Best I can describe is something between a clicking and rubbing. It's low freq. Again, it don't do it for about the first 30 mi. Then becomes noticeable as your stopping. Can't feel it, but can hear it (slight noise) in the car. Wife says she can't hear it outside as I roll by. The more you drive it gets to where you can hear it as your traveling 60 mph. It's definitely rotary, and worsens as things heat up. Crazy question - Can tires be expanding as they heat up and causing a rub? I've raised the front end, spun the tires, nothing loose, no noise, slight brake drag (as normal)