Originally Posted by persian54
Would you say a 285/30/18 is too short of a tire? I say this because, as you said "depending on availability," the AD08s don't come in 285/35/18.
Would 295/30/18 AD08 clear (no rubbing anywhere) with a 10.5 low offset?
The square set up you mentioned is a great set up.
Correct, 285/30/18 is shorter than ideal, and can prove to be better or worse in it's gearing change. For someone doing a regular HPDE, it may have no consequences beside a slight change in shift points, and that would depend entirely on the track as to whether it's a positive or negative change. At the 25 hours of Thunderhill there was an E9X M3 with 285/30/18 square on 10's for example.
So if all you can get is a 285/30/18 in the compound you want, then don't let it stop you, unless the front tire size you're going to run is unusually taller, such as a 275/35/18 up front paired with that size rear. Then you'd have a reverse rake, for a car that normally has a noticeably taller rear.