Usually, I’m not big on the effects of track evolution during a Grand Prix. That’s because I can see the effects of the track rubbering in from the data in the opening laps (between 3 and 9 laps at most races) and then the behaviour is pretty much constant for the rest of the race. However, in Canada, the data shows big track evolution up to about half-distance. How quickly the cars were able to use their optimum grip (so the effects of track evolution became unimportant) made a big difference – especially in the case of the race winner.
These track evolution effects explain quite a few things; the significantly higher degradation in the first half of the race, the pace of Perez and Vettel on the supersoft option tyres at the end, and how Hamilton got his 3s lead. That the evolution was significant is easy to demonstrate. Fuel-corrected the pace of Vettel on the options in the last few laps was a full 1.7s faster than his pace in the opening laps. Yes, there is an effect of tyre conservation, and a possibility of fuel saving, but even still this is a very big difference. This is reasonably consistent across cars who used the same compound of tyre early and late in the race, except in the case of Button, who only gained 0.4s.
The race traces of Hamilton, Alonso and Vettel are shown in the chart below. On underlying pace, there is nothing to choose between the model fits for each. What is different is how quickly they reach this pace – in the highlighted part. Hamilton is much closer to the race pace than the others straight after the stops – he was 0.6s faster the lap after he overtook Alonso, and this gap gradually reduced over 7 laps until their pace was the same. But by this time, the gap was there. Part of this is tyre warm up, but the effects are similar for cars with different age tyres at this stage of the race – so it seems most likely that there is an effect of the Ferrari needing more rubber down to get the best from the tyres.Vettel was able to use the grip more quickly than Alonso as well, but not enough to get past (mainly because the Red Bull is slow in a straight line). You can make arguments that Alonso was saving tyres for a one stop, but it was never a winning strategy.
On the chart I have added the model fits for Hamilton and Alonso. Hamilton laps at the same fuel corrected pace in the final stint as at the end of the second stint. I have also added the fit of Alonso on the assumption that his tyres held out to the end. Hamilton gets him with about four to go. It would have been harder to get past (and Vettel as well), sure, but I don’t see that Alonso would have held on. He would have been second, but Hamilton was (barring errors) always going to win. I am surprised that Vettel did not stop earlier (within a couple of laps of Hamilton) as this became apparent very quickly. What would have been interesting then would have been if Vettel had gone for the option tyre (Hamilton was on the prime) as my best guess of the pace gap is order 0.6-0.7s per lap in the second half of the race. That could have won Vettel (or indeed Alonso) the race. I admit to being surprised when Lewis took on primes for the final stint – it could have cost.
In the chart below I have added a fit for if Vettel repsonded to Lewis taking on prime by taking options on the following lap based on his pace in the final laps. Now that would have been close. Not sure that the Red Bull straightline speed would have got him past, though…
Out of interest, I have also done a fit for the degradation of Alonso’s tyres in the final stages. It’s a simple quadratic fit, but it looks pretty good. All it shows is that from lap 57 Alonso got slower by about 0.2s each lap – by the end of the race this was a loss of 2.5s on the pace he was running when Hamilton stopped. He lost something of the order of 18s on where he ‘would have been’. I make it that it would still have been better to stop even with only 4 laps to go if he took option tyres. It’s amazing that he didn’t stop when Vettel did – or even the lap before as his tyres began to go first. Personally, I don’t see this loss of 0.2s each lap of pace as a cliff – it’s not sudden, but gradual, and there is plenty of time for the team to respond. Red Bull responded late, but they responded. Ferrari did not.
So another great race, and unlike Monte Carlo there’s a huge amount of interesting data – not least on the races of Grosjean and Perez. I’ll look at them in the next article, and I’m also planning to do a regular check of Friday pace against race pace as again it was a pretty good reflection of the race (note the Force India slump) despite the difference in temperature.
intelligentF1 
Tictac
June 12, 2012
I’m not sure the Friday stints were particularly representative where they? Maldanado looked no racier than a Toro Rosso and the Mercedes were quite average. great analysis again thanks.
intelligentf1
June 13, 2012
Rosberg was oddly slow in the first stint, but the rest was about 0.2s from Hamilton – which is consistent with Friday. Maldonado I have about 0.5s down, similar to Toro Rosso/Force India so I don’t know what happened to him (we can always blame track temperature for an easy get out). Interestingly, Webber was about right, and Vettel (on primes) was also about right. Perez/Grosjean were both quick too – but not as quick as in the race.
Problem is you can see what’s good only in hindsight… and how accurate you really think you can be with the Friday data. If the cars were less closely matched, it would be much easier (and much less fun).
Craig
June 13, 2012
Given how quickly Vettel was lapping on supersofts in the last 6 laps, in hindsight why didn’t McLaren fit supersofts to Hamilton’s car at his second stop? Surely they would have held up for some 20 laps?
Also, Di Resta really suffered this race – I’m sure at one point he was p5 or p6.
I’m also curious, as I’m sure the rest of the F1 world is, as to what is going on with Button and why he is having these pace problems?
intelligentf1
June 13, 2012
I was surprised at the time that Hamilton didn’t go for supersofts at the last stop. As Perez did 30 laps, and Hamilton did the first 17 laps on them, 20 laps at the end of the race would not be expected to be a problem. If Alonso had stopped and fitted supersofts…
The Force India was fast in qualifying, but the race simulation on Friday was not fast. Their race was consistent with that – they gradually worked their way backwards. Only about 0.5s off the pace, mind.
They claim Button has set-up problems. My guess (and it is a complete guess with no back up!) is that the McLaren has a narrow window where it is perfectly balanced and Jenson can’t get it to his liking except in some conditions. The car can go fast, but you have to chuck it a bit. Lewis seems to be happy with armfuls of oversteer and still gets the pace. Looks to me like they’re trying something different with the setup, which is making it worse. Jenson was nearly 2s off Vettel on the supersofts in the second half of the race – Caterham pace.
Craig
June 13, 2012
Yeah as am I, given how much the track rubbered in during the first half of the race. Makes you wonder if McLaren were being deliberately cautious? Or had information stating otherwise? If Alonso and Vettel had pitted one or two laps later than Hamilton, I believe he would have been third at the end of the race…
Interesting about Button’s set up problems – although I think some of it has to do with Button’s driving style as it seems like the drivers who are slightly more aggressive on their tyres heat them up much quicker therefore being able to pull away earlier before the oppositions tyres come into the zone. I will bring up the point of Barcelona – look at Button’s race there, the track temperature was around 35-40 degrees wasn’t it? And he still could not get heat into the tyres! Surely that can’t all be set up problems? Even in the last stint of the race he had much fresher tyres and never made an impact on Lewis which was surprising.
Also, Jenson’s current predicament reminds me of Suzuka last season with Hamilton being at a loss as to why his tyres went off so much quicker than those around him, and why he couldn’t maintain their pace too.
Given the nature of Silverstone, which of the two McLaren drivers do you think will come out on top against each other?
intelligentf1
June 14, 2012
I think that if Vettel/Alonso had stopped within a couple of laps of Hamilton and put on supersofts, I would have picked Alonso/Hamilton/Vettel as the finishing order – if Fernando could get past. Would have been some finish though…
For Jenson, I don’t know. Part of it is confidence – I think that knowing you’re not being able to give your best costs 0.5s before you start. As far as I can see on the tyre window, it costs 0.5s (ish) if you’re not in it – but I don’t think it’s more than that. It could be as simple as they have made some changes to the way they run the McLaren which they have figured in the simulator and Jenson can’t drive it, whilst it works for Lewis. We just don’t know – and worryingly it seems Jenson is a little confused too.
The thing about track temperature is that I’m not sure how much of a factor it is in getting heat into the tyres. The mechanism (as I understand it) is that energy generated by the tyre slipping on the surface is dissipated into the rubber in depth as heat. However, if you slip too much (sliding) then the heat can be removed with the surface layer of rubber (and so not be transferred) – this process applied to lateral slip (cornering) and longitudinal slip (traction). The relative proportions of the energy needed to be generated to heat the tyre (basically the rubber heat capacity/thermal conductivity) and the initial tyre temperature (don’t they come out of blankets still?) are not known to me. If the track is warmer, then less heat is needed, sure, but I’m not convinced about how much of a factor that is. It could be that the warmth of the track changes the response of the rubber and thereby changes the slip energy, which is dependent upon the vehicle dynamics. Does a hot track suit Lotus because they can’t heat their tyres, or beacuse it gives their car a balance which means that it heats its front and rear tyres to perfect balance? Wish I knew. Maybe Jenson should paint his tyres white to stop them radiating heat away…
Right now, you would have to go with Lewis for Silverstone of the McLaren boys. I guess Jenson will be spending serious time in the simulator – if he can figure his issues out, then he could be a threat. He’s a quality driver – he’ll be back soon enough.