Old 05-22-20, 06:10 PM
cudak888's Avatar
Join Date: Sep 2005
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No pictures for this (and the cable did not arrive today), but I think I've figured out the front derailer issue: The KMC 8.1 chain is incompatible with the ramping on the Rotor chainrings.

I put a different BB on the bike today (unfortunately, too wide), but that had the odd side effect of making the front derailer/chain interference extremely violent. After examining the interaction between the chain and the pinned ramps, it appears as if the Rotor chainring catches the KMC 8.1 a bit too well, sending the subsequent links onto the teeth before they've even cleared the front derailer.

I replaced the KMC chain with the Dura-Ace 9-speed set that came with the derailers, and the problem instantly vanished. So that's one additional issue taken care of - and I didn't even have to shim the FD to do it.

Incidentally, if anyone has a 68x113 Shimano UN55 bottom bracket they'd like to get rid of, I'm listening.


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