Well some combos you could not use them on. My 1974 Raleigh Super Tourer has a Jubilee RD (original) and Suntour barcons (not original). The barcons use all their travel just to shift the 14-28 FW. With the demultiplicator I'd only have maybe three rear gears.
Regards,
Jerry Moos Big Spring, Republica de Tejas
Sheldon Brown <CaptBike@sheldonbrown.com> wrote:
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.
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