Re: [CR]NR Large Chainring Grumbles Due To Chain Angle - Help

(Example: Humor)

Date: Sun, 11 Jun 2006 18:08:50 -0500
From: "John Thompson" <JohnThompson@new.rr.com>
Organization: The Crimson Permanent Assurance
Cc: CR <classicrendezvous@bikelist.org>
Subject: Re: [CR]NR Large Chainring Grumbles Due To Chain Angle - Help
References: <20060611051129.79779.qmail@web38914.mail.mud.yahoo.com>
In-Reply-To: <20060611051129.79779.qmail@web38914.mail.mud.yahoo.com>


dan kasha wrote:
>
> I just got my Raleigh International (campy NR) up and running, and
> everything works great, except the front chainring. I put on a new
> campy 49 tooth (no peg) for the large chainring, the inner is a 42.
> Everything looks right.
>
> The 42 works smoothly across all 5 cogs. The 49 does not like the
> top three, but is fine on the smaller two. It kind of grumbles, a
> sound from the front, and not due to the front derailleur.
>
> I put it up on my stand (or two pieces of wood clamped to the work
> bench), and I think I can see what is going on, the narrower plates
> of the chain rub up on the teeth before as the teeth go in, and the
> chain kind of gets yanked around a bit as a result.

Sounds like a chainline issue. If you have a straightedge (the one in the Campy toolkit is designed for this, but a metal meterstick works as well), you should be able to drop it into the gap between the two chainrings and it will line up with the middle cog on the freewheel (assuming 5-speed freewheel).
>From what you describe, I suspect you'll find it lining up with one of the outer cogs on the freewheel. The quick cure is to put one or more spacers behind the freewheel to move it out enough to line up properly. You may also want to shift the axle a little if the freewheel body gets too close to the locknut.

--
John (john@os2.dhs.org)
Appleton WI USA