[CR] Simplex barcon "demultiplicateur"?

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Date: Sat, 23 Sep 2006 07:22:18 -0400
From: "Harvey M Sachs" <sachshm@cox.net>
To: theonetrueBob@webtv.net, Classic Rendezvous <classicrendezvous@bikelist.org>
Subject: [CR] Simplex barcon "demultiplicateur"?


I first saw a "demultiplicator" decades ago, just after most of the transition between "plunger" and parallelogram derailleurs. The plungers needed to take up a LOT of cable, so their shifters, often braze-on, had a large "barrel" diameter. Parallelograms take much less cable movement. So, the folk wisdom was that the demultiplicator (what an ugly word!) served to reduce cable throw, allowing you to keep your old DT shifter lever when you converted to the new derailleur.

There's a little irony here: I'm using one on my Hetchins, which has early Shimano bar-cons, to space out the lever throws a bit - the application that Bob Hanson suggested.

harvey sachs mcLean VA USA

+++++++++++++++++++++++++++++++++++ Bob Hanson wrote: Can someone please explain this piece to me?

This was the relay attachment hinged to the rear derailleur cable guide which would be clamped above your bottom bracket (on the down tube).

Was this intended to simply reduce the distance of travel on your rear barcon shift lever? And, was this useful?... Necessary?... Just a weird French 'truc'?

Nobody else used anything like this, only Simplex, so I assume there was something uniquely quirky about their "cross-commandes" [barcon levers] alone.

Curious if these shifters actually functioned well,... especially with this additional bit of French technology designed into that system. I've never known anyone who has actually used a set.

[Whaddya think, Jerry?]

Bob Hanson, Albuquerque, New Mexico, USA