3 but later cars are affected more. Williamses are 5–6s slower, Hulkenberg 8s and Kvyat 12s slower (spin?) in just one sector compared to their previous laps. Kimi with worn inters is 4s slower.

Lap 44

Now the track is wet and Vettel is actually able to enter the track back from pits in front of Kvyat who had a spin. Rosberg only loses few seconds in S1 and is actually not much slower in S2 compared to Hamilton and Vettel in inters. Second sector is actually still less wet for Rosberg than His third sector however is 6 seconds slower than Hamilton had lap before when entering pits and this decides the winner. The cars with slicks behind Rosberg lose much more. Kvyat and Hulkenberg are 10s slower in S2 compared to Rosberg. Kimi with worn inters is 2s slower than Vettel and Hamilton who have new ones but manages to catch and overtake Perez who is still in slicks. Everyone who has not yet pitted comes now in for inters.

Lap 45

Massa and Bottas lost so much time in wet lap 44 that Vettel has now overtaken them. Massa is 4s behind Vettel and Bottas has fallen 11s behind his teammate in the process. Kvyat who was just in Vettel’s tail is now fallen 40s behind him in just two laps. Kimi spins when starting the lap, without that he would probably had overtaken Hulkenberg and possibly even Kvyat who now came out from pits just in front of him.

Lap 46

Everyone in inters now and in the order they will finish the race, speed differences from here on are much less dramatic between the cars. Kimi in significantly more worn tires loses 5–8s to others but luckily he has enough space to Perez behind him so he can take a “free” pit stop for new tires. For some reason lap 36 sector times for Kvyat are missing from the timing app.

Conclusions

Hamilton’s and Vettel’s pit for inters was really well timed. Interestingly on the lap they came in the rain had not actually intensified almost at all. On lap 38 when Kimi came in he and Hamilton did over 51.5 in sector 2, on lap 43 when Hamilton came in he did 40.9 which was actually his fastest sector 2 for some laps and this applies to the following cars as well. So there was nowhere as much rain during lap 43 compared to lap 38 earlier.

And when Hamilton came in to pits even his last sector time was not very slow, it was 27.8 compared to 27.2 by Kimi entering the pits (in dryish sector 3) on lap 38. All the other cars behind Lewis had a much slower sector 2 which makes it really strange that only Vettel decided to pit then. So looking at the times it was like Hamilton himself said, a perfectly timed stop. It didn’t rain almost at all when he went to pits, it rained when he came out.

Had the rainfall been 30s slower to arrive on the circuit Rosberg might have made it. Both he and Lewis did similar times in sector 2 on lap 44. Rosberg in slicks and Hamilton inters. In the end Rosberg came out from the pits 9s behind so following Hamilton to pits lap earlier would have not been a better option for him.

About Kimi’s call then. What was unfortunate there is that the rain fell only to sector 2 of the track and two other sectors remained dry. This destroyed his tires very quickly, had the rain even briefly fallen to the whole track his call might have been turned out to be a masterpeace but that was not to be.

Interesting here is that only two cars managed to get the pit call right. From all running cars at the time five cars pitted too early (Kimi, Alonso, Ericsson, Stevens and Merhi) and five lap too late (Rosberg, Massa, Bottas, Kvyat and Hulkenberg). Ericsson managed to pit again for slicks on lap 41 and again on inters on lap 42 (he was lap down at this point). This gave Alonso the opportunity to get points.