With 5.5, you should be able to run a 33 on an 8" rim with some rubbing and maybe minor trimming. I'v never heard of 8.5 inch lift..unless your planning on doing a 5.5" lift and then a 3" body lift. I think if you do that you can run a 35 on an 8" rim with some minor rubbing and minor trimming. I've never done any of this but this is just what I'v read on this site.