BFG lists 6.5"-8.5" wheel width for mounting so should work good for on-road use. For off-road use, it may not air down as well and the tire will not offer as much wheel/bead protection as it would on a narrower rim. I run mine on 6" rims and they work well, a 10.50 works even better on 6" though:
http://www.4crawler.com/4x4/BFG_AT_KO.shtml