Is that the tire size you meant to post? If it is, there should be no problem fitting them. Your speedo will read a little fast, but you will have a little extra power, without too much of a mpg decrease.
Ah yeah I meant to tell you, I was dead set on the Dunlop Maxx Tractions but when I ordered them from discount tire direct they were out of stock and it was gonna be 3 weeks for a new delivery. They said that model of tire just went crazy popular. Anyway I just got my 255/85's KM2's today and im gonna get them mounted tomorrow. Sucks as i wanted 285's bad but that will have to wait next go around, and if i like the 255's i hope they make the Dunlops in that size, we shall see.