just got me a nice 87 xt600 i plan on just riding her on the dirt around hear are alot of muddy slimmy trails along with soft mountain dirt. some hard stuff but not alot. i was thinking irc m1a and the m5b but ive not seen them on a bike befor or seen anyone run them. also what do you all think about the 140 on the back of the ole xt will it clear. stock is a 4.60 looks to ahve plenty of room but a 140 whew thats alot of rubber. and i am in no way a racer just ridding in some ruff nasty terrain. and some hill climbing.