Hey guys. The devs will have the only answer to this but I feel there is a massive flaw behind the tyre temperature system.
Giving it some thought and comparing to the real life racing. I feel that tyr etemps do not lose temperature gain overtime while heating tyres.
Lets say the tyres start at 0C and at push 5, they gain 10C every sector. Now the way this works at the moment, is that if the car remained at Push 5 for 10 laps, the tyres will be 300C, not including the tyres wear to the temp cap it effects.
Now in real life, the gain of temperature should reduce per C it gains so after about 50C that 3C should be reduced to like 2C and not remain constant and judging on what I see in the simulator, I feel this is not taken into account. So at the moment, tyre temperatures seem to have a static increase and decrease and not effected by the tyre's current temperature.