I run 275 up front and 285 in the rear and I get a slight rub on the plastic liner. I don't feel it and it does not degrade the tire but I noticed the rub spot. The rears are fine.
I run 315's in back and I rub on something alittle on funny angled turns that go uphill. other than that there fine with a quad shock flip (going to remove when I install the ssm lift bars). So you should be fine with 275's.
I don't have any rubbing going on and the only time mine rode roughly was when I had the KYB's and B springs. But it was much smoother than it was on the 245's on the stock Tribars that I had before. Now with the Cobra Bilsteins and C springs, it's pretty smooth. Now, I just have to get those X2 balljoints in that I have sitting around. Ride should get better then.