Spain race analysis

So far the 2016 F1 season has been great. Thanks to the new tire rules the races have been very interesting, if not a bit chaotic: in the first five races of the season overtaking has been more common than in 2011, the first year of DRS and Pirelli tires. The only thing missing was a real battle for the lead, as Rosberg had won four races without too much difficulty. If he'd selected the right engine mode at the start of the Spanish Grand Prix, he might have had another uncontested race win. Luckily for the spectators he didn't and therefore we could witness a cool battle for the lead instead of third place, resulting in a shock win.

After the Mercedes' had gone out, we were left with a battle between the Red Bulls and the Ferraris. The Ferraris had been fast all weekend, except for qualifying, and therefore they had to do some overtaking work in the race. They failed to make progress at the start. Vettel managed to get past Verstappen, but he was immediately re-passed in turn 3. Even worse, he was also passed by Sainz. Both Vettel and Räikkönen managed to get past the Toro Rosso after the re-start, but they had lost valuable seconds in the meantime. In clean air, however, they were considerably faster than the Red Bulls, who soon pitted. After the stops the top 3 was covered by only a few seconds. As the track is one of the most difficult tracks for overtaking, Ferrari had to come up with some creative strategy to defeat the Red Bulls.

The strategic possibilities were, however, limited. The tire allocation for the Spanish Grand Prix was soft, medium, hard. The hard tire was clearly the most unpopular tire; only the Renault team used it in the race. Therefore only the softs and mediums were a viable option in the race. In the top 10, all drivers started the race with 3 sets softs (used in qualifying), 2 sets of fresh mediums and 1 set of useless hards. This limited the strategic freedom further, as a 3-stop strategy had to use the soft tires in at least 2 stints.

Laptime analysis* reveals that the medium tire was, on average, the best tire in the race. Fresh softs were over a second per lap faster, but as the leaders only had used softs left, the grip advantage of the softs was only about a second. The soft tires wore out over two times as fast as the mediums: the tire degradation of the soft tires was about 0.22 seconds per lap, while the medium tires wore out at a rate of almost 0.10 seconds per lap. This led to a crossover point at 8.5 laps, suggesting that the medium tire was superior over the soft tire in stints longer than 17 laps. Given that the average stint length of a 2-stopper was 21 laps (the race essentially lasted 63 laps), the medium tire was the preferred tire.

Optimal strategy

2-stops: 15 laps on softs, two stints of 24 laps on mediums

3-stops: two stints of 13 laps on softs, two stints of 18-19 laps on mediums

Interestingly enough, the optimal 3-stop strategy would gain 21.6 seconds on track compared to the optimal 2-stop strategy. The pitlane losses were estimated to be about 21.5 seconds on average, so in theory both strategies were equally fast. Traffic would make the difference. Generally, a more aggressive strategy induces more traffic, but that's not always true. Employing a different strategy can be a great tool to get out of traffic. For some reason Ferrari didn't pit Vettel when he was close to the Red Bulls at around lap 25. This gave Red Bull the opportunity to pit Ricciardo on lap 28 to avoid the Ferrari undercut. Ferrari reacted and pitted Vettel in the next lap, which meant that he was still behind Ricciardo. Both drivers were now on a 3-stop strategy.

Meanwhile Red Bull left Verstappen out to cover a potential 2-stop strategy from Räikkönen. As it turned out, Räikkönen was indeed on a 2-stop strategy. Again, Red Bull pitted their driver one lap before the Ferrari driver. Interestingly, Vettel pitted just a few laps later in order to undercut Ricciardo. Red Bull left him out for quite some time so he would have a decent tire advantage at the end of the race.

After the final pitstops Verstappen was leading the race, with Räikkönen right behind him. Vettel and Ricciardo also had fresher tires, so a 4-way battle for the lead seemed likely. However, overtaking was still very hard, as Räikkönen found out. He couldn't get within 0.6 seconds in the last corner and that just wasn't close enough. Verstappen managed to stay ahead by a few tenths of a second at the end of the straight (about 20 meters), while Räikkönen was closing in at a rate of 25 km/h (about 7 meters per second) due to the slipstream and DRS. Behind them, Ricciardo was able to get a little closer to Vettel in the last corner, but the Ferrari engine was powerful enough for the 4-times world champion to stay ahead.

The final laps were nail-biting, but in the end, except for Ricciardo's desperate "dive bombs" and his flat tire, nothing much happened. Vettel couldn't close the gap to his teammate, who couldn't get past the Red Bull. So in the end Verstappen won the race, ahead of Räikkönen. The "first drivers" Ricciardo and Vettel lost out with their more aggressive strategy, as they couldn't regain the lost time in the pits. The next figure summarizes the race:

Race History Chart of the 4 front-runners.

The "trails" based on laptime analysis fit reasonably well:

Race History Chart and projections.

Räikkönen especially lost a lot of time in the first stint, when he was being held up by Sainz. Once in clean air he was very fast. In fact, he was the fastest driver in the race by a clear margin (almost 0.4 seconds per lap).** Vettel, however, was fast at the beginning of the race, but slower at the end of the race. He complained about his performance on the medium tires. His last stint was quite disappointing indeed, as he wasn't able to close the gap to the leader faster than he did. It also shows that his very short third stint on softs really hurt him. The Red Bulls seemed to perform better on the medium tires. Verstappen's final stint suggests that he might in fact have been faster than Ricciardo in the race, as his trail is well ahead of the projected line. However, in the final 10-15 laps he started to suffer from additional tire degradation, which slowed him down significantly.

According to the analysis, Räikkönen had the pace to win the race. If it wasn't for traffic he would have won the race by about 25 seconds, which really shows the importance of a good qualifying. Even from where he started, the predicted line shows that if he had been able to overtake Verstappen early in the last stint, he would still have been about 10 seconds ahead at the end of the race. Ricciardo's strategy was in theory good enough for second place, while Vettel was never going to beat Verstappen.

Predicted Race History Chart.

Räikkönen was almost half a second faster than Verstappen in the final stint. As it turned out, it just wasn't enough to overtake, as Verstappen didn't make any mistakes. In hindsight, if Ferrari had pitted Räikkönen a few laps later, he might have had a big enough speed advantage to overtake. The same applies to Ricciardo, who might have had a better race if Red Bull had delayed his final stop a bit more. It also would have prevented him from getting a flat tire in the penultimate lap...

Anyway, it was a thrilling race with a new winner. Thank you Mercedes!

* Only laps in clean air (more than 2 seconds behind another car) are used. Extremely slow laptimes are excluded.

** Driver speed:
1. Räikkönen
2. Vettel +0.35
3. Verstappen +0.36
4. Ricciardo +0.36
5. Bottas +0.99
6. Massa +1.08
7. Sainz +1.26
8. Gutiérrez +1.48
9. Pérez +1.48
10. Grosjean +1.53
11. Kvyat +1.55
12. Button +1.68
13. Alonso +1.79
14. Palmer +1.94
15. Ericsson +2.03
16. Magnussen +2.22
17. Nasr +2.28
18. Wehrlein +2.71
19. Haryanto +2.78

Hülkenberg and the Mercedes drivers had no (uncongested) laps. The typical margin of error of the estimates is 0.1 seconds.