275/60r15 firestone indy 500 on the rear of my 69 camaro. I have crager 15x8 w/ 4.5 inches of b/s. they fit. I do get a little rub when i get on a steep incline (my driveway) on the ineer fender, but that is it. So everyone knows the 275 is the width (275mm wide), the 60 is the aspect ration (60% tall as wide) this will never change, so one 275 is no wider than anyother. The footprint of the tire may change from tire brand to tire brand, but it is still a 275mm wide tire. I am going to switch mine to a 255/60/15 just to see if it looks better,I manage a tire shop so I have nothing to loose
69 x-11..LS1, 420.88 horse to the tires,750 Holley Ultra DP, Torquer V2, darksides headers, PRC heads, 10.8:1 compression, forged bottom end, 5 speed. 2008 King Ranch F150 4x4.