Thanks for the excellent explanation.
Since we installed two entirely new rotors and pads in the rear,
our occasional "whoosh-whoosh-whoosh" sound coming from those wheels wouldn't be a run-out issue, I gather.
But if the "bench fixture" is possibly bent or not parallel with the resting part of the rotor,
I wonder if that could be enough to have the rotor and pads still making contact.
We *ahem* did whack on that one rear rotor behind it by jamming a big screwdriver between the rotor and the housing,
and slammed on it for a day and a half (thinking rust had cemented it) until we realized the emergency brake release wasn't ... released.
Then it came right off. Yes, we were idiots.
Things looked fine, except for the thin ... what do you call it vertical round thin pan that the rotor is housed in,
that was a bit bent in spots. Now that I think of it, there was a fresh wear spot on the inside of that when we initially pulled the rotor off. So even before the whacking we did, it was rubbing in there.
So the original problem caused that, and new rotors didn't solve it.
Could the entire rear axle maybe be slightly bent or misaligned?
Wonder if alignments are covered under warranty.
I do ride it on my mile long rough mountain road daily.