Insight: Could Hamilton have won staying out and how Bottas got away with it // F1 News // James Allen on F1 ? The official James Allen website on F1
POSTED BY: JAMES ALLEN | 03 NOV 2015 | 6:43 PM GMT | 87 COMMENTS
The Mexican Grand Prix had no effect on the outcome of the drivers and teams’ world championship, as both were already sealed, but it did provide some fascinating talking points and a boost for the Williams team, which bagged a first podium since Monza.
A new Grand Prix venue always provides a fresh challenge, but with limited running during Friday practice high track temperatures in race day and an extreme altitude of over 2,000 metres, there were some unforeseen challenges to deal with.
Mercedes took its 10th one-two finish of the season, but Race Strategy was at the heart of the big talking points coming out of this race, especially the team orders around the strategy switch at Mercedes. We will analyse them in detail here, with the help and input of of several of the leading teams’ Race Strategists and our own JA on F1 technical adviser Dom Harlow, former chief operations engineer at Force India.
The heavily revised Hermanos Rodriguez circuit has a track surface that appeared to give low tyre degradation, but in fact it was quite significant as the race went on. Although tyre graining was an issue for many until enough rubber had gone down in the race, the higher temperatures in fact reduced the effect of graining. Meanwhile the low air density at altitude meant that the cars were travelling at speeds of over 360km/h and that brake cooling was critical for many cars.
Pirelli tends to be quite conservative on new tracks and brought the medium and soft compound tyres; teams knew even from the limited practice running they got, that this was likely to be a one stop race, with between 45 and 50 laps expected to be the limit for the medium. However as temperatures soared to 56 degrees before the start of the race, there were doubts about precisely how long the tyres would last on a long run.
Why did Mercedes change strategy and could Hamilton have won by staying out?
The key moment of the Mexican Grand Prix came early in the second half of the race, when Mercedes decided to switch to Plan B, which was to make a second stop for a new set of medium tyres. Hamilton questioned it, but having analysed this carefully, would Hamilton have won the race if he had been allowed to stay out?
The interesting aspect of this, which has not been widely discussed, is that Hamilton had experienced higher wear than Rosberg on the tyres during the race, so he had more to gain from this precautionary stop than Rosberg. At this point there was no way of knowing that a Safety car would come out five laps later. But without the Safety Car the Mercedes drivers would have been trying to do around 45 laps on the mediums, on a track that was ramping up quickly in grip and speed.
Another aspect that has not been reported in the coverage of this story is that this rapid track improvement masked the tyre degradation, which was what caught Force India out on Perez car (see below). At one point Hamilton did a faster lap on the medium tyres than he had done in the first part of qualifying, which is highly unusual and shows how fast the pace was in the race as the track improved.
The Strategy call to pit the Mercedes came as a precaution, in case there was a Safety Car later in the race. If a Safety car were to be deployed at a time when the Mercedes were caught out by it in the wrong position on track – if they had just passed the pit lane, for example, then they would have lost the race.
So once they had built a 27 second gap to Kvyat, it was obvious that changing the tyres was the right move; if you don’t have to risk running the tyres to the end of the race for 45 laps, then you don’t do that. You pit and change them, any team would do the same in Mercedes’ situation, with that advantage.
The team decided to play it safe and pit both drivers. In hindsight it might have been better to pit Hamilton first, to avoid the controversy which arose as he did an extra lap while questioning the decision. Then again, he would have almost undercut Rosberg if he’d been given the first pit stop, which could have been controversial in its own way.
To be fair, Hamilton clearly had limited knowledge of why Rosberg had stopped and perhaps assumed that his rival was in trouble with tyres, whereas he felt positive about his tyres. He saw an opportunity to challenge for the win – one he was keen to take, because for all his bravado after winning the championship and teasing Rosberg for the ‘gust of wind’ which was blamed for the German’s mistake in Austin, the fact is that Rosberg has now fixed his qualifying issues and has out-qualified Hamilton four races in a row.
Hypothetically, had Hamilton stayed out and not followed the instruction, he would have been able to lap in the mid 1m 22s, while Rosberg would have been able to do 1m 20s. So in the five laps before the Safety Car the gap would have come down to around 8 seconds. Hamilton would then have pitted under the Safety Car, but he’d be putting himself in the hands of a pit crew, whom he had disobeyed, to turn him around quickly…
If he’d tried to stay out, then at the restart he would be racing with a tyre offset to Rosberg of 16 laps, which would have meant a fairly easy overtake for Rosberg to win the race.
Bold Williams and Bottas luck out with Safety Car
There have been times in 2014 and 2015 when Williams has been accused of not being aggressive or ambitious enough, but this was not one of them. The season’s third best team got a well deserved podium thanks to playing it cool on strategy, taking risks and taking the opportunities presented.
They got onto the front foot with Valtteri Bottas at the start, moving from 6th to 5th after problems for Sebastian Vettel. But he was then held up by Daniel Ricciardo.
But their simulations showed that they would not be able to make the distance with one stop, so they made a decisive move early on Lap 8 to get off the soft compound tyres, which they struggled with and onto the mediums. Bottas said after the race that he believed it might be possible to make it to the end on that set, but it would have been a tall order and their simulations pre-race had suggested that the medium may last up to 50 laps, not 63! He rejoined 14th but picked up places as other drivers pitted over the next 20 laps.
In any case, he had to survive a collision with Kimi Raikkonen, but then gained from being able to run in fourth place, a few seconds behind Daniil Kvyat, right up to the deployment of the Safety Car on Lap 51.
This gave him a chance to switch to a two stop strategy, a free pit stop and a chance to challenge Kvyat for the podium at the restart. But he almost missed the chance, as he did not come in on the first opportunity, but on the second lap, losing 12 seconds to Ricciardo in fifth place. This almost cost him, but he got away with it and managed to emerge just a second ahead of Ricciardo.
Although at a disadvantage because he was obliged to fit mediums, whereas Kvyat took softs, he knew that he would have a chance to attack down the long pit straight at the restart.
With Williams able to reach 360km/h and Red Bull only 347km/h, he made the most of the opportunity and stole the podium place. The pain of Red Bull’s season and situation was summed up in that one move.
Perez rides his luck – again!
In Russia Sergio Perez gained his fifth F1 podium with a stunning performance, based on making a set of soft tyres last a long time while still maintaining strong pace.
On home soil in Mexico, he tried to pull off a similar trick, this time with a set of mediums going for 53 laps. He was running 8th when the Safety Car came out on Lap 51. The effect of the Safety Car at that point of the race was to allow everyone to convert a one-stop strategy to a two stop with a minimum time penalty for the second stop.
The Force India team decided to gamble on leaving him out, rather than stopping, in order to gain track position on Massa and Hulkenberg, who were 20 secs and 17 seconds ahead of him, respectively. The calculations were a little awry and it didn’t work out, as he was still behind them both, but now with Verstappen close up behind him with a new set of soft tyres.
He managed to hold position to the flag for an emotional 8th place, meaning that he has now scored 53 points in the seven races since the summer break.
The UBS Race Strategy Report is written by James Allen with input and data from several of the leading teams’ strategists, from Pirelli and from JA on F1 technical adviser Dominic Harlow
RACE HISTORY AND TYRE USAGE CHARTS
Courtesy of Williams Martini Racing – Click to enlarge
A graphic representation of the Race History in terms of the lap times of each car. It shows the relative pace of the cars and the gaps between them in the race. Upward curve is good pace, downward curve demonstrates slower pace. Sudden drop is a pit stop.
Look at the difference in pace between the Mercedes (light blue) and the Red Bull (purple) cars. Also look at Vettel’s (red line) pace shortly before crashing; the upwards line is comparable with Mercedes, showing what might have been had Vettel got a clean start and ended Lap 1 in third place.
Look carefully at Hamilton’s pace at the end of each stint, just before each stop. He has strong pace still on the tyres.
Click top link for charts