Spec C 12.5@110 (345/355)
how do you mean the tyre sim doesn't affect ai?
just because you read it on those forums? as if the ai always have tyre sim on (as these are your settings you are choosing, not theirs) then you aren't going to notice any difference in their times when you turn it on, as its only affecting you by making it the same as them by taking away your advantage. if it makes you place properly then why not turn it on, it works, its harder with it on, you need to warm the tyres up first and you need to watch out when you go off the track and collect debris.
I really am not sure why people keep saying tyre sim is faulty apart from having read it by some yank moaners on the CM forum.
I've seen it happening on all my <100% races with tyre and fuel on. The main thing that shows it is getting off the line, you have 100% fuel and cold tyres the AI don't and you get raped off the line, everytime. Turn it off and you can get off the line comparatively with other cars around you.