MuuMuu101's 68 Dart, A Learning Process...

It'll work with 275's. Keep in mind that you won't see the same section width's because you're putting the 275's on a 9" wide rim, they're measured on a 9.5" wide rim. They'll probably only end up being about 10.6" wide on a 9" wide rim, that's about what my 275/35/18's measure on the front of my car. Based on your pictures I'd want most of that extra width on the spring side though, I see what the tape says but I don't think I'd want to give up too much more clearance to the quarter. I only run about 3/8" to the springs with my 295/35/18's on 18x10's on the back of my car, but I've never had an issue with the tires rubbing the springs.