Much has been made of the fact that Kimi Raikkonen elected to save a set of tyres instead of making a second run in Q2, which left him 11th on the grid. As the race panned out, it seems that Raikkonen may well have decided not to run at all in Q3, and to start on a new set of soft tyres. The fact that he had a set of new soft tyres, and Grosjean didn’t, essentially defined their races, and determined that the Finn would catch and pass his French team mate. There are two reasons for this; the Lotus was much faster on the soft tyres than on the mediums (a full 0.8s) and the new tyres allowed Kimi to run long enough to be able to use two sets of the soft tyres, whereas Grosjean needed to use mediums after the first stint. Add to this that one of Grosjean’s sets of mediums had already been used in qualifying (about and extra 0.3s), and the tyre advantage of Raikkonen is clear.
The key difference between the two can be seen in the second stint. In underlying pace, Raikkonen is merely 0.1s faster than Grosjean. No more. But the advantage of being able to use the soft tyres in the second stint made a huge difference. Lotus pace on the soft tyres in the first stint is evident from the race history chart of the first half of the race (below) – indeed they are a whole 0.6s faster than anyone else (including Vettel) on the soft tyre.
The speed at which Raikkonen catches Grosjean in the second stint is down to the Lotus being much slower on the medium than the soft tyres. Interestingly, Webber and the McLarens lose a lot of time in the second stint, but they are disproportionately slow in this phase of the race – it could be fuel saving, or Webber could have had a rogue set of tyres (or be using a set of mediums from qualifying) – indeed Webber is much quicker on his mediums in the final stint. So although the degradation of the mediums is about 1.5 times that of the softs (it varies a bit, but 0.12s per lap for the softs and 0.18s per lap for the mediums fits most cars well), there was still a significant advantage in running two stints on the soft tyre. As we will see in the ‘Story from the Data’ tomorrow, there were very few teams confident enough in their use of the soft tyre to try this.
Red Bull figured this, and put both its cars on the soft tyre for the third stint. Their degradation was higher than Raikkonen on the medium, but in underlying pace Vettel on the softs was about 0.1s up on the Finn, although it wasn’t many laps into the third stint before the Lotus was the faster car. Once onto the final stint, both cars on mediums, their pace was very similar. This stint also shows that Grosjean’s pace was not far away from Raikkonen’s, and the intelligentF1 model fits show that their pace was consistent through the race. Therefore the difference in the Lotus cars performance was due to the tyre strategy – and Raikkonen’s bold call in Q2 allowing him to make full use of the pace on the soft tyre.
Worth noting is that Webber’s pace is much closer to Vettel in the second half of the race, as indeed Grosjean is to Raikkonen. The pace difference in the third stint is due to Grosjean running used mediums to Raikkonen’s new set.
As it happens, the fastest cars were indeed the Lotuses – Raikkonen was 0.7s faster than Vettel on the softs, and about 0.1s faster on the hards. But had he not saved his tyres, and run the race Grosjean ran, he would not have finished as close to the Red Bull in front. Much as talk is of a missed opportunity at the win, I’m more inclined to think in terms of Lotus having realised that they were seriously quick on the shorter-lived tyre, and devising a plan to maximise their use of that tyre in the race as it was so advantageous to them. They took a risk, went for it, and they nearly won the race. And had Vettel been running just 0.2s per lap slower (Webber’s pace), they would have.
intelligentF1 
Edson Framil
April 23, 2012
Raikkonen’s and Lotus gamble was only validated because he made all those places at the start, but i think he coiuld have challenged Vettel seriously for the win if he had got past Grosjean faster and if stayed a bit longer on his stint on the mediums… didn’t they called Raikkonen in too early? And to make things worse at the same time as Vettel did.
Anyway beatiful work as always! Thanks
intelligentf1
April 24, 2012
He did gain at the start, but if he had not got stuck with Massa for the first few laps, he would have got through better. I think that he would probably still have been second if he had stayed 11th at the first corner.
The last pitstop is hard to call. It sounds like Red Bull were just responding to Lotus. Lotus would have had to stop first to win – I think Red Bull’s pit crew reaction time is fast enough that they would have been able to stop when Kimi did. Stopping later would have given Vettel laps on fresh tyres – Kimi would have been closing the gap by a few tenths per lap as his last set would be newer – but he would have been 5s behind once he put them on. It would have come out about the same.
Bradley
April 24, 2012
Surely it’s easy enough to give Raikkonen – who can see Vettel ahead – the instruction ‘pit if Vettel stays out, or stay out if Vettel pits’. I don’t know why this instruction isn’t given more often – barring pitstop problems, pitting on the same lap as the car in front is the worst option in a two-car battle.
intelligentf1
April 25, 2012
Very true. And when the car behind is much faster (so will get ahead whichever way round they do it) it seems the obvious thing to do. Thinking about it, when the battle is just between the two cars, there is nothing to lose by doing things differently when you are the car behind – and nothing to gain (barring problems) when it’s done the same.
Warrior
April 23, 2012
“The pace difference in the third stint is due to Grosjean running used mediums to Raikkonen’s new set.”
They were both on new mediums in the third stint, if my information is correct. Grosjean used the used tyres for the first two stints. This observation may increase the gap between the performance of the two of them…
Nice post again btw, thanks! 🙂
intelligentf1
April 24, 2012
Yes, I read this too. But I have trouble getting this to fit the data. Grosjean’s fuel-corrected pace (the fuel model looks pretty good across all cars, so I think it’s OK) in the second and fourth stints match very well and he is about 0.3s off in the third stint – which suggests to me that the difference is in the third stint. The counter-argument would be that he killed his tyres quite quickly in the second stint which suggests that they were used (and he went too fast), and ran more slowly in the third stint to make sure that the tyres didn’t go off again. With more rubber down, he was able to go faster in the last stint. If I go with this, then I have Grosjean faster in underlying pace (on the mediums) than Kimi in stint 2 by about 0.2s, and slower in stint 2 by about 0.4s. This is pretty hard to assess as, if true, it probably means that they were also playing with engine modes.
nish
April 24, 2012
would you be able to estimate where di resta would have ended up finishing if he had gone for a 3 stopper?
intelligentf1
April 24, 2012
I have Di Resta at almost exactly the same pace as Ferrari, on both soft and medium tyres. So, given that he was behind at the start, all things being equal he would be behind at the end if he ran the same strategy. In fact, Hulkenburg was about the same pace as Di Resta (about 0.1s slower on the mediums), and so I can match Hulkenburg’s 3 stop race to the Ferraris, and it is pretty much the same (within 2s of Massa) after his bad first stint stuck in traffic.
Best guess is that he would have been between Massa and Schumacher. So two stops worked for him.
nish
April 24, 2012
well he was very lucky the tires just lasted till the penultimate lap. i felt it was a huge gamble considering what happened to Raikonnen in China, but I suppose by your calculations he actually had little to lose (at most 1 point) ?
intelligentf1
April 24, 2012
I think he did have little to lose. Even if the tyres had fallen 8 laps short, and he pitted, he would have come out just behind Schumacher and Perez with a huge new tyre advantage and strong underlying pace. I think that the worst they would have done was 9th (behind Massa). Which is where I think they would have been if he had three stopped. So I’m not sure that there was really anything to lose.
janis1207
April 24, 2012
Yeah.
All about tyres, tyres, tyres. Not so much about racing.
And it’s a pity. Schumi certainly had a point when he observed tyres are playing a disproportionally big role in F1 today.
intelligentf1
April 24, 2012
I will admit to strongly preferring tyres being dominant over aerodynamics (and that’s being an aerodynamicist). Then it was just fuel/pitstop strategy. At least we get passing on the track now, and there is the chance of having some racing. China may have been tyre dominated, but it was one of the best dry races for a long time.
Going further back – in the turbo era it was about power, in the mid-late sixties it was about finishing the race and being able to nurse the car home. Guess ’twas ever thus.
Edson Framil
April 24, 2012
I think it’s safe to say with a fair amount of knowledge now that the current generation of Pirelli’s work better at a higher window temperature, but a very narrow one as we sought until now. It was quite strange to hear Raikkonen saying that his tyres hit the cliff just at the time he caught Vettel, they should last a little bit longer…
and what about the Mclarens? Just got kept in traffic or they misunderstood the tyres at all?
intelligentf1
April 24, 2012
I must admit to being very careful when a driver says they hit the cliff. There are extreme examples (Korea last year when the Ferraris suddenly slowed by 4s per lap) where the tyres become seconds per lap slower. Then there is a more normal ‘phase 2’ degradation where the tyres lose about 0.5s, then 0.5s each following lap. Raikkonen did lose around 1s on the in-lap (third stop), and this might be ‘phase 2’ – but it might not. There is no evidence of a cliff – and certainly no ‘phase 2’ on his final stint. Di Resta also said the tyres were finished on the penultimate lap – but his last laptime was OK.
McLaren weren’t that fast – Hamilton was a little down on Webber for speed, and a little up on Button. Realistically they should have been 5th and 6th. But their tyres didn’t last long – there is evidence of ‘phase 2’ degradation on Hamilton’s first three sets and also on Button’s. They really struggled on the used mediums, and may have been better off doing what Red Bull did, and using a set of softs for stint 3. You wonder if they should have done four stops, although the stops didn’t go well either.