8 or 8.5" has to do with the width of the tire, not height. Do a quick search on rims and tires and you will find all the info you need. The Z can accomodate up to 9.5" width in the rear and 9" in the front without and modification or lip rolling. There is an excel spreadsheet available that shows what tire sizes and rim sizes work with the Z. Try a search to find it. If not, e-mail me and i will send it to you. -TTony