Re: [CR]Three Arm Chainrings

Example: Framebuilders:Rene Herse

From: "Pete Geurds" <>
To: <>
References: <>
Subject: Re: [CR]Three Arm Chainrings
Date: Sun, 7 Aug 2005 17:58:06 -0400

From: "Jerome & Elizabeth Moos" <> Subject: Re: [CR]Three Arm Chainrings

>I measured the hole-to-hole distance on the 3-arm TA Professional on the
>70's Mercier I've just built up for my wife for Larz, and on a Stronglight
>3-arm steel cottered crank I recently bougt from Hilary. They are the
>same. However, rather than a hole which the attaching bolt passes through
>on an alloy crankarm, the steel crankarm has a smaller threaded hole, which
>the attaching bolt threads into from behind. Is this a special bolt, or
>can some common type be used? Also, on the Stronglight rings I lost on
>eBay, it looks like the outer ring was 6 holes, three used for attaching
>the crankarms, the other three used for attaching the three-hole inner
>ring. Anyone familiar with the hardware used to attach alloy rings to
>cottered steel cranks?

-------------------------------------------------------------------------------------------------- I believe 116mm is the bolt circle on Nervar, Stronglight and many similar three arm cranks. My Nervar crank uses 7mm bolts. 7mm short bolts(for single ring) are sort of scarce in many places. I don't think an alloy ring would take a different bolt but a washer to prevent galling couldn't hurt.

Pete Geurds
Douglassville, Pa