Ok guys I read all the posts on this thread but didn't really see an answer to my question. I have an '81 Regal and I want to go to a larger rear tire. I want to go to a 275/60/15 M/T ET Street Drag. I have Weld Prostars on there now and I'm wondering what size rim width and backspacing to make them work if they'll work at all. any help will be appreciated as I live in BFIOWA and there is no tire stores around to pick their brains. Thanks again for any help!!