I'm running Dynapro AT-Ms on my Ranger and really like them, but they are LT-rated, 10-ply and heavy -- great for offroad but not great for mpgs. The 255/60R18 Dynapro AT-Ms shown on Tire Rack are P-series (not LT) and weigh just 5 lbs more than the RL's stock Firestones. Tire Rack says to check the specs for AT-M sizes that don't get the deep snow rating, but I couldn't find that info for the P255/60R18s.