Solved

Tyres

Can someone tell me the cliffs of each different tyres?

It will depend allot on each track you race at, weather temps and ware rate for that track. 
In saying that most managers will say once your Tire gets below 50% it will start to lose speed. I will run my tires 30% and still get fair lap times out of them, Under 30% and you start losing big time on your lap times

Thanks!