Should be fine with a steel wheel or rally wheel. They were fitted to Formula S cars from the factory with 14 x 5.5 steel wheels.
I was just test fitting a 14 x 7 SBP Torquethrust. It looked like it would clear the rim fine, but it needed the center hole machined out deeper. It was 2-5/16 dia., all right, but the cut wasn't deep enough to go all the way down -- it stuck, leaving a 1/4 inch gap to the hub face. I suppose this is why these wheels came with a set of 1/4" wheel spacers. But that adds to the offset, which is already more than desirable (backspace is only 3.5", should be more like 4"). Anyway, that's besides the point...