^Definitely, the same as everyone else does, and this doesn't change with his strength levels. He doesn't stay either hot or cold for a different amount amount of time as his strength depletes, either. There's always the risk of him being more careless and burning through more tire when he's at max temp, but this has gotten less risky as his level has increased. I look forward to watching him drive for 24 hours straight. I hear race car drivers lose about 1 pound from sweat alone during an hour of driving.
I hope this doesn't get patched soon...
Is your driver having to fight for position at all once tired in these races? I definitely notice an increased likelihood of mistakes from tired drivers battling for position. They can overtake lapped cars that are pulling over for them just fine, but they will be making too many mistakes to keep a position or gain a position if they have to fight for it. When they're just cruising around it doesn't seem to matter at all like you said though. As for the lap times, the car is lighter so it should be faster late in those enduros. Getting a clear lap to run fast is the real challenge at that point.