Re: [CR] Huret derailleur mounting, was: Posting blunders

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In-Reply-To: <000701c8a965$6323f0f0$4001a8c0@compaq>
References: <a062309d9c43bd33909e0@[192.168.1.33]>
Date: Mon, 28 Apr 2008 17:13:52 -0700
To: "David Snyder" <dddd@pacbell.net>, classicrendezvous@bikelist.org
From: "Jan Heine" <heine94@earthlink.net>
Subject: Re: [CR] Huret derailleur mounting, was: Posting blunders


At 11:23 AM -0800 4/28/08, David Snyder wrote:
>You explained how the Huret mounting bolt(s) allowed adjustment of
>the freeplay at the B-pivot. I had always wondered why my Trek710,
>with it's Duopar derailer, made wheel removal so difficult as the
>derailer didn't pivot at all with the bolt torqued down and the
>wheel was thus barely removeable.
>I checked the bolt and find it to be hollow, but with no internal
>threads. Any idea how the pivoting action is supposed to be effected
>on this one? There's a washer between dropout and hanger that looks
>a bit less than original to me, so perhaps the bolt is stepped and
>was to bottom out against the dropout instead of the derailer body,
>with some long-lost positioning hardware intended to take up the
>space between the derailer and hanger?

No, the washer is correct, and there shouldn't be anything else between derailleur and hanger.

There should be a nut on the inside of the dropout that acts as a locknut. This nut often is missing, as mechanics just tighten the bolt and figure that is all you need. Indeed, the derailleur stays in place, but as you observe, it cannot swing to clear the freewheel when you remove the wheel.

Instead of tightening the bolt all the way, you tighten it just so much that the derailleur swings without play, then lock in that adjustment with the locknut on the inside of the dropout. The locknut screws on the outside of the fixing bolt, which is a bit longer than others and protrudes on the inside of the derailleur hanger. The locknut has the same threading as the derailleur hanger eye of the dropout.

For exploded diagrams and detailed instructions, refer to the article on overhauling a Huret Jubilee derailleur in Bicycle Quarterly Vol. 5, No. 1.

Considering how many Huret derailleurs must miss the locknut, it might be worth while to remanufacture them. Making them would be simple enough. So far, I have done OK by cannibalizing other, broken or worn Huret derailleurs...

Jan Heine
Editor
Bicycle Quarterly
140 Lakeside Ave #C
Seattle WA 98122
http://www.bikequarterly.com