Re: [CR] Simplex barcon "demultiplicateur"?

(Example: Framebuilders:Tony Beek)

In-Reply-To: <23763-4514EC22-12654@storefull-3274.bay.webtv.net>
References: <23763-4514EC22-12654@storefull-3274.bay.webtv.net>
Date: Sat, 23 Sep 2006 11:45:28 -0400
To: theonetrueBob@webtv.net (Bob Hanson), classicrendezvous@bikelist.org
From: "Sheldon Brown" <CaptBike@sheldonbrown.com>
Subject: Re: [CR] Simplex barcon "demultiplicateur"?


Bob Hanson a demandé:
>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'?

No, it actually _increased_ lever travel if installed as intended. This made shifting less finicky

Simplex derailers were fussy enough shifting with down-tube levers, and if you used the barcons without the demultiplier, fine tuning of the shifting was nearly impossible.

These shifters were also known for rapid consumption of cables. Use of the demultiplier reduced cable tension, and thus cable friction/wear.

Functionally it's equivalent to the current "Travel Agents" used for matching brake levers in mixed long-travel/short-travel brake systems.

Sheldon "Mechanical Advantage" Brown +------------------------------------+ | France, France...if not for you, | | the world would be alone! | | --Victor Hugo | +------------------------------------+ --
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