In my case the only time I have had a flat was 3 times in 4 months and it was not the duals, it was the left front tire.
And the bead busted every time without being moved.
The first time was in front of our home and we were just ready to leave. The next two times I found it flat in the storage yard.
The shop that finally fixed it found that it had a very slow leaking valve and the guy that came out and fixed it the first time told me he replaced it.
The last time the shop took it all apart, cleaned the bead surface and put sealer on it after replacing the damaged slow leaking valve.