I did the usual wheel bearing check. Grab wheel at 12 & 6 - shake. Grab wheel at 9 & 3 - shake. It feels good, no play. When I rotate the wheel forward and change direction to reverse, I hear a tap. When I take off the caliper, the tap is gone, but the hub feels a little, uh, lumpy?
Since the sound goes away when I put pressure on the brakes or remove the caliper, I'm thinking it might be a loose pad. It's a very faint tap tap tap that increases with speed.
And yes, the same hub is used on all four wheels, with ABS. Looks like they're around $180 on Rock Auto.
The tires and wheels are new, direct from Tire Rack. I didn't notice anything abnormal. But, I DID start to notice the sound when I put the new wheels and tires on. Strange things are afoot at the Circle K.