I've got 2000 miles on my 450i. not much for recreational use, many higher speed (40+) on road, sometimes towing 1000lb backhoe, also dragged I don't know how many cords of firewood from the stump to landing, some dragged tree length, some in sled, right now I'm waiting for a couple of ball joints and a half shaft.
my top speed has dropped from 49, to 46. but no detectable slippage in belt,even when getting heavy loads moving