No, I really doubt it. Grinding popping and tire chirping. Or mean howling and occasional horrible clunk would be ring and pinion.
Sounds like typical tire woes to me. The carcass of the tire is made of polyester fabric, and there has to be an overlap for strength. Add a whole bunch of rubber (weight) and this can make not just a heavy spot, but a harder spot. All tires as far as I know are built this way, and sometimes it makes a wobble that is very similar to out of balance. Rotate your tires, and it likely will go away. When you rotate them back, it likely will stay gone. This sort of thing is just the way tires are.
Could be a bad shock, or something loose, too. Might be worth a peek underneath.