India in Depth: Seeing the low degradation

Posted on November 6, 2011


In trying to get a better impression of the low degradation in the Indian Grand Prix, I have made myself a new toy using the fuel effect component of the intelligentF1 model – the fuel corrected race history chart. I have done these charts for India, where the degradation was low, and for Japan where the degradation was high, in order to leave the tyre degradation as the major effect on the pace of the cars through a stint. What becomes obvious is that the longer the stint, the clearer the tyre degradation effect becomes.

The Indian Grand Prix chart is shown below for the leading cars.

If the fuel effect model is correct, then the gradients of the lines should be the same in each stint on the same tyres, and the difference in the pace between the tyre types can be seen from the difference in the gradients. The gradient match between the first and second stints is very good across the cars (except for the first few laps – rubbering in of a new track perhaps?), and it becomes easy to see that Hamilton is faster in the second stint than he was in the first. Also of note is the greater curve in Webber’s trace – he is seeing more degradation than the others. Vettel looks like he is struggling at the end of the second stint as well. The hard tyre is conclusively slower in the last stint, and the McLaren is obviously slower on it relative to the Red Bull. The other thing to note is the straightness of the lines – the lack of curvature indicates low tyre wear.

In contrast, here is the fuel corrected chart from the Japanese Grand Prix.

The effect is not quite as easy to see here as the stints are shorter, but the difference in the traces of Button and Alonso in the third stint show that Briton is experiencing more degradation than the Spaniard. All the traces of all the cars turn over before the pitstops, which shows something of how the teams decide when to stop. On the evidence here, the teams look for signs of the tyres going, which (you would expect) tallies with the information from the driver before stopping. In India, there is less sign of this – and no sign of it in Button’s trace. One more thing – whilst most of the gradients are consistent from stint to stint on the soft tyres, there is a very clear drop in the fuel-corrected pace of Hamilton and (especially) Vettel between the first and second stints – this has to be to prolong the life of the tyres. Vettel is slower again in the third stint – which suggests he used his new tyres in the second stint.

I intend to use this new toy to improve the intelligentF1 model fits in the upcoming races, which should provide an even better insight into what really happened.