1995 E320 Cabriolet at the right rear wheel makes a noise that changes pitch with the speed of the car, but doesn't change sound as you load or unload that side going around curves like a wheel bearing would do. Kind high, metallic sound. If you've ever had a car with wire wheel covers and the spokes were loose, it kinda sounds like that. Or sorta like a lug nut that fell off into the hubcap but not so loud. Took the wheel off and spun the axle by hand but couldn't duplicate the noise, just a little normal rumble or scrape from the pads. The dust shield isn't touching any moving parts either. Any other ideas? Could it still be a wheel bearing?