Your tire will apparently change 0.2" in height for every 0.5" of rim width. So 255 on 8.0 will be 0.2" taller than 255 on 8.5, probably not enough to shrink the gap you are trying to fill.
Having said that, 255 is apparently the maximum size for 8.5" rim and too big for 8.0" anyway.
http://www.pneus-online.co.uk/equiva...es-advice.html
Although 255 on 8.5 seems to look ok?
http://www.e90post.com/forums/showpo...&postcount=110
