The second tensioning cable on the Simplex Juy 543 and Juy 51 derailleurs is attached to the regular cable a few inches forward of the double cable stop on the chainstay. Therefore there is a single cable gong around the b/b and two cables going between the junction and through the double stop on the chainstay. Unlike the Huret Louison Bobet derailleur which has two levers and cables the Simplex uses only one lever to change the gear and tension the chain.
Mike Barry. Fiddling with derailleurs on a very wet day in Toronto, Canada
When helping a friend assembled his reshly repainted '58 Peugeot PLX-10 or '59 PX-10 I noticed something strange:
the right chainstay had a double cable derailleur cable-boss the same chainstay had a single cable cable-boss near the BB the down tube had a single cable cable-boss near the BB
If the bike was designed to use a twin cable Simplex 543, why aren't all cable bosses double?
My Hirondelle, which uses an "endless" cable has double cable guides throughout.
Anyone have close-up photos of a '58/'59 PX-10's cable guides? Anyone have the instructions for the 534 rear derailleur?
Amir Avitzur
Ramat-Gan, Israel