This is really a follow on from jez's Pitstop spreadsheet thread (definitely worth a look if you haven't seen it), but this is going to be a fairly lengthy post with quite a lot of information so I thought this was the best place for it. I got sucked in and have spent many hours since playing with various things relating to strategy and tyre wear, and after today's race I've tried to have a look into the way the Pirellis were degrading. I did something similar for the Monaco race in the original Pitstop spreadsheet thread.
I'm going to try and look at a few other drivers/strategies (more on that later - I need a bit of help) tomorrow, but for now I've looked at the top six (Vettel, Alonso, Webber, Hamilton, Massa and Button) who all used the same three stop strategy (Option - Option - Option - Prime).
In all the graphs below the horizontal axis show the number of laps in the stint, and the vertical axis shows what I'm calling the "Tyre degradation". This is the change in lap time from the start of the stint adjusted to take into account the effect of fuel burning off (0.081s/lap for Valencia according to the James Allen Strategy Report). If the tyre degradation is positive this means the lap times are slower than the first lap of that stint. Also, if a lap time is much slower than expected I don't include it, for example in many cases the first lap or two of a stint have to be disregarded or laps where a mistake has been made.
TOP 6 DRIVERS - 3 STOPS
1st Stint - Soft Tyre
In the first stint of the race the tyre wear seen be all of the top six drivers is remarkably similar, although Hamilton and Massa suffer more than the rest after around lap 10. The averaged graph shows quite a nice clear pattern with the tyre holding up for 8 laps before starting to deteriorate quickly, particularly after lap 11.
2nd Stint - Soft Tyre
The stand out feature for me from this stint is the Red Bulls who manage to go 13/14 laps on the soft tyre without ever being more than 0.5s slower than the first lap of the stint. It may be that other factors are at play - for example, this is the stint where Alonso overtook Webber - but even so it is mighty impressive. The McLaren drivers suffer the worst in this stint, with Hamilton's tyres already almost 1.5s off their initial pace before he pits after just 10 laps. The averaged graph is similar to the first stint, although the tyres seem to start losing pace straight away.
3rd Stint - Soft Tyre
This is pretty horrible viewing for Hamilton fans, frankly when you look at this it's amazing that he managed to finish 4th. In just 7 laps Lewis' tyres have well and truly fallen off a cliff and sunk into tyre hell - during this time his tyres lose almost three tenths/lap performance compared to only around half a tenth/lap for the rest of the top 6. The tyres do stabilise after that though at ~2s off peak performance. The averaged graph is skewed by Hamilton's horrendous wear during this stint, making it more linear.
4th Stint - Medium Tyre
I've included this for completeness but there's not a lot you can take from it. I had to discard a lot of lap times for various reasons, e.g. Webber's gearbox problem and Vettel cruising towards the end. Hopefully I can gather more information on the Medium tyre from some other drivers.
SOFT TYRE - AVERAGE ACROSS ALL STINTS
These graphs are the average of the 3 above. Again, Hamilton has by far the worst tyre wear, although Massa isn't too far behind towards the end of the stint. The prize for the driver that looked after his tyres the most goes to Mark Webber. I am pleasantly surprised by the very smooth pattern that arises when you average all of the top 6 across each soft stint. I used excel to try various lines of best fit and the quadratic shown seems to fit well (i.e. tyre performance drops off seems to be dropping off as the square of the number of laps it has been used for). The coefficient for the squared terms is very small however so the growth is relatively slow. I suspect that beyond 18 laps or so this relationship would caese to be valid and the performance would stabilise, like in Hamilton's 3rd stint.
Well that's it for now. Well done if you made it this far!! I am planning to look at Perez's 1 stop strategy as well as Alguersuari, Kobayashi and Schumacher who did 2 stop strategies, which hopefully will give me some longer runs on the medium tyre to look at. However, to do this I need to know which tyre they were using for each stint. Does anyone have this data or know where I can find it?
Now I need sleeeeeeeeeeep
I'm going to try and look at a few other drivers/strategies (more on that later - I need a bit of help) tomorrow, but for now I've looked at the top six (Vettel, Alonso, Webber, Hamilton, Massa and Button) who all used the same three stop strategy (Option - Option - Option - Prime).
In all the graphs below the horizontal axis show the number of laps in the stint, and the vertical axis shows what I'm calling the "Tyre degradation". This is the change in lap time from the start of the stint adjusted to take into account the effect of fuel burning off (0.081s/lap for Valencia according to the James Allen Strategy Report). If the tyre degradation is positive this means the lap times are slower than the first lap of that stint. Also, if a lap time is much slower than expected I don't include it, for example in many cases the first lap or two of a stint have to be disregarded or laps where a mistake has been made.
TOP 6 DRIVERS - 3 STOPS
1st Stint - Soft Tyre
In the first stint of the race the tyre wear seen be all of the top six drivers is remarkably similar, although Hamilton and Massa suffer more than the rest after around lap 10. The averaged graph shows quite a nice clear pattern with the tyre holding up for 8 laps before starting to deteriorate quickly, particularly after lap 11.
2nd Stint - Soft Tyre
The stand out feature for me from this stint is the Red Bulls who manage to go 13/14 laps on the soft tyre without ever being more than 0.5s slower than the first lap of the stint. It may be that other factors are at play - for example, this is the stint where Alonso overtook Webber - but even so it is mighty impressive. The McLaren drivers suffer the worst in this stint, with Hamilton's tyres already almost 1.5s off their initial pace before he pits after just 10 laps. The averaged graph is similar to the first stint, although the tyres seem to start losing pace straight away.
3rd Stint - Soft Tyre
This is pretty horrible viewing for Hamilton fans, frankly when you look at this it's amazing that he managed to finish 4th. In just 7 laps Lewis' tyres have well and truly fallen off a cliff and sunk into tyre hell - during this time his tyres lose almost three tenths/lap performance compared to only around half a tenth/lap for the rest of the top 6. The tyres do stabilise after that though at ~2s off peak performance. The averaged graph is skewed by Hamilton's horrendous wear during this stint, making it more linear.
4th Stint - Medium Tyre
I've included this for completeness but there's not a lot you can take from it. I had to discard a lot of lap times for various reasons, e.g. Webber's gearbox problem and Vettel cruising towards the end. Hopefully I can gather more information on the Medium tyre from some other drivers.
SOFT TYRE - AVERAGE ACROSS ALL STINTS
These graphs are the average of the 3 above. Again, Hamilton has by far the worst tyre wear, although Massa isn't too far behind towards the end of the stint. The prize for the driver that looked after his tyres the most goes to Mark Webber. I am pleasantly surprised by the very smooth pattern that arises when you average all of the top 6 across each soft stint. I used excel to try various lines of best fit and the quadratic shown seems to fit well (i.e. tyre performance drops off seems to be dropping off as the square of the number of laps it has been used for). The coefficient for the squared terms is very small however so the growth is relatively slow. I suspect that beyond 18 laps or so this relationship would caese to be valid and the performance would stabilise, like in Hamilton's 3rd stint.
Well that's it for now. Well done if you made it this far!! I am planning to look at Perez's 1 stop strategy as well as Alguersuari, Kobayashi and Schumacher who did 2 stop strategies, which hopefully will give me some longer runs on the medium tyre to look at. However, to do this I need to know which tyre they were using for each stint. Does anyone have this data or know where I can find it?
Now I need sleeeeeeeeeeep
. Also, the lap times and tyre information are hard to come by.
. I've got quite a lot of free time over the next couple of months so I'll try and do another race or two at some point - maybe Silverstone and the Nurburgring. Unless I can find away to speed things up I don't think I'll be able to continue it throughout the year but I could upload the spreadsheets etc. I've used so others can try if they want.
