I just bought new Duratracs which I think will be great in the snow, but I also thought about getting a dedicated winter set for ski duty coming up soon. I found a set of brand new Cooper Discoverer M + S that allegedly came off a Land Cruiser on CL for cheap, but they're in a pretty small size: 255/55/18. I have some extra LC rims in 18" with no tires mounted currently, so I thought about picking these up and rotating between the two sets for ski trips. My question is though is are they too "small" to run? The overal diameter is calculated to be only 29" and right now I'm running 32.8" diameter, so I'm guessing my speedo would then be off in the other direction and rpms would be fairly high. Perhaps maybe I'd get a little better mpg with the lower weight/rolling resistance but it could be negated by the higher rpms. I dunno is it worth it to give it a shot?