The 1st broke while I had the passenger tire on a ledge. I was barely moving and it snapped. no tire spinning, that is not my style. The second break I have no idea. Didn't know it was broke till I got to camp and on the pavement I didn't hear the aussie clicking. That is when I noticed the hub. There was a spot where I was hung up, and had some spinning tires, probably happened then. Not sure. I ran every trail in Uwharrie, burned almost 1.5 tanks of gas. I would say I was "hard" wheeling. Definitely more than anything I did in Moab last year.