Originally Posted by Ed Holland

jcwitte - could the sensation be described more as a vibration or buzz than a grind? I have noticed this with new stuff, sometimes after chain cleaning too, and always in the higher gears as you describe. It is -I believe - simply a resonance in the chain. The top portion of chain is under tension, like a musical instrument string and is "plucked" each time a link is released from the rear sprocket, a process that can never be completely smooth because the chain is comprised of descrete segments.

Perhaps this offers an explanation?

Cheers,

Ed