Had first blowout

x2 on Rock's comment about Valves! Our previous owners had good tires (Bridgestone Duravis) installed by a local dealer. They used the "high pressure" rubber/brass stems. Then the owners put goofy little screw-on extensions on them. If I did something that twisted the rubber valves, or cocked them to an angle, I could hear air escaping. We have simulators and the rear duals were an emotional experience to check. Worse to add air and I had to do that often. Went to solid brass custom stems and air-through caps. I now can check six tires about as fast as I can move between wheel positions and they rarely need air.
We just had another inner right dual blowout thread. In this case, he knew the tire was going down.