I'm running 5.5" bs, and like I said it rubs sometimes, so if you want to try to run more then 5.5" bs, best of luck to you. I have about 1/2" between the tire and outer wheelhouse, all stock, non modified. I'm very skeptical about that 6.25" bs. On my car you'd be replacing tires really soon, if it got out of the driveway.