[CR]regina chain skip

Example: Events:Cirque du Cyclisme

From: "Decruyenaere, Joseph" <jdecruyenaere@planning.co.la.ca.us>
To: "'classicrendezvous@bikelist.org'" <classicrendezvous@bikelist.org>
Date: Mon, 24 Oct 2005 08:40:11 -0700
Subject: [CR]regina chain skip

Hi group,

Some drivetrain/transmission questions for the COG-noscenti. HAR HAR HAR! Sorry...ahem...

I recently acquired a lovely DeRosa, ca. 1979-82 (it's got those Campy chain-hanger holes in the drive-side drop out), with a 6-speed Regina Extra Oro freewheel and Sachs chain (don't know the chain model). It shifted adequately but one tooth on the small cog of the freewheel was cracking and didn't look long for the world; other cogs were worn, and the freewheel itself sounded a bit rattley. Thus I switched to another freewheel, a 6-spd Regina CX, and I replaced the chain with a Regina Oro. The Regina chain is NOS, and the CX hadn't been used much, i.e. no chain stretch or worn teeth. As far as I can tell, the shape of the teeth on the two freewheels would be identical when new.

Here's the problem. The Regina chain skipped fairly horribly on the fourth cog, and only the fourth cog. I checked for stiff links and found none. Then I put the bike up on the stand and turned the cranks, looking and listening for clicks, sticks, etc. When I found some irregularities, and there where several locations along the chain that had them, I consistently saw that one of the inner plates of the chain was getting hung up on the cog tooth. Further inspection showed that in the problematic links, the normal small gap between the bushing and the inner plate was missing and the gap occurred between the inner and outer plates instead. Some monkeying about with a chain tool reestablished the relative spacing of plates and bushings.

In listmembers' experience, is this kind of 'compression' of the inner plates a common problem with Regina chains? It's a rather tedious, if Zen-like, ritual to have to go through for the inspection of a new part. Also, why did the skip only occur on the fourth cog (15 teeth)? Curvature? The derailleur/freewheel clearance doesn't seem excessive, and the chain is on about half the teeth when on that or any other cog. Super Record derailleur, BTW.

Interested in hearing what you all think,

Joe Decruyenaere

South Pasadena, CA