I have over 55K on mine right now. Still going strong tread wise.
Probably could go to 65K if I have too.
My only concern is there seems to be some cracking (like dry rot) between the lugs. Not sure what I can do about that.....
Looking at replacement tires right now.....Goodyear MT/R (Big $$$$$), BFG Mud-Terrains, or Bridgestone Dueler M/T's.
Stone