I got 255/60/15 at all 4's on my 71 Cuda,...that's maxed out on 15X7 rallyes for a Cuda, at full turn the tires "just" start to rub on the frame, the Cuda has a little less clearance than the Challenger in the rear, I tried fitting my Challenger's 275 on the rear, no-way,....... on my Challenger 255/60/15 on the front, and 275/60/15, all Goodyear Eagle GT II's,....check your tire choice amongst other manufacturers, GoodYears of the same size as BFG tend to run slightly larger in thread with, or cross section width