I had an 87 hardtop GN that was stolen years ago. I replaced it with an 87 GN with t-tops. I had a set of rims that didn't get stolen with the car[running stockers when it was stolen] . A few years later I replaced the tires with the same size tires and had to put spacers on the rear so I wouldn't rub on the t-top car. Somebody told me the frames on t-top cars were a 1/2 in. narrower. Any truth to this or could the variation be in the tire manufacturer. Seems like 255/50/16 is always going to be 255/50/16.