Tyre Temps / Management

Hello Guys, I know that iRacing is very unique in its tyre model etc., but can someone explain to me, how much you can use the tyres in one corner, so that it doesnt make the next corner slower. I know this is very poorly explained (not my native language), but for example, when i dont push in one corner, then im suddenly 3 tenths faster in the next corner without doing anything different compared to the previous lap.