One day my Uncle John was towing one of them back to grandpa's shop. He had just noticed a vibration when his pickup ground to a halt. A wheel bearing had gone bad and a tire came off the axle of the welder. This made the machine drop to one side and act as an anchor, which stopped the truck quickly and suddenly. Uncle John looked in the rear view mirror, helplessly watching the disconnected tire bounce across 4 lanes of traffic until it slammed against a parked car, severely damaging it. He knew he would have to go find the owner and do what he could to get the guy's car fixed.
About then the owner ran from his house waving his arms and vigorously exercising his vocal cords, obviously and understandably upset at the incident. But all my Uncle could think was, "You picked a fine time to leave me loose wheel."