Playing with fine margins: A deep dive into race strategy from Nurburgring
The German Grand Prix at the Nurburgring featured three drivers in different cars closely matched on performance.
The German Grand Prix at the Nurburgring featured three drivers in different cars closely matched on performance. As the winner Lewis Hamilton observed, it was all about being perfect and not making mistakes and this was as true of the strategists and the pit crews as it was of the drivers.
In the end it came down to some inspired driving and finely balanced strategy calls. But further down the field we saw some varying strategies making a difference to the race result, particularly in the case of Adrian Sutil, who finished sixth ahead of the Mercedes and Renaults.
The key consideration in deciding the strategy in Germany was the performance on the slower medium tyre. If you were getting a difference between the soft and medium tyre of around 1.5 seconds then two stops was the way to go. If the gap was larger then three stops would be the answer with a short final stint on the medium tyre.
Tyre life turned out to be better than expected in Friday practice, so for many teams two stops looked a good option. But then heavy rain on Saturday night cleaned the track and that might have pushed some people towards three stops in the race believing that the track was very green. In the Bridgestone days this would have led to tyre graining, but that didn't happen with the Pirellis in Germany. Instead what happened was that the track had less grip so the lap times were slower and this took less life out of the tyres, but the green surface didn't damage them.
The battle at the front
Bearing all of this in mind, even the three-stoppers at the front ran almost a two-stop race in terms of stint lengths. Webber for example, did 26 laps on his third set of soft tyres. They didn’t want to put on the prime tyre, so they stopped as late as possible. Two cars pushed it to the extreme – Vettel and Massa – they pitted for medium tyres on the penultimate lap!
Among the leading trio Webber, who lost the lead to Hamilton at the start, was able to undercut Hamilton at the first stop by pitting first on lap 14. Webber was 0.5s behind the leader Hamilton when he made the stop. A very fast turnaround by the Red Bull crew, plus two very aggressive out-laps by Webber got him into the lead. He pushed hard to open a gap but Hamilton was faster in sectors one and three and Webber knew then that it wasn't going to be his day.
Having pushed his tyres too hard early on, Webber’s pace wasn’t good at the end of the second stint. He tried the undercut again, but it didn’t work out. Hamilton and Alonso, on option tyres that were two laps younger, were able to increase their pace when Webber pitted. Webber’s second stop was 0.8s slower than his first stop and the end result was that he was down to third.
As for Hamilton and Alonso, they came in together for the first stop but Hamilton pitted a lap earlier second time around. Alonso's in lap was 0.7s faster than Hamilton's and the pit stop was 0.4s faster. What was interesting was that Hamilton's out lap on fresher tyres hadn't been significantly faster than Alonso's on worn tyres, which defies the principal of the early stopper having the advantage.
Alonso came out of the pits in front but the Ferrari's weakness in not warming the tyres up straight away meant Hamilton was able to pass him in Turn 2. So the strategy had worked for Ferrari on paper, but not in reality.
Webber had managed the undercut at the first stop but stopping first didn't work for either Webber or Hamilton at the second stop. This can partly be explained by the damage the extra duel weight does to the tyre in the first stint, which diminishes by the time of the second stop and by the durability of the Pirelli soft tyre.
As for the timing of the final stop to the slower medium tyre, that was all about looking for evidence and it came in the form of Vitaly Petrov and Kamui Kobayashi. Maldonado had gone to the medium early on lap 35 but his lap times were inconsistent. When Petrov went to mediums on lap 46 and started setting personal best sector times on his second lap on the tyres, and Kobayashi went faster than his team mate who was still on old soft tyres, it was clear to McLaren that the time had come to take the medium tyre.
Webber was out of the picture by now, 8 seconds behind second place Alonso. McLaren pitted Hamilton on lap 51, but Ferrari did not react, leaving Alonso out there for two more laps, Ferrari was more concerned about its pace on the harder tyre. Hamilton's pace was good straight away on the medium and the race was in the bag. Webber tried to stay out longer and jump them but he was coming from too far back and he couldn't get close.
Sutil vs Rosberg
One of the highlights of the race was the performance of Force India with Adrian Sutil. He put together a perfect weekend and the strategy team got it just right. The result was he finished in sixth place, ahead of both Mercedes. He qualified 8th, two places and 0.8sec behind Nico Rosberg's Mercedes. To beat him from there is quite an achievement.
Sutil vs Rosberg was a good example of two stops working out better than three. Force India were one of the teams for whom the simulator said that two stops was as fast as three and with one less stop to make there was less risk of losing time in traffic or with a poor stop.
Sutil stopped on laps 22 and 48, Rosberg on laps 14, 36 and 53. Their lap times were pretty similar in the first stint, but thereafter Sutil had the measure of him. The Mercedes is heavier on its tyres and Sutil closed the gap to Rosberg from four seconds down to nothing by the time Rosberg made his first of three stops. The Mercedes is a faster car, as was proven in qualifying, but their hands were tied by the heavy tyre use and Force India were able to beat them with 10 seconds to spare at the end.
Sutil was very impressive all weekend and he managed to find good consistency from the medium tyre. He was straight onto the pace after he went to mediums and set his fastest lap of the race when they were nine laps old. Many teams found it hard to get temperature into the medium tyre in the cool temperatures.
Getting the fuel load right
The possibility of rain on race day had quite an influence on fuel strategy in this race. A lot of people under-fuelled their cars in the belief that it would rain and that forced a lot of people to save fuel late in the race. That’s why Alonso eventually finished four seconds behind Hamilton, before then running out of fuel on the slow-down lap.
After making that mistake and under-fuelling Hamilton at Silverstone, McLaren didn’t make the same mistake twice!
(The UBS Strategy Report is produced with input and data from the strategists of several F1 teams.)
Race History Graph
Below is a graph showing the race history. It shows each car and the time delta between them and the race leader. So the laptime is encapsulated in it, but it also shows progress at different stages during the race because a cars slope will change if it goes faster or slower. You can also see when someone is clearly being held up in traffic.
The zero line is simply the race winners' 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.
LAP TIMES GRAPH
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