I recently bought a used AC350 Sprint wheel set, in the interest of trying a light wheel set in lieu of my trusty (but heavy) Mavic Cosmic Elites. The wheels are definitely lighter, and have been nice to ride, with the exception of a noise I cant get rid of or identify in the front wheel. It's hard to describe, but it's most like a rubbing/grinding sound. On smooth pavement I don't typically hear it, but on rougher surfaces it starts up. Also, it's somewhat intermittent, so that it's not a constant noise throughout the entire wheel revolution. I can't say that it's at all consistent though. My first thought was bearings, so I replaced all the bearings in both wheels (2 front, 4 rear). No change in noise. I've also tried adjusting the bearing pressure, to no avail. And before someone asks, there is NO contact between the pads and rim surface, and the wheels are true. Also, the front wheel will spin all day when theres no load on it (in the work stand). At this point, my thought is that it may be an issue with spoke tension that is somehow transferring through the rims. Being that they ar fairly light rims, maybe it amplifies the sound more or something? I know I'm grasping at straws here, but I'm out of ideas.

Anyone have a suggestion or experience this?