2011 Formula One Pirelli Tyre Analysis

[jez101]

Credits: Sushifiesta, Tooncheese. This is a team effort.

The 2011 Season
This year we had a new supplier in this pivotal area. Bridgestone had seen F1 as a way of proving how hard wearing and consistent their tyres were – great congruence with their brand values no doubt, but to the detriment of the sport. Pirelli came in with a fresh attitude – to improve the spectacle and raise their profile, they adopted an aggressive approach. They delivered a range of tyres designed to wear out.

Clearly, Pirelli don’t want us to think that their road tyres wear out, so this was a brave approach. I can only imagine the board meetings where they discussed this, but the result was fascinating. It gave us all a reason to talk about Pirelli which at the end of the day is why they spend money on Formula 1. They gave us ‘the cliff’.

The cliff. The point where the tyres give up and you fall off. We heard a lot about the cliff after the tyres were first introduced to the teams in Abu Dhabi in late 2010. When everyone rocked up in Melbourne for the start of 2011, the expectation was that cars would be like lemmings, trundling around until suddenly falling off the cliff.

It wasn't really a cliff though. The data looks more like a slippery slope where grip fades hampering acceleration and lengthening braking distances so the car goes progressively slower. There are not too many examples where the tyres were fine one lap and gone the next – the deterioration was progressive.

In some places the cars got slower quite quickly, especially in Malaysia as shown in the first chart. The horizontal axis (on all charts) is scaled to fit a 60 lap race, so 1 lap of Monaco (race length in real life is 78 laps) is marked down as 0.77 of a lap. A tyre is one lap old at the end of its first outlap and if used in qualifying is on its fourth lap on the 1st lap of the race. Breaking the race into 4 stints (3 stops), means doing around 18 laps on each set (4 lots of 15 in the race + 3 on each tyre for qualifying).

Malaysia was chaotic but even after two races though, there was strong evidence that teams would quickly adapt to the new situation. How they did adapt tells us a lot about Formula 1 and how quickly it moves on. By the time we got back to Abu Dhabi for the 2011 race, the cliff was long and distant memory. The talk was all about avoiding the prime tyre instead.

Teams had figured that by making the softs last, not only could they go faster for longer on the yellow tyres, they could also avoid the prime tyre too. We will describe how they got there over the coming days...


About this thread
The tyres on a Formula 1 car are the only part of the car in contact with the road - Felipe Massa and his wobbly wing being the exception that proves the rule

We know tyres are important, but how important are they? We heard an awful lot in 2011 about tyre wear and the undercut, but what do they mean? In this thread, we will be analysing the tyre performance in detail – charting how the tyres performed at each (dry) race. The data helps to explain many of the things we saw on track in 2011 from Hamilton’s victory over Vettel in China to why the Indian Grand Prix was so dull.

To start the thread, we will tell the story of the season and show how the exciting races in the spring gave way to the humdrum we saw in the autumn. The simple fact is that drivers worked out how to make the tyres last and their strategies learned the lessons from some early mistakes that we will illustrate.

Over the coming days, we will steadily add more and more charts and our thoughts on what they are saying, but this is a forum, not a monologue. We want you to contribute what you think you are seeing too and ask questions and raise possibilities to explain what we are seeing.

As we go on posting, we will compare how drivers adapted to the tyres and learned to deliver optimum performance – there is evidence that driving style and the driver’s personal setup is at least as important as the car itself in how the tyres are managed.

Once all that is done and dusted, we will look ahead to 2012. In December’s F1 Racing, Paul Hembery is quoted as saying “next year’s hard tyre is not so far off … this season’s soft tyre” which is great news as it will bring back the dynamic we saw in the early races this year. We will will look ahead and speculate at what this might mean – the circuit characteristics clearly play a significant part in tyre degradation and we will also look at this once we have most of the information out.

Before we go too far though, a word of caution. There are many thing that the data does not explain because we filter out ‘incidents’ of all descriptions: pitstops, outlaps, blue flag laps, laps in traffic where the biggest chunks of time can be lost. The analysis looks purely at the tyres and how their age affects the driver’s pace. A driver can be blindingly quick, but if they keep having strange laps where they lose time, you will not see it in the data.

 

[jez101]

Continuing... The steep degradation seen in Malaysia was gone by the end of the season as The Abu Dhabi Grand Prix chart in the last post shows. This is the second type of chart used in the analysis and it shows four drivers (varying from chart to chart) in blue, red, black and green.

The fatter lines are for the option tyre, the thinner line is for the prime, so in the above HAM, ALO & WEB are all faster than BUT on the option tyres, but Jenson’s prime tyre lap times show that he held onto that tyre for 20 laps without any performance fall off.

The yellow lines show the field average – often these yellow lines will be slightly above the other four as the effect of the not-so-new teams pulls the lines upwards. It is the gradient of these yellow lines that is important, because a steeper line means quicker degradation. The data plotted is fuel adjusted and filtered as described above and we are also plotting the fuel adjusted points that are used to generate the trend lines so you can see the variance for yourself.

The contrast between Malaysia and Abu Dhabi is the real story of the year. It shows how the teams got to grips with the new Pirelli tyres very quickly, especially the yellow, soft compound. Sauber and Renault were the first to see some longevity (in Australia as you will see shortly) but couldn’t deliver it consistently.

In addition to being able to get life out of their tyres, the teams quickly learned how to use the 6 sets they were given. The mistakes they made learning the right strategy made for very entertaining races, but as the spring turned into summer, the strategy mistakes disappeared. After Button comfortably beat Webber & Alonso in Spain by doing 48 laps on his options compared to Webber's 29, the way forward was clear. After that, even when there was some degradation (like Japan for example), the impact was minimised.

To be continued!

 

[jez101]

Australia

Malaysia saw the nightmare scenario, but coming into that race after Melbourne, a lot of people were wondering what all the fuss was about. Australia saw some degradataion, but certainly no sign of a cliff.The vertical scale of this type of chart is going to be standard throughout the analysis, between -1s and +5s per lap. Zero for any given circuit is the peak soft tyre performance.

As you can see in Melbourne the peak lap on the hard tyres was quite quick, but as we saw in each of the first five races, the "hard" tyre degraded more quickly than the "soft" for the first 10 laps.

The chart shows VET (blue), HAM (black), BUT (green) & PER (red). Vettel is faster than Hamilton throughout – Lewis seeing a real problem with the hard tyres towards the end of his 21 lap stint. Button’s hard tyre times compare favourably to Lewis’ but Jenson’s race had been ruined by a poor start and a tangle with Massa (none of which will show up in this data), ending up just 6th even though there was evidence of strong pace.

In general, teams were conservative – perhaps relieved that there was no cliff, they went for a combination of 2 and 3 stops. It is interesting looking back at this when we come onto discussing the undercut because the opportunity was undoubtedly there to exploit it in Australia.

The chart for the leading runners above also includes Perez’s data because his hard tyre run (the thin red line) is so remarkable. Not only was he much quicker than he had been on options (thick red line), but he was quicker than Vettel, Hamilton and Button on the same tyres. Plus, he kept the pace going to deliver quite some debut.

It was a trick he tried again a few times, without ever managing to replicate the results so effectively and you have to wonder if the illegal part of Sauber’s car wasn’t a factor too because Kobayashi also had good life from his tyres in the same race.

In the race / tyre chart type, you can see all the cars on one of the compounds (in this example the options). Here are the same lines as in the Grand Prix chart (VET, HAM, etc above), alongside all the cars in the field. You can see Kobayashi’s thick white line for the option tyre is flatter than the field, for example indicating he held onto his times better than others did. Contrast this with Barrichello (turquoise) and Algersuari (thin purple), who seem to have taken the grip early and suffered as a result.

This chart also shows Petrov’s drive to 3rd place – he also found much longer life in his soft tyres that day. Heidfeld also bucked the trend, but his raw pace was nowhere that day, starting from 18th, he finished 12th.

Heidfeld’s off-weekend is again seen clearly here (thick yellow). This chart is again showing Perez’ prime laps and the remarkable times compared to everyone else’s on the same tyres. Kobayashi & Buemi also seem to have found life (the Moose especially so against his team mate on both prime and option tyres).

Leaving Australia, no one can have been expecting what happened next. Malaysia was pure carnage (from a tyre point of view at least), as we shall see .

 

[Galahad]

This is fantastic! I'm delighted to see the drivers all the way down the field included, I'm sure this will be fascinating to follow their fortunes. Congratulations to all involved, looking forward to the next instalment.

Can I make one request - in the heading at the top of each race, would it be possible to put which compounds were the Prime and Option for that race?

 

[jez101]

Malaysia

The tyre degradation in Malaysia was hugely significant. Maybe it wasn’t a cliff, more like a slippery slope, but the hard tyre suffered such that after only 15 laps you were already 3 seconds per lap down compared to a new yellow tyre. The soft option tyre did much better, but even it was a major problem.

The Grand Prix chart for Malaysia shows VET (blue), ALO (red), HAM (black) & HEI (green). Alonso must have wanted to cry - after nine laps on the silver tyre, he had lost 2 seconds.

Vettel won, even though Hamilton had more pace it seems. Lewis was 8th in spite of being quick because he didn’t maximise his tyres. In this second chart BUT (green) is shown alongside HAM (black from previous chart for reference), WEB (blue) and MAS (red).

Jenson finished second in the end, like Heidfeld, hanging on to the option tyres even when they were 15+ laps old and 2s + slower. Doing a few more laps like that was better than doing the laps at the end of the hard tyre stint instead, or stopping an extra time.

Malaysia was to see the steepest degradation curves of the season, with only Spain fighting for that honour. The Toro Rossos, Williamses and Mercedes suffered most. Looking at this, you would have thought that Lewis would have walked it, but he didn’t.

We didn’t really understand it yet, and neither did the teams, so the chaos made for an enthralling spectacle. Hamilton had to do 4 stops after he went too short on his option tyres, trying to switch before he found the cliff. It didn’t work – after the race, he said,

"It was as terrible race. I started second and I came eighth. I tried my best. I had four pit stops and the tyres didn't last. I stopped before everyone else when I could have stayed out for a couple of laps more.

"Then the wrong tyres were put on. I had the option instead of the prime. For the last stint I had an old prime which didn't last and I had to pit. It was very poor strategy but there's nothing I can do."

Strategy is not just about going fast, it seems. Lewis burned all three sets of options in the first 25 laps, so he had to do 31 laps on the prime that was 1.3s slower. Going fast throughout the race is much more important than pace itself. Button was second in Malaysia despite having a tough time with his options – looking at the option graph, you would not think he was fast enough to finish that high but as in Australia, his McLaren did much better on the primes than his team mate.

Jenson’s second place in Malaysia makes much more sense when you see the advantage he had on the prime tyres. The prime tyre in Malaysia was hard for everyone, but Alonso’s line really stands out. His tyres gave up 2s a lap between their second and eighth laps. Ferrari were well publicised for their problems on the harder tyres, to the point where there was a conspiracy theory going around that the introduction of the medium later in the season was designed as a Ferrari booster.

Although there is clear evidence that Ferrari struggled badly in places with the hard tyres, they did not fare that much better on the mediums either as we will see. It is also noteable that there were other races where the Ferrari did ok on the primes, like China.

 

[jez101]

Can I make one request - in the heading at the top of each race, would it be possible to put which compounds were the Prime and Option for that race?

Each race will have a deg chart to start and this is colour coded

red, yellow, white and black for supersoft, soft, medium & hard

 

[sushifiesta]

Nice work jez and tooncheese. It's a long long time ago now that we started this and I can't really take any credit for the latest results! I'm very impressed that you've managed to extract such clean curves in the overall prime vs. option plots.

If I had the time I might try something like giving each circuit a 'degradation' rating out of 10, or a set of degradation coefficients (e.g. of the form ax^3 + bx^2 + cx + d or whatever fits the curves best). From that I could probably try to adapt code I wrote ages ago and you'd end up with a tool that should be able to predict the best strategy for each race (excluding the effects of weather, traffic etc.). If someone could extract an equation for a line of best fit for each compound at each circuit, I might be able to find the time to try it over christmas if there is interest.... in reality though I know how much worlk all this sort of stuff takes and I should probably try to restrain myself!

Great work guys!

 

[mjo]

Absolutely fantastic work guys! This sort of analysis is what makes CTA so special. Malaysai was extremely chaotic! Was that the high temperatures and humidity which varied the degredation so much from OZ or do you think that it was just the style of track? Because as far as I can remember, Pirelli didn't change their tyres in the first two races. And by Singapore, where there was also high night temperatures and humidity, the teams had got the act together.

I somehow can't see SKY giving this in-depth coverage!

 

[jez101]

If I had the time I might try something like giving each circuit a 'degradation' rating out of 10, or a set of degradation coefficients (e.g. of the form ax^3 + bx^2 + cx + d or whatever fits the curves best). From that I could probably try to adapt code I wrote ages ago and you'd end up with a tool that should be able to predict the best strategy for each race (excluding the effects of weather, traffic etc.). If someone could extract an equation for a line of best fit for each compound at each circuit, I might be able to find the time to try it over christmas if there is interest.... in reality though I know how much worlk all this sort of stuff takes and I should probably try to restrain myself!

The curves that you see are now 2nd order polynomials (ax^2 + bx + c), generated by fitting the raw (filtered) data points, so in short, I do have forumals for all the lines you are seeing and yes, you could (if you want to ) work out the optimal strategy for each circuit. There are certainly some cases where a 3rd order or even a 4th order line would be a better fit, but I can't say which ones at this stage. For now, it is all 2nd order forumals just for simplicity

 

[jez101]

If anything isn't clear and needs some (better?) explianing, please do ask - even if you use a private message to do so to save my embarassment when you tell me I have done something wrong

Someone already did just that, to ask for a fuller explanation of how the charts are created and what on earth Poly (VET Option) might mean on the Grand Prix chart. There, the simple answer is that the lines are polynomial curves (for Vettel's option data!) generated using Linear Regression. If maths isn't your thing, the phrase "line of best fit" might make more sense than that mumbo jumbo jargon.

Essentially what we have done in Excel is (once all the strange laps are discarded), plotted the data points showing the fuel adjusted lap time (y axis) against the laps on a tyre set (x axis). You have to tell it what order of polynomial curve you are looking for (order 1 is linear ax + b, order 2 is ax^2 + bx + c, order 3 is ax^3 + bx^2 + cx + d). There is a convenient formula that gives you a, b, c etc as raw numbers using LINEST.

The data is actually Vettel's China option laps and the fuel adjusted points themselves are the little blue triangles. As you can see there is some variation from one lap to the next (for example lap 10 is ~1.4s slower than optimal, while lap 11 is only ~0.8s slower). Remember, the horizontal axis is the numbers of laps on a tyre set, so it is quite possible for a driver to have three points for the 6th lap on options.

The lines on this chart show how various trendlines would show the line of best fit to the data set. There is an indicator of how well a line fits called the R Squared value which, although often criticised as leading stattos to ignore the randomness in an event and devise high order polynomials that makes the line fit the data (whether it wants to or not) and deliver an R squared of 1 (perfect fit). In these cases, the following R Squared values apply to these trendlines in this one chart (Vettel, China, Option).

Linear: 0.838
2nd order poly: 0.895
3rd order poly: 0.908
4th order poly: 0.910
Exponential: 0.802

For now, I am sticking with 2nd order lines because it is one less variable to carry around from sheet to sheet

 

[sushifiesta]

Nice explanation. Like you hint at even though the R-squared values for the higher order polynomials (particularly 5th order and above) are higher what you often find is that if you use the equations to make predictions beyond the range where you have data they are often wildly wrong. In other words, with higher order polynomials you can make the line go through more points but you end up with a shape that doesn't represent what's actually happening at all.

The other nice thing about polynomials is that by setting some of the coefficients to 0 you end up with a lower order polynomial. So a 2nd polynomial, ax^2+bx+c, becomes a linear function bx+c by setting a=0, so you are in fact testing multiple types of function.

 

[jez101]

China

Tyres were the critical factor in Shanghai. This was not because their behaviour was particularly different (their profile in other early season races was similar) but because in China, a tyre strategy mistake cost Vettel and Red Bull the win.

Vettel was faster and made his tyres last longer than Hamilton but he did not maximise them: Vettel did too many laps on the slower prime tyre in his attempt to make a two stop strategy work. Hamilton stopped three times and this time got it right. By the time he caught Vettel, they were both on the hard tyre, but crucially, Vettel’s tyres had done 7 laps more.

The first Grand Prix chart for this race shows VET (blue), ALO (red), HAM (black) and ROS (green). Rosberg was in the mix that day - certainly Mercedes' most competitive showing of the season - and actually led 14 of the laps. Button was also in the hunt, and was ahead of Lewis for much of the race. Rosberg, like Button, faded on the prime tyres, even though they went for three stops. Hamilton overtook them both as he found much better performance than them on the hards.

Note: the pass happened on lap 52, which was Vettel's 20th lap on the tyres and Hamilton's 13th. After that event, both cars slowed considerably as you can see from the points beyond that on the chart.

In China, Alonso and the hard tyre worked better together than in Malaysia – degradation was ok, even though there was no pace. This time though, it was the options which troubled Fernando so he mirrored Vettel’s 2 stop strategy and fell away towards the end of the race for the same reasons as Vettel – too long on the slower tyre. It cost Fernando even more than the world champion: Alonso was 7th.

The other story in China was Mark Webber (red), plotted alongside VET (blue), HAM (black) and BUT (green). Whether it was arrogance or stupidity, but Webber's Red Bull got knocked out in Q1 after his prime tyre time left him 18th. The silver lining was that he had three brand new sets of options for the race.

Webber wisely started on the hard tyre and got them out of the way racing the midfielders (without ever recording an unobstructed lap which is why there is no line for WEB prime). In fact he got to 15th on lap 4 and stayed there until binning the hard tyres on lap 10.

With the hard tyres on everyone else’s car, Webber had 2s a lap on Button and Rosberg as he hunted them down near the end. Button’s primes started slightly better than Nico’s allowing him to overtake, but they fell away horribly. As he chased Rosberg on lap 39, Button did a 1.40.6. By lap 53, as Webber hunted him down he did a 1.42.4 (raw, unadjusted times. With fuel burned off, you would expect him to be 1.5s faster after 15 laps).

When tyres degrade all sorts of things happen to the race dynamic: if you pit, you are going to be quicker when you come out, if you can pit earlier, you can get ahead – 2011 brought the undercut into our living rooms. Equally important was to minimise the running on the slower tyre. After Vettel's choice cost him the win in China, teams learned their lesson.

China really makrs the point where teams started to figure out the strategy. In the next two races (Turkey and Spain), we saw the last two races where tyre degradation was a dominant factor.

 

[gethinceri]

You've made my head hurt.

 

[jez101]

You've made my head hurt.

Grab some asprin, I have only just started

 

[gethinceri]

I'm reaching for the gin.

 

[jez101]

Sebastien Buemi vs Jaime Alguersuari
These two have just lost their jobs, quite suddenly and surprisingly to many, including the drivers themselves. A lot of discussion is about whether they had done enough to keep their drives. They kind of had to beat each other to save themselves and perhaps what happened was that they were so evenly matched, that this was not possible. Toro Rosso had to keep them both, or axe them both, perhaps?

But what does the data tell us about how they compared?

Remember, we have taken out all the laps where other cars are in the way, so this is just a look at pure pace. I have plotted their times from the curves that I have been able to generate. The times are therefore from the line of best fit as described above. I have only "allowed" the time estimate if the lap was within the boundaries of the curve which is set by 'where the raw samples start and stop'. In other words, if a line starts on lap 5, it is because we don't have data from laps 1 to 4. similarly, if it stops after 7 laps, it's again because there is no real data the other side of it.

In this comparison, only points are plotted where both drivers have valid samples for the lap in question.

Basically, if the point on the line is positive, driver 2, in this case Jaime, was faster on the given lap (6, 12 and 14, with intermediate points ignored). These downward trending lines tell me that Buemi was certainly faster towards the end of stints, at most circuits. In terms of raw pace though, it seems to slant ever so slightly towards Alguersuari with more lines starting above the dotted line.

It kind of backs up the theory that they both lost because neither of them won. The Moose needed more raw pace and Jaime needed more staying power?

 

[jez101]

Turkey

After Hamilton’s success over Vettel in China, teams started to aggressively chase the undercut. With refuelling, we had the opposite (I guess we should call it the overcut?) – hang on out there because you will be slower when you come out with full tanks. Now cars are quicker after a stop, which encourages them to stop either to attack of defend track position. Turkey showed why the refuelling ban works beautifully with rapidly degrading tyres to make for hugely exciting racing.

Turkey broke all records for overtaking and it didn’t even rain! What happened was a combination of DRS and some very racy strategies throughout the field– most drivers were 1s a lap or more slower after 10 laps and no one went long, not even the midfielders.

When reading these charts, remember that they plot the age of the tyre, so a set that is brand new is on lap 1 on the first lap of the race (or out of the pits). A set of tyres used in qualifying is on lap 4 on the first lap of the race or outlap (and we drop the first lap / out lap etc from the time analysis anyway so lines often start on lap 5).

Remember we are also scaling the axis and what is important is that to break the race into equal lumps, the options will have to do 18 laps each for a 3 stop or 23 laps for 2 stops. Any less than that means more time on the harder tyre, which costs race time even though most teams have been able to use new prime tyres in races.

Alonso, Webber stand out as being significantly quicker on the primes than anyone else, although by then the race had been won by Vettel on his option tyres.

The Turkish Grand Prix chart has picked out VET (blue), ALO (red), HAM (black) and BUT (green). Webber and Alonso had quite similar stories though, so only one is shown.

What is noticeable from a tyre degradation point of view is the flattening of Vettel’s, Hamilton's and Button’s option lines. Alonso starts quite close to Vettel and then loses time as his tyres fade. Hamilton starts slower than Alonso but then is faster from lap 12. Lewis only finished 4th in this race, but it may well be that he and McLaren learned something important in Turkey about how to keep the tyres going for longer.

What you had though in Turkey was a difference in tyre performance of 2s or more a lap after only a quarter race distance – cars who had just pitted were flying past cars that were still holding on. This same difference in performance had been seen in the first three races, and clearly by Turkey, everyone had worked out that you could overtake by pitting earlier - or by having fresh tyres and DRS when chasing someone down. It made for great racing and even complaints from the purists that overtaking was too easy.

Perhaps it was too easy, but what seems to have happened is a perfect storm between tyres and DRS leading to crazy differences in closing speeds both in the catching and overtaking phases. All this mashed up with racy, undercut strategies that burnt the tyres, causing steeper degradation later in the stint led to a crazy race.

More was to come in Spain, but reflecting back on Turkey, it seems now that it was a pivotal moment. It was the first time any of the big teams had extracted some longevity out of the tyres. To be fair, none of the other drivers had consistently found any life before then either, but the Saubers and Renaults had hinted at finding a way to make the tyres last.

Turkey was about the undercut, but it was perhaps also its heyday. Shame , it was good for racing – there was still a bit more to this story, which was learned in Spain - but the lessons from the Turkish race were highly significant throughout the remainder of the season.

 

[jez101]

Malaysia was extremely chaotic! Was that the high temperatures and humidity which varied the degredation so much from OZ or do you think that it was just the style of track? Because as far as I can remember, Pirelli didn't change their tyres in the first two races. And by Singapore, where there was also high night temperatures and humidity, the teams had got the act together.

I don't think the track temperature or humidity are as much of a factor as other things. If anything Malaysia was unusually cool (29 deg track temp). Other high degradation races had a range of temperatures (Spain 43 deg, Turkey 30 deg). However, it was even hotter in Monaco (46 deg), Valencia (45 deg), Italy & Brazil (both 43 deg) and there was much lower degradation.

Himidity doesn't seem to relate much either, it was humid in Malaysia (high deg) & Abu Dhabi (low deg) but low humidity in Barcelona (high deg) and Monaco (low deg).

I have plotted the track temp against a meaure of degradation (based on the laps it takes to lose 1s/lap performace). On that measure, Malaysia has better wear than Spain, but Malaysia degradation was kicking in later than in Spain, but then more steeply.

If there was a relationship, you would be able to see it in these charts - there would be a straight line of dots implying that as temperature or humidity increased, so did tyre wear. These are much more random plots, so it's hard to say there is a link.

 

[jez101]

Spain

Undercut-mania all came to a bit of a grinding halt after Spain when Button’s 3 stop beat Alonso and Webber’s 4 stop strategies, even though tyres were wearing quickly and Webber and Alonso were a lot faster on the option tyre. What happened was that Alonso & Webber pitted too early, trying to undercut and defend against it and left performance in their option tyres. Four stops means two stints on the prime and in Spain, the hard prime was 2s a lap slower. Webber did his last lap on the option tyres on lap 29 of the race, leaving the last 37 to do on two sets of prime rubber.

BUT (green) did significantly more laps on option tyres (48) than WEB (blue) and ALO (red), so although he was slower, he beat them. Spain wasn’t all about tyres though. We also had Vettel vs Hamilton, the sequel. Could Lewis repeat his heroics from China? No, we know he didn’t… this time Vettel did maximise his tyres, even though Lewis was just as quick.

There is one lap of the whole season that I want to highlight. It is Vettel’s lap 21 of 1:27.394. I know that wasn’t his fastest of the race, but allowing for fuel it was 3s faster than the official “fastest lap” was fuel-adjusted. To put it in context, Vettel on lap 21 was a full second faster than anyone else on the track at the time and only four other cars got into the 1.28s. The lap was on a new set of option tyres that Red Bull had saved from qualifying, Hamilton was yet to stop and Vettel was chasing him down.

In this phase, Vettel was using his newer tyres to build a gap to Lewis. At the start of this particular phase of stops, Vettel had been a few tenths ahead, at the end of the phase when Lewis emerged, Hamilton was 4 seconds behind. Hamilton was able to use his newer tyres to catch up, but not even DRS and a slight tyre advantage could get him past.

One of the most noticeable features of Barcelona is quite how far apart the teams and drivers are there. You might think the more testing they do there, the closer they would all be, but perhaps it shows that what matters most in F1 is perfection and at Cataluna you see all the extra polishing.

The other noticeable thing about the Spanish Grand Prix this year is how far apart the primes and options started (2.2s). Spain was the last time we saw the hard tyres until India and Spain was also the last race where tyre wear was a major factor. Maybe the hards were an important factor in the early races being exciting, but somehow this seems doubtful.

What really seems to have happened is that the teams got to grips with the yellow tyres en masse over the next three races (including Canada which generated meaningless degradation charts due to the changing circuit conditions). There was already evidence that some were cracking it, Vettel, Hamilton, Button, Perez, Kobayashi, Buemi and Petrov all managing well on occasions. By making the tyres fast and long, teams could run three stops comfortably while minimising the running on the hard tyre.

 

[jez101]

The Yellow Tyre
The yellow soft tyre was at every race (although in Brazil it was a different version). It is natural then that the teams were happiest on this, even in races when the supersoft was available. More polishing in evidence here too, then J.

This chart shows the summary of performance across the field. It is set against the peak time (square marker) from a soft tyre at each of the tracks and shows lap 18 (3 stop, diamond marker) and lap 23 (2 stop, circle marker) benchmark degradation. Notice, Turkey and Spain had no cars doing that many laps on the tyre, so those lines are projected from laps 19 and 20 respectively.

You can see that degradation was still apparent as the season wore on, but at about half the rate seen up to Barcelona. On some tracks, the yellow tyre was just too good. The worst were Monza, India and Abu Dhabi where it certainly did not behave like an option tyre.

In Monaco and Korea the yellow tyre was the prime and its profile did fit that role well. In Singapore, especially, the race was livened up by the tyres degrading where the contrast with the supersoft worked well. Japan had similar levels to Singapore, but was a bit of a bore with the yellow set alongside the white medium tyre. It seems that there is more to mix than simply having an option tyre that wears out: the contrast with the prime is also important.

The green line shows the difference between prime and option’s peak pace. The orange line plots the same difference at 18 laps and the blue at 23 laps. In an ideal scenario the orange lines would be close to zero indicating a cross over in pace over a given lap, and significantly negative by lap 23.

This is the same data from a different angle, plotting a line for each race through the difference between prime and option at peak, lap 18 and lap 23 intervals. Ideally, these lines might be slated at 45 degrees rather like Singapore (or Spain from a lower starting point). This would lead to a genuinely interesting dynamic between the tyres – do you hammer them and chase the undercut, or hold on and go long?

Too often this year, everyone’s choices were kind of forced upon them by the fact that the prime was slower and no more durable than the option. Once the early mistakes had been made and the lessons learned, teams made the right choices and races got a whole lot more dull.