Bahrain Grand Prix: Why saving tyres made all the difference to Raikkonen

Posted on April 23, 2012

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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.

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