yeah - the bang was the Alcoa hub over the dually falling off. It apparently can come loose. Just to clarify -
1. the tire went from 100lbs to 70lbs - drove that way for awhile, then at the next rest stop refilled it to 100lbs.
2. it stayed at 100lbs for weeks afterwards. I also had the jacks down so the weight of the rig was not on the tires when they finally did go flat.
3. Had the tires inspected - they looked great. The nail had hardly punctured the tread. That is probably way it took a few weeks to actually deflate.
I am not going to take crazy risks - my family rides in that thing with me.