I replaced my stock Conticraps about 10K miles ago with Michelin LTX M/S-2's on my factory 18" rims. Love the new tires in every way. With the 70K mile guarantee, you can't go wrong. My F-in-L got the ATs on his 2012 SD and I swear they're already at 50% and he doesn't tow anything. I've never had them, but I'm not so sure they'll hold up very well with a heavy 5th wheel.