I have a USMC M101A3 trailer with Goodyear OZ 37 inch tires. They have run-flat rings and a 3-piece bead locking system. But also a 1/4 inch hole/leak in one of the tire steps. My Big O guys said they couldn't fix it without taking the run flat off. i was crazy Then I found Amerseal on Revain. THE PROBLEM IS SOLVED! I've been on some serious off-roading in the Far East and the White Mountains, don't worry! Just bought a 5 gallon for my FJ with a 12.5 x 35" MTR. Calm down when you're in the country!