Solved

Tyre question

If you review your race results you will see that for example a 10% tyre degradation doesn't mean that after 10 laps the tyres would have worn to zero.

Wear is subtracted from the remaining tyre life. So for a 10% wear rate the APPROXIMATE tyre life will be:

End of lap 1: 100% x 0.9 = 90%
End of lap 2: 90% x 0.9 = 81%
End of lap 3: 81% x 0.9 = 73%
End of lap 4: 73% x 0.9 = 66%
End of lap 5: 66% x 0.9 = 60%
End of lap 6: 60% x 0.9 = 54%
End of lap 7: 54% x 0.9 = 49%
End of lap 8: 49% x 0.9 = 44%
End of lap 9: 44% x 0.9 = 40%
End of lap 10: 40% x 0.9 = 36%

Well, that's theoretical ground because mathematically you can't reach a tyre condition of 0%. Even at 15% wear per lap it takes a little bit more than 28 laps to drop below 1%, but that's already about 14 laps below 10% tyre condition and thus with a chance of puncture, so I'd guess a car wouldn't even make it that far. Haven't worn down a tyre into puncture ground ever though, as the lap times suffer extremly way earlier.