Since these were trailer tires that you brought in off the trailer the air pressure we used was the manufacture recommended minumim pressure. it appears that you decided this was not enough so you increased it. OVER inflation is the reason the tires wore out. we had no way of knowing what you were hauling or what the weight was so we did not over inflate . Next time check you weight and then determine correct air pressure. by the way we don`t work on lawnmowers.