Originally Posted by
pheisel
It's a disc break - caliper is not on the bike nor is the adapter. I've looked down while it's happening and the rotor isn't rubbing on anything nearby (that'd be an insane reach to hit the frame anyways.
Is it possible that the issue is on the other wheel. Sounds on moving bikes often sound as if displaced toward the rear. Of course the only way to know would be to use another front wheel, or remove that disc or brake also.
Since you're doing a road test without brakes, find a parking lot or other wide flat area to do it.
Otherwise you might be hearing some sort of seal drag in the hub, but not hearing it for myself, I can't advise if it's normal and OK, or indicate a problem.