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

(Example: Framebuilders:Mario Confente)

Date: Sat, 10 Jun 2006 22:11:29 -0700 (PDT)
From: "dan kasha" <dankasha@yahoo.com>
To: CR <classicrendezvous@bikelist.org>
Subject: [CR]NR Large Chainring Grumbles Due To Chain Angle - Help

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.

Anyone experienced this? Here are my observations:

1) I did not check the BB markings when I rebuilt it, but it looks right, the small chainring is 3mm from the chainstay.

2) The chain is not stretched, and looks like an older style chain, with parallel plates, and the pins have little center dots in them if you know what I mean.

3) The rear wheel is properly dished, but I am not certain that the hub is in the right spot. It is a NR that has a 5 speed cluster, but was spaced at 126mm. The distance from the non freeweel dropout to the hub body is 11mm, which tells me the hub is not too far over to the left, but not totally certain.

Thanks in advance. Otherwise the bike works great. Oh, and sloved my short steerer problem by using the lower portion of a tange chrome headset, and the nice NR top. Gave me all the space I needed, and looks almost right - best I could do.

Also, was passed by the Seattle branch of the World Naked Bike Ride today. Did not see any vintage lightweights there. Dan Kasha Seattle Wa

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