Buzzing/vibe in big ring, small cog(s)
OK, I got a north american hand-made bike with an annoying issue.
In the big ring, there's this buzz/vibe coming from the rear of the bike, chain/deraileur/cassette interface. No amount of tuning cable tension or adjusting high limit screw seems to get rid of it. Nothing seems to be rubbing, either.
Spec'd with 2010-ish Ultegra drivetrain, traditional road chainrings, 11-23 10sp cass. Came built with Fulcrum 7 wheels, shimano freehub. Also tried Bontrager SSR Aero wheel with different freehub, lower level cassette with wider range, still the same issue on the big/small combo.
Frame alignment appears to be within tolerance -- when I check it out with the ***-2, NDS measures 1.25mm space compared to flush on DS. Not spot-on, but seems not too far out, not enough to cause buzzing issue.
Seems to be an alignment issue between the chainrings and cassette, they are not aligned, but crank is outboard bearing crank with no lateral adjustment possible. Checked it out with a different wheel/cassette to see if that would put the cassette more inboard, but no dice.
Anyone encountered similar? Possible fixes? I'm stumped...
I know next to nothing. I am frequently wrong.