USA Grand Prix: Friday Practice Analysis

Posted on November 19, 2012


Not for a while has there been as confusing a set of data as this. We can get a very rough idea of who is quick, but in reality I don’t think that very much can be said from the Friday running – and there are two key factors which have come together to make this happen; the track surface and the tyre choice.

The track surface is clearly much less abrasive than had been expected – Pirelli are talking about ‘zero wear’ and an obvious one-stop strategy. This seems pretty obvious from the data; as in India the stints in FP2 are getting faster as they go along – and by more than any feasible fuel effect. It’s all about the tyres. It’s interesting to see that some teams are able to get heat into the tyres faster than others, and pretty much everyone is gradually getting into the tyre temperature performance window during the stint. It takes time as the track is not gripping the tyres (or the other way round) resulting in low wear and slow heat up. This results in less rubber going down, so the track improves slowly. Thus it is still evolving meaning that when the car made the run is also important in the assessment of the data.

So what we have is a comparison of stints in which the lap times are continually dropping due to fuel load, tyre temperature and track evolution, and it is not really possible to separate the effects of the latter two – but it can be seen that they are significant. If we add in that as the time runs out some cars have run quick laps just to see how much life is left in the tyre and, as in India, they are finding that there is a lot left in the tyre, it becomes really difficult to pick out the true pace of the cars. Is a short stint slower as the tyres haven’t heated up? How much is the effect of a run made earlier in the session? What is getting into the tyre window and what is pushing harder to see what is left in the tyre? How do you consistently pick the data which best matches the underlying pace of the car? And don’t forget, this is before any fuel load considerations. Oh, and it’s a new track with no data to fall back on.

So what am I trying to say? I can get something out of the data, but it is subject to much larger uncertainties than usual due to the very inconsistent pace of the stints. Have a look at the chart below – I have included the fit on the end of Kobayashi’s long run to show that the data on runs that long is understandable, so I think that the model is OK. But there is a lot of noise on the short runs.

There is no data for Hamilton, Ferrari, Ricciardo, Maldonado, Petrov, Marussia (Pic did a long run but it was fast/slow/fast/slow) and HRT.

So at face value (with no fits) it looks like Vettel is quick, Button/Webber/Senna are next up with Grosjean. Raikkonen is slower (but on a shorter stint) than Grosjean, with the Saubers and the Mercedes. Force India/Vergne seem to be taking longer to warm up their tyres, but Hulkenburg has some pace in hand judging by his last laps. Caterham are adrift – by miles. The true picture is not easy to piece together, but my best guess is (based on laps later in the stint):

Vettel fastest (+0.0s)

Button +0.3s

Webber +0.7s

Senna +0.7s (excluding last lap)

Grosjean +0.9s (longer stint than Raikkonen)

Rosberg +1.3s (note longer stint that Schumacher plays in his favour)

Raikkonen +1.3s

Hulkenburg +1.3s (excluding final lap)

Kobayashi +1.3s (note stint was earlier in session – may be faster)

Schumacher +1.6s

Perez +1.6s (shorter stint than Kobayashi)

Di Resta +1.7s (excluding final lap)

Vergne +2.1s (not short stint)

Kovalainen +3.8s

If this has any bearing on reality, then it suggests that Red Bull look good and that there is a similar gap between the top teams and the midfield as in Abu Dhabi. That gap is being filled, once more, by Williams – who appear be ahead of Lotus here. The battle for the minor points looks to be as fraught as ever, with Mercedes, Sauber and Force India closely matched.

Shame that I can’t really use the Ferrari data. The three laps Alonso did were fast enough to be competitive, so I would guess that Ferrari will be top six contenders at least, but little more can be said. However, Vettel must be favourite.