mconlonx

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...

mconlonx

Aligned derailleur hanger, torqued lock ring on cassette, flipped the chain over. Something helped, but buzz/vibes still apparent.

What am I missing...?

skilsaw

Are the jockey wheels on the rear derailleur rotating freely?

mconlonx

Yep. Top one also has side to side free play like it should...

bikernew

did you ever get this figured out??? i myself seem to have developed same type of noise, and think it is my RD cage alignment but trying to fine tune my tension(indexing) doesnt help. I've heard it on other bikes going past me and thought it was 'normal' and that my bike was just breaking in. i probably now have 4-500 miles.

cny-bikeman

Well, almost 4 years later one would hope he found a fix.

Do a forum search for chordal action - may be what you are experiencing.