Doo you have a dually?
A cpl yrs ago I sheared a wheel stud and the nut and part of the stud were rolling around inside the hubcap. Only heard it at <10mph.
Then just this spring I had another issue. It would make funny noises - that sound like "hubcap" noises - comming from same wheel (front drivers) around 45mph. I start hitting brakes at diff speeds, cranking the wheels off in each direction, (Be carefull there is no oncomming traffic nor cops in sight - it may be hard to talk your way out of?) nialing the throttle, everything. Seemed to be simply speed oriented. 40-50mph. ???
After my experience a cpl yrs ago - I fingered that maybe I snapped another stud - but this time it was one of the four that were stuck in thecenter cap ... and the centri-force of 45 mph was enough to make funny noises. ???
Yanked off the cap and found nothing. ????
Reassembled. Next trip out - aboot 45 mph I get the funny sound. Now I know that it is the cap - somehow as it is a tinny sound and I couldn't affect it in any other means before.
Next time I yanked off both caps and no noises. Then I would install one w/o the other. (inner/outer) No noises... . Reassmble - noise. :-{}
It seemed that the two were rubbing together at speed.

Took the one pound dead blow to the inside of the "outer" at any points that looked to be "compromising" ... . I haven't heard it since. Oo.