Bahrain Grand Prix: All-action race in prospect

Posted on April 21, 2012

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This has all the hallmarks of a race of the kind we saw in Turkey last year – but better, because the underlying pace of the cars is much closer. From the Friday data, and I haven’t seen anything which changes the view in the Saturday data, the tyres are struggling in the heat, and so a large number of pitstops and a very hard-to-follow, chaotic race is likely. Which means action – and probably confusion.

The race in China last weekend showed what can happen when the field is close. Pitstops drop you to the back of the pack, and a lot of time can be lost getting back to the front of the queue. Managing to get as much free air as possible counts a great deal. There is one significant difference in Bahrain, though. The loss of performance of the tyres here is very significant, which means that the cars on new tyres will have a huge performance advantage. And even if the car in front is going OK, it won’t be too long until they will have to pit for new rubber. I think that the penalty of stopping more times will be less as overtaking cars on older tyres will be simpler than we saw in China.

The performance of the cars on Friday suggests that the soft tyres will be looking at entering ‘phase 2’ degradation after about 8 laps (or about 5 laps on used tyres). Thereafter the cars  are losing pace at the rate of 0.5s per lap. So after 13 laps (or 10 laps on used tyres) they will be 2.5s per lap down on their early stint pace, and will either be heading for the pits or getting overtaken. This has major significance for the race. The medium compound tyres seem to be doing a bit better, reaching around 10 laps before entering a similar ‘phase 2’. The medium tyres are slower than the softs – but only just. The pace difference I can see from the back-to-backs in practice are of the order of 0.2s per lap – which would usually make new mediums faster than used softs. Unless a team thinks that they are much faster on the soft tyres, I think that we will see mediums being the tyre of choice in the race.

Let’s use these degradation figures to look at possible strategies, starting with a basic two-stop against three stop comparison – using the assumption of starting on used softs and changing to two sets of new mediums, and then a set of used mediums. The penalty for used tyres is very consistent at 0.3s per lap for most races, so I’ll assume that it is also the case here.

The simulated race history chart is shown below.

From this, if the tyre wear is as it appears from Friday practice, that two stops is not a viable option, and that we will see at least three stops per car. It’s almost certain that someone will try it, and track evolution is possible, but this is very different from the situation in Korea last year. There the evidence from the free practice sessions did not support the predictions of multi-pitstop races and intelligentF1 correctly predicted a two stop race. Here I find it difficult to imagine a two-stop race. To get the two stop race to be competitive, I need the soft tyres to be getting to about lap 10 (before phase 2) – with pitstops about lap 13, and the mediums to be lasting over 20 laps, with phase 2 not starting until 16-17 laps in. It’s possible, but it’s a long way from the evidence of Friday.

What about four stops? Well, this would require two stints on the soft tyre, which does not appear to be significantly faster. However, it can be seen that ‘phase 2’ is entered for each set of tyres in a three stop race in our prediction. So can it still be advantageous to stop for a fourth time? The race history chart below makes the same assumptions as the one above.

If my figures are reasonably accurate, then four stops may be marginally faster, but there will still be some ‘phase 2’ degradation on the soft tyres in the last stint. And some serious passing on track is likely to be needed. But it may work.

What do I think will happen? I would expect mainly three stoppers, and if someone can get the tyres to work well enough not to enter ‘phase 2’ then they will be looking very good. Williams looked the best in practice, but next was probably Grosjean. The black cars may be worth watching – especially as Raikkonen has saved a set of soft tyres – it could make a difference if he can go long in the first (or perhaps final) stint. I imagine that those with the option to start on new tyres will go for mediums for the opening stint, and may see if they can extend the life in order to only stop twice (still a long shot as far as I can see). As the pace difference between new mediums and used softs is small, the field spread may well be small, leaving the top eight out-of-sync with the rest of the pack. Interestingly, my simulation suggests that if the top eight get about 10 seconds clear, (which is reasonable for the first few cars) they might not be too hindered by the out-of-sync cars if they all go for three-stoppers. If the strategists can get a clear run, then it might make the difference between the very closely-matched cars.

After all this, we may see a dull two-stop race with everyone on the same strategy and Vettel keep enough of a gap to do what he did all last year. But I wouldn’t bet on it.

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