F1: Strategiereport James Allen – GP von Spanien 2017

This was one of the best races from a race strategy point of view for years. Like last year’s Spanish Grand Prix, strategy decided the outcome, but the two main protagonists, Lewis Hamilton and Sebastian Vettel also surpassed themselves, with heroic drives, making it a truly memorable race

Here we will analyse the momentous decisions that dictated the outcome, at how the pendulum swung from one driver to another several times. And we will also look at how the lowly Sauber team managed to score its best result since 2015, with a very bold one-stop strategy, yielding four points for the team, which will prove very valuable. Before the race Pirelli said that three stops was a marginally faster strategy, but the key factor was the calculation on the difference between the soft and medium tyres.

This is because on Friday the gap looked enormous; some teams were reporting two seconds per lap difference between the compounds. But history shows that comes down on race day and Friday was also a tricky day with weather conditions, especially wind, so it exaggerated the appearance of a problem. Another consideration in Spain is that Virtual Safety Cars and Safety Cars are a rare occurrence, so they do not figure highly in the list of probable scenarios.

Vettel vs Hamilton: Phase one of the race – Advantage Vettel

This was a race where Vettel proved his value as a leader from the cockpit as on two separate occasions he made calls from the cockpit. Ferrari heeded one and didn’t heed the other, which is why they lost this race, as we shall see.

A few minutes after the start of Saturday’s qualifying session, Vettel was told to switch off his engine. A less experienced driver might have obeyed, but he questioned it, during which time the problem righted itself. So instead of starting on the back of the grid, he was able to fight for pole. He should have had the pole, but made a small error on his final lap.

But it didn’t matter as he took the lead at the start.

To do an optimum three-stop race you need to stop on Lap 13. Around Lap 12 Mercedes, who had Hamilton in second place, started to make moves that looked like they were going to pull the trigger on a stop. Hamilton was told to pick up the pace. At this point Vettel was secure in the lead and had a 2.2 second lead. That came down to 1.8s as he caught some traffic, putting him in range of being undercut, if Hamilton were to stop and use the performance of the new tyre to jump the Ferrari driver.

Up ahead was Vandoorne, so there was an element of risk for Vettel and Ferrari opted to pit him. The problem was that Ricciardo was inside the 22-second gap back to pit safely, which is why Mercedes didn’t go for the early undercut attempt. Memories were still fresh of Melbourne where Hamilton could not pass a Red Bull, but Vettel could and that swung the race.

Vettel duly stopped and then was able to pass Ricciardo easily. So it was clearly advantage Ferrari at this point.

Mercedes play chess with Bottas and then Ferrari gives them an open goal

Mercedes reacted by deciding to extend the stint for both Hamilton and Bottas. In the case of Bottas this was to prove the race-winning move, as the Finn was able to hold Vettel up for two laps, costing four seconds of race time.

In Hamilton’s case it cost him valuable time, but a combination of Bottas playing the team game and then an extraordinary mistake from Ferrari, handed the race back to Mercedes. On Lap 34 the Virtual Safety Car was deployed for Vandoorne’s car, highly unusual at this stage of a race in Spain. Past half distance, it meant that a driver could pit for medium tyres and make the finish.

Strategists look at the state of the damaged car, signs of any debris, whether cranes are involved, when assessing how long the VSC might be out for and whether it might turn into a Safety Car. This one looked straightforward, so likely to be only a lap or two under VSC, was the judgement of most. The saving in time difference between pitting under a VSC versus pitting at racing speeds in Barcelona is nine seconds. Vettel had a nine second lead over Hamilton (it would have been 13 secs without Bottas’ intervention).

There were three possible scenarios:  Both cars pit, which would favour Vettel; Vettel alone pits, which would also favour Vettel or Hamilton alone pits, which is the only scenario that favoured Hamilton. Vettel radioed the team to say that he felt they should pit him, but they decided not to. One of the contributing factors here was memory of Canada 2016, a race that Ferrari lost in similar circumstances, because they pitted as the VSC ended.

Mercedes knew that if they could pit and catch some of the VSC period, they could close the gap. They had no way to know when it would end. Fearful of a repeat of Canada 2016, the longer Ferrari left it, the less likely it was that they would stop. Mercedes pulled the trigger and gained some time but it wasn’t perfect as the VSC ended when Hamilton was in the pits.

But it won them most of the time and then Hamilton had a very strong out. Ferrari had to react and pit Vettel a lap later and when he came out, he was side by side with Hamilton. They raced brilliantly but Vettel just held position. Now the challenge for Vettel, on medium tyres, was to keep Hamilton behind him for long enough to take the edge out of the soft tyres Hamilton was using, much as Bottas had done to Vettel at the start of his second stint.

With these 2017 cars, the following car is more easily able to exit the final corner flat out than in past years, where an overtake on the main straight was therefore really hard, (for example with Raikkonen and Verstappen last year). But Hamilton was able to get the job done, while the tyres were still fresh and took the lead.

Ferrari thought about a Plan C, which was a third stop, but Mercedes kept Hamilton at 2.8secs, which covers off that opportunity. Vettel said afterwards that this race was like a bar of soap in the shower that you can’t keep hold of and it is true; this should have been his race and he had Hamilton where he wanted him before Ferrari presented him with an open goal. It will be interesting to see how punchy they are next time there is a VSC when Ferrari has control.

Narrow squeak for Sauber on VSC brings points bonanza

When you are a team like Sauber, that has the slowest car in the field on a track like Barcelona, you have to be bold. If you plan a safe two-stop strategy like the cars around you, the best that might happen is to beat one of them and finish 16^th or 17^th. So Sauber took a gamble, one that had a potentially big upside, but the downside would be limited by general expectations.

So Sauber approached the weekend with a single minded aim of doing one stop. This meant that the drivers approached the crucial Free Practice sessions with that in mind, when setting the cars up. The strategy relied on Wehrlein doing the first half of the race on a set of new soft tyres, which he did very well. The team was on target for a 10^th place finish ahead of Daniil Kvyat, but then the VSC intervened and fate presented the team with a rare opportunity to shine.

The VSC was deployed when Wehrlein was exiting the final chicane, less than two seconds from the pit lane entry. He was called in immediately; so late that he had to cut a bollard on the pit entry, which brought him a five second penalty, so this was not his fault.

If he had missed that chance to pit, he risked being mugged by all the cars behind and coming out behind Grosjean in 11^th place, who was seven seconds behind, which is less than the time gained by stopping under the VSC. So Sauber would have lost all chance of points. It was extremely tight but it worked.

The UBS Race Strategy Report is written by James Allen with input and data from several of the F1 team’s strategists and from Pirelli.