This weekend’s Abu Dhabi Grand Prix was very interesting from the point of view of Race Strategy, with six different strategies in the top ten finishers.
Pre race predictions of two stops were the norm, but there was a wide variety of alternatives tried, with Mark Webber doing three stops en route to fourth place and Paul di Resta scoring a points for ninth using a one-stop plan.
We also saw McLaren pull off something very audacious at the first stop; they pitted Jenson Button on the same lap as the leader Lewis Hamilton, with only a 12 second window between them! Button’s total time in the pits was a second slower than Hamilton’s but it was a very brave thing to do and showed the team’s confidence on the day.
All three podium finishers did the predictable strategy, of running two stops with a longish middle stint on soft tyres of around 24 laps before a short final stint on the mediums. Ferrari tried to use the easier tyre use of the car with Alonso to stay out three laps longer than Hamilton and have a go at jumping him at the second stop, because they saw that the McLaren driver was losing time in traffic after his second stop.
It nearly worked. He was only 3 seconds behind when Hamilton pitted on lap 40 and did two very strong laps on worn tyres before pitting. He was about to catch the HRT of Ricciardo and didn’t want to lose time, so pitting then when he had pretty much the right gap (21 seconds) over Hamilton made sense.
But unfortunately for him, HRT called their stop at the same time and he was held up behind Ricciardo on the way into the pits and a slightly tardy change cost him the chance come out ahead. But even if he had managed it, Hamilton would have probably passed him as the McLaren was superior to the Ferrari on medium tyres. This scenario is precisely what happened in Germany earlier this year.
But Ferrari must have felt that they had enough margin at that point to call Alonso in, as he still had good pace from his tyres.
Mark Webber has done some racy strategies this season, mostly to get himself out of traffic, which is something his team mate Sebastian Vettel hasn’t had to do much as he’s usually been out at the front.
Webber started out the race planning to make two stops like the podium finishers. He lost a position at the start to Alonso. However, with Vettel retiring he was racing Button for a podium finish until he had a very slow pit stop on lap 17, which cost him six seconds. It was an unusually messy stop for the Red Bull team which tops the league table for stops this year, along with Mercedes.
Although Button had KERS problems, the gap was still significant back to Webber after this. Webber was racing Massa for fourth place. The Brazilian wasn’t on great form in Abu Dhabi and it was well known that Ferrari were very wary of the medium tyre as they had struggled to get performance out of it in practice, as they have all year.
When Webber pitted again for soft tyres on lap 35, it was clear he had switched strategy. But it wasn’t realistic to think that it would help him get Button, as to do that would require him to have gained 31 seconds in 20 laps over the McLaren.
There have been suggestions from some in the team that he needed to stop to get off his second set of tyres which wasn’t working for him, but after passing and being repassed by Massa he was sitting behind the Ferrari and the switch allowed him to try something different to get ahead of the Ferrari. There was a big gap in the traffic for him to slot into and use the pace of a fresh set of tyres.
It worked, but even if he had stayed behind Massa and done a conventional two stop, he would have easily passed him anyway once they both went onto the medium tyres because the Ferrari was so slow on them. Massa made life easier for Webber with a spin and by being slow generally.
Massa has been lucky that the gap between the Ferrari and the Mercedes is as big as it is because it means that despite being six tenths of a second slower than Alonso he still finishes in fifth or sixth place.
Many fans have wondered why Force India, having qualified both cars strongly in the top ten put Paul Di Resta on a one stop strategy. Di Resta ended up at least where he would have been – ninth behind Adrian Sutil – but the strategy didn’t give him a chance to challenge his team mate. The medium was slower than it needed to be on race day to make a one-stop work.
If you analyse the decision making here, you can see why they did it. Force India’s plan was to put one driver on the one-stop plan and the other on a two-stop plan. Locked in a battle with Sauber and Toro Rosso over sixth place in the championship, which is worth many millions of dollars to them, they were more or less forced to cover off the possibility of their rivals putting one driver on a one-stop strategy and hitting the jackpot if there was a safety car, of the kind we saw last year in Abu Dhabi.
The data showed a 50% chance of a safety car and if one of their rivals had managed to get a free pit stop and been able to run most of the race on the faster tyre, they could have cut into Force India’s points lead. This possibility had to be covered off.
The midfield teams race in a different way from the top teams; the leaders are constrained by starting the race on their qualifying set of tyres and secondly they don’t take risks because they have the car performance not to need to.
There is a significant gap between the top three and Mercedes and then between Mercedes and the midfield and this gives them a margin for error.
So they would never gamble on a one stop in case the medium tyres don’t perform, but for the midfield it’s all about gaining track position and gambles often pay off as we’ve seen this year.
So it was a smart move by Force India’s Dom Harlow and his team. Having qualified strongly, Di Resta’s plan cut the midfield pack off from Sutil – by the time the German stopped on lap 15 he had a 15 second lead over the nearest midfield challenger.
And if there had been a safety car Di Resta would have been the first car on the road to benefit from it. This is a great example of the depth of Strategic thinking that goes into planning a race.
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.