...hier die offiziellen Angaben seitens AC Devs zu den Reifen - viell hilft es Dir:
http://www.assettocorsa.net/forum/index.php? threads/tyre-temperatures-and-wear.2723/

Road legal tyres
Street and semislicks are road legal compounds, used on the road. They wear out slightly. Their main problem is overheating, but after you have overheat them you can wait and start again, they can give similar grip even after lots of km's. In the end they will wear and lose grip totally.
Street tyres optimum temp: 75°C - 85°C but "easy" under and over those temps. Very easy to overheat after some laps on a circuit, especially on fast corners.

Semislicks: 75°C - 100°C but a bit less grip under that and overheat quite faster over that. They have more grip of course and can resist more fast laps, but do not like much abuse and drifting. They wear gradually and lose grip km after km.

GT2 slicks
The main difference of the GT2 cars is that manufacturers are actively developing tyres during the season and bring different compounds on the various tracks. We can't of course simulate specific compounds for specific tracks, but we offer 5 different compounds

SuperSoft: 90-105°C Don't like to be driven under or over that range. They wear out very fast

Soft : 90-105°C as Supersofts. they wear out fast

Medium: 85°C-105°C as supersofts over their range. They wear out in a linear gradual way

Hard: 80-100°C a tiny bit easier than supersoft outside their range but nothing too radical. They wear just a tiny bit after the initial laps and then stay quite stable for a long time until they start to lose lot's of grip

SuperHard: 80-100°C as Hards. They wear a tiny bit and stay stable for lot's of laps until they let go.

GT3 slicks
The biggest difference between GT2 and GT3 cars are their tyres. GT3 tyres are fixed for the whole season and the organization decides what tyres the car have to use. We provide 3 compounds that are not equivalent to their GT2 counterparts (worse).

Softs: 80-110°C . Wear VERY fast. We've been told that they were actually used only for a couple of times in qualifying.

Mediums: 75-105°C Wear linearly and predictably. all around tyre

Hard: 70-100°C Wear a tiny bit after a couple of laps and stay stable for a long sting. Not great grip but they are predictable and can be used in a wide variety of tracks and temperatures. Often "forced" by regulations on cars.

The hypercars slicks (Zonda R and 599XX) are a bit worse parents of the GT3 tyres. Let's say a generation behind. Rest of their characteristics is very similar to the GT3 tyres.

Vintage F1 67 Tyres
We provide just one compound for such tyres, although we learned there were actually different compounds. As a matter of fact, there is documentation reporting that Jim Clark choose the tyre that permit him to slide more for the race at Monza. Unfortunately there is not enough documentation for the compounds so for now we stick with just one compound. If anybody has more info regarding the matter, I'd be happy to discuss with it. optimum range 50-90°C The tyres are good at low temps, and can withstand overheating pretty well. The tyre wear is gradual, you can expect to do a full race without problems, except if you overdrive and overheat them too much.

The tyre ranges are not perfect ranges but a min max range that you might not be able to understand a difference in tyre grip. Temperatures are also vary quite widely from straight to inside a turn, so optimally you need a tyre that stays at the lower end of the optimum temperature just before the braking zone and at the higher end of the optimum temperature at the exit of the turn. Not so easy to obtain.
In AC going outside the optimum range, doesn't mean the car will become undriveable. This characteristic is a double sword. You might think the car is good, but you're not driving on the optimum grip, so you'll lose time without understanding it. There's depth to be found and explored within the AC tyre model.

Another hint for tyre temperatures, as in real life, use more camber to heat faster a part of the tyre tread and then this dissipate to the rest of the tyre. More camber, more heat, less camber, less heat.

Hope you find it interesting."