i had mine on from 1993-1999,did a lot of lake ontario trips in that time,over 300 miles round trip,and also around my area,lots of back roads,a few dirt,not many.they still had thread on them,wore even also.the only reason i replaced them was 1 tire got a broken cord in it,and the thread was starting to bubble out.i still have the good tire yet.
i switched to bridgestone radials,what a diffrence in towing and ride for the tow vehicle also.the radials on the trailer are the best investment i made!