I agree with dillonjm...check balljoints...hell even check hub bearings. typically outside tire wear on cases I've seen is improper alignment, usually toe. judging by the Ujoint comment, this wouldn't seem too far fetched.
you can check toe real easy with a buddy. essentially measuring track width. go by the seem on each tire with a tape measure as high as you can on the back (control arms will limit you) and equally as high on the front. Difference should be about 1/8" with the front measurement being less.
2" BB, 33" KM2's, front stinger, rear exogate tailgate, skids, Uniden CB radio