Last race (Austrian GP) I was lucky enough to watch the race from Williams’ factory as part of their “Race Day Experience”, which I highly recommend. The race was projected onto 3 screens. Sky F1’s feed, track positions feed and live timing. I used to religiously have the live timing up on a laptop whilst the races were on, but I stopped a couple years ago because I felt it distracted from the action too much – which applied again for that day.
I found myself not watching the race through the world feed, but through the numbers on the live timing again. I spotted that Hamilton would lose ground to Rosberg at the start of stints and gain towards the end as shown on the graph, suggesting that his setup/driving style traded pace for lower tyre degradation. This was especially clear in the second stint and emphasised by the fact Nico’s brakes were critical during the final 2-3 laps.
I remember turning and saying to my Dad, who was with me at Williams, “Hamilton should stay out for another 5-6 laps”. It was clear he was able to save his tyres better and was still lapping in the mid 12’s. If you can pit much later then your pace difference will increase more as the tyre degradation curves accelerate and it would give Lewis a greater speed advantage he needed to stand a chance of overtaking his teammate.
Its the opposite to the undercut. When you pit later, lose time whilst your opponent runs with the new tyre, but gain slowly over the stint with a large tyre performance difference. The more laps you wait, the more you’ll be behind coming out of the pits, but you’ll catch the driver ahead at a greater rate. Its about balancing the two.
In any normal situation, you’d prefer to undercut, but with Mercedes prioritising the driver ahead its the only choice Lewis had.
I’ve calibrated my “Laptime Simulator” spreadsheet to represent the times of the two Mercedes drivers to the best possible fit. Let’s find out, in hindsight, whether it was worth a shot or not:
(Remember the first 6 laps were behind safety car) And when we compare the two side by side, the difference is evident:
Rosberg is the blue. Hamilton is the orange.
Both pit on the laps they did in the race. Tyre degradation still accounts for an early safety car.
Laptimes are comprised of the one-lap pace multiplied by a race factor which accounts for the race settings / driving styles, and the cost of fuel and tyre degradation which were marginally different for the teammates as shown here:
This shows if the prime tyre was used from laps 1-35 of the race, hence the heavy fuel cost
Now the interesting bit. We simulate the race when Rosberg still pits on lap 33, but when Lewis pits later. We continue Hamilton’s laptimes on the supersoft tyre using the same degradation and play out different scenarios:
Pitting on lap 42, Hamilton comes out of the pits 14 seconds behind Nico and 8 seconds ahead of Felipe Massa in 3rd. His first lap out of the pits is also slower than Nico by 0.1s, but he gains 14.4 seconds on Nico over the next 27 laps…
Let’s assume Hamilton doesn’t cross the pit-lane exit line and pick up a time penalty. If the cars could phase through one another, Lewis wins the race if he pits on lap 42 by 0.3 seconds. The supersoft tyres lasting 42 laps as opposed to 35 is realistic, and he did not need to cover Vettel as his pitstop was slow. It was definitely worth a try. Too late to do anything about it now, but for future races this is something to consider for either two drivers if their tyres will last.
Hamilton catching Nico with a lap remaining would’ve been a tantalizing finish to the grand prix, maybe just a bit nerve-racking for the pit wall. The pace difference at the end of this scenario is over a second a lap. Whether this would be enough to pass an identically-powered car in 2015 I don’t know. Considering that he catches towards the end of the lap… I’d guess not.
