Who would have guessed ??....... I have seen bulges in many car tires also. BUT they where all from beads being forced on at install cutting bead wall and letting air get between bead and sidewalls. So yes it can happen to car tires also if not installed properly. I killed my second run flat while spooning it on and throw away a new tire because I did not know when to stop prying monster stiff sidewalls over rim 4: and I am strong like gorilla when angry,sweaty, and bullheadedness takes hold of my crowded brain. :nojoke:. too many cookies.