Title says it all.

when rolling in reverse (irrespective of the tranny/cluth), my car will often let out a weird "moaning" vibration, seemingly from the passenger side. having the steering wheel to the left while reversing seems to exacerbate this. wheel bearings/front end seem tight. car drives super tight.

i'm all ears.

inadequate venting clearance on the rightside caliper?
wheel bearing (less likely ...) ?

So, you can hear the noise while rolling backwards in neutral, correct?

Does applying brakes cause the noise to change or stop?