I'm using RPM wheels with my stock SS hexes and they work fine. You just have to remember to tighten those wheel nuts down after every tank. If you don't have the $$ for new wheels, you can buy aftermarket hexes by GPM, Hot Bodies, etc, all of which I heard work better than the stock hexes. If you buy larger wheels like those Dozers you have to worry about steering issues, IE you have to run a 6V hump pack, possibly a stronger steering servo. Not to mention that it is a little more stress on the drivetrain, which goes into gearing changes, etc.....