There was something odd about Lewis Hamilton’s race at Silverstone. From a subdued looking eighth, he suddenly appeared in the lead as others stopped. Then he did a short stint on the soft tyres and dropped to 12th due to an early second stop – eleven laps after leading! And then he struggled to recover to eighth, passed easily by Schumacher (who he’d earlier passed) along the way. If he was really that slow, then how come he ever got into the lead?
This post is based on two bits of information coming together. Firstly, it is clear that Hamilton had good pace at the end of his first stint, and that this pace is different from the fuel-corrected pace on his final stint. In all the races I have done, there are some discrepancies, but rarely are they as big as this. Secondly, I read an article today which stated that Hamilton’s pace in the last stint was one second per lap slower than McLaren had expected due to the behaviour of that particular set of hard tyres. And that got me wondering. Can I verify McLaren’s statement against the pace Lewis showed at the end of the first stint. If so, can I figure out where he could have finished if he could have raced at his first stint pace?
Let’s start by looking at the race history chart. I’ve only included the cars around Hamilton, and I’ve highlighted the key points in Hamilton’s race.
What we can see is that from lap 14 to the point he is caught by Alonso (on his new tyres) Hamilton is actually faster on his old hard tyres than Schumacher is on his new hards, and about the same pace as Massa, also on new hard tyres. But by the last stint, he is clearly much, much slower. By modelling the race (slightly complicated by the low degradation of the hard tyres), we can see that if we match the pace of these fast laps, the gradient of Hamilton’s curve fit (dashed line) suggests that he should be much, much faster in the last stint (chart below).
I’ve extended the pitstop times to show the curve fit matching the first stint, and being in about the right place in the other stints (I need to do that mainly due to the time lost in the Alonso battle). The difference in the actual final stint of Hamilton, and his predicted pace from the first stint is massive. Indeed, the first stint pace would have been sufficient to have kept Grosjean behind him reasonably comfortably. So can I quantify this difference in pace? Well, by my calculations, I get that Lewis is about 0.7s slower across the main part of the final stint in comparison to what we could see from the first stint – and for the first five laps of that stint it is indeed the one second difference claimed by McLaren. So the story stacks up against the data, and that suggests a true underlying pace on the hard tyre which is slightly faster than Alonso, and equal to Lotus. It looks like there was something strange going on with the tyres in that last stint. As a small aside, Michael Schumacher’s middle stint was curiously slow in comparison with his final stint – in his case it was about 0.4s, which is still a very big difference in my experience. Usually, things fit within 0.1s, so I would suspect something similar happened with that set of hard tyres.
Now, if Hamilton’s pace was as it ‘should’ have been in the last stint, how could he have done? I’ve put that on the chart below, matching Hamilton’s fit to the last lap on his second stint to get the best estimate of only changing the last stint.
This suggests that he would have had enough pace to sneak ahead of Raikkonen (depending on what Lotus did to cover) and challenge Massa for fourth. And then we’d be talking about the mistake in fighting with Alonso as it cost him 1.5s which might have made the difference between being ahead of Massa or behind him. Oh, and a good save from a poor Q3 session.
Have McLaren fallen behind Red Bull and Ferrari? In the championship, yes. But in underlying pace, Red Bull may have been clearly the fastest car on the soft tyre at Silverstone, but on the hard in clear air, there was nothing between the red cars and the blue cars. And, strange as it may seem, the silver car which struggled home eighth.