British Grand Prix: Ferrari’s Soft Tyre Struggle

Posted on July 9, 2012

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It was a surprise when it became evident that Mark Webber was taking chunks out of Fernando Alonso’s lead, even though it was clear about five laps before the BBC commentators noticed it. Well before the move was made, it was obvious that the Red Bull was going to win the race. But until we reached lap 40 (with just 12 to go), there was no sign that we would have a winner other than Alonso.

For all the talk of graining, or the tyres not lasting, there was a much more basic explanation for the fact that Red Bull overhauled Ferrari. Quite simply, the Ferrari was not fast on the soft tyres. It was (whisper it) as slow as the McLarens. The hard tyre was another story – only Vettel and the Lotus cars were as quick as the Ferrari on that tyre. But on the soft, the red car simply did not have the pace. Simple as that.

A quick look at the race history chart (below) shows that there is no major drama in Alonso’s trace in the final stint.

Alonso has great pace in the first stint on the hard tyres, pulling a gap. Vettel is stuck behind Schumacher/Massa and loses touch. He gains the places with an early stop, loses a little time in traffic, and then (interestingly) is slightly quicker than Webber for the rest of the race. The middle stints are very even with all the cars on the hard tyres. But then, the final stint, and Alonso is a full 0.5s slower than the Red Bull (according to my fuel-corrected model fits) on the soft tyre. This puts him at the same pace as Hamilton’s mid-race seven-lap soft tyre stint. With the Red Bull essentially showing identical pace on both tyre types, and Ferrari preferring strongly the hard tyre, it seems slightly odd that his first stop was as early as lap 16. I understand that he could do 14 laps on the soft tyre at the end with no problem, and indeed he did, but given the pace of the Red Bull in the middle stint, their pace in the final stint is easily predictable. Ferrari must have known that they were unlikely to hold on.

So what could they have done differently? Well, first let’s look at the model fits of their races.

The gradient matching is pretty good. The degradation of the hard tyre is about half that of the soft – the soft about matches the gain from the fuel effect (very high at Silverstone) and the stints clearly get faster with the hard tyre. This is much clearer in this race (on this tyre) than is usually the case. The second stint for Webber is behind the fit as I have used the same pitstop time loss for each, and Webber’s pitstop/outlap was about a second quicker. The fit for Webber’s second stint is not too bad, although it isn’t as clean as for most cars. Exactly the same fit is used for his stints on the hard tyres, so I’m happy that it is representative of his race. Alonso’s fits are very good indeed.

Good fits are nice because they allow us to play. What if Alonso had waited another few laps before his second stop – say he went to lap 41? Well, it would have been close:

I must admit I think that the result would have been the same, but it could well have been a last-lap pass. So the suggestions that holding off a few laps before the final stop are correct. It would have helped. What about delaying the first stop as well?

I’ve fitted the curve to allow for the same time loss behind Hamilton at the start of his stint (which he probably would not have had).  In this case, the soft tyres being new at a lighter fuel load would have allowed Alonso to have a faster pace, sufficient to keep him ahead of his pursuers. It seems Ferrari could indeed have won this one just by running a shorter stint on the slower (for them) soft tyres.

I’ll be back later in the week, with a look at who was fast on which tyres – some were faster on the softs, and some on the hards. The pecking order is very different on each tyre type…

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