Simplex JUY 51/53
Author and images - Peter LowryBelow are shown details of a Simplex rear changer - Juy 51 and the matching front changer - Juy 53, both fitted to a 1951 Hobbs 'Blue Riband'.
Both the tension cable and the gear cable share the same outer rear of the chainstay cable eye. The tension cable is attached to the gear cable by a pinch-nut and bolt, just ahead of the chainstay cable stop. The second cable helps the inner coil-spring to increase the chain tension. To make a thin tension cable - first cut a length of approximately 12" of conventional brake cable, then peel away about 12 strands of the fine wire cable and then you are left with a fine inner core which is about the same diameter as the original Simplex tension cable!
 Simplex twin-lever
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 Twin cable pulley at bottom
bracket
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 Front changer
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 Detail of single-to-double cable
fixing
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Simplex JUY rear changer showing
twin cables