I put all season radial size 225/60R16 on my car back tire on driver's side rub's on bottom of strut.

Has the vehicle been in any accidents on that particular corner of the vehicle may possible have a bent rear strut? Do you know if the rear camber is out of manufacturer spec Does the tire look like it leans in to far? GM did not provide a rear camber adjustment for this vehicle but cam bolts are available to correct some of this adjustment another option is elongating the one of the holes in the strut where the lower strut bolt attachs to the knuckle to provide adjustment. Would take this and have an alignment performed to see if if the rear adjustment can be corrected with suggested methods.