hear back from john. he's gonna take a look at his clearance between the sidewall and UCA. he's running the same wheels and UCAs as me, with 2'' spacers, and 315 treadwrights.
as the treadwrights generally run large compared to other tires in the same size (due to their construction), i figure that if he's got 0.5''-0.75'' clearance or more, i should be ok.
0.5'' and less will be bad news most likely.