[CR]Re: Huret's sheet metal methods

(Example: Racing:Roger de Vlaeminck)

In-Reply-To: <445A9460.6030203@cox.net>
References: <JJEEKLDDELHGFDGDBELBMEADDDAA.avitzur@013.net.il>
Date: Thu, 4 May 2006 20:18:35 -0400
To: Harvey M Sachs <sachshm@cox.net>, Amir Avitzur <avitzur@013.net>
From: "Sheldon Brown" <CaptBike@sheldonbrown.com>
Subject: [CR]Re: Huret's sheet metal methods
cc: Classic Rendezvous <classicrendezvous@bikelist.org>

Harvey M Sachs wrote:
>I'll agree with Amir that the Huret Challenger is nice, but it just
>went about its business of shifting the chain. It was hardly the
>most interesting FD Huret did. For that, I have a couple of nominees:
>
>1) The early '60s unit that was paired with the Allvit (and all
>others). This one had key differences from the competing Campy
>"GS" "plunger-in-a-box" road grit accumulator: it was a
>parallelogram, and all sheet metal except the rod and bolts. So, it
>inherently worked better. But, it also had one similarity to the
>unlamented Campy: there was only one stop screw; the other
>adjustment was made by sliding the rod along the attachment bolt. In
>the case of the Huret, you first adjusted the inner limit (with the
>rod sliding), and then the outer limit with the screw. A corollary
>of using the round rod was that the angle of the cage could be
>adjusted, so it would work (more or less) with bent-tube bikes.

The ability to change the pitch angle of the cage was sometimes very useful. I used one of these on my Moulton Mk.3 with a custom made 72 tooth chainring. No other front derailer would work.

For some reason, none of the older front derailers would upshift well without a bit of tweaking. The trick was to use an adjustable wrench to bend the forward tip of the inner cage plate to the right a bit. That way, once the chain had risen up to the level of the bigger ring, the bent tip would shove it over so it would mesh.

This modification made a HUGE improvement in upshifting.

Modern front derailers have much more 3-dimensional cage plates, and don't generally need a lot of surgery unless you're using unusual chainring sizes.

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