After ruining 4 tandem cables and searching the internet in vain for guidance, I think I have now successfully set up the French Cyclo shifter and derailleur on my 1947 Camille Daudon.
The only catalogs I was able find were these exploded drawings of Cyclo’s British models, which vary somewhat from the French model I was working on. While the general concept is the same, the British version has cable stops both at the derailleur mechanism as well as at the shifter lever.
This is the wrong way to do it.
Without the cable stops, one is left to mangle the cable while trying to tension it and ponder wrapping, double wrapping and twisting techniques to make the mechanism line up correctly and shift properly.
If you enjoy working with tiny tools or are perhaps a clockmaker or camera repairer – this job is for you! After identifying the basic tiny parts needed – a nipple for the rear derailleur cable, and a “conjoiner” for the shifter, and the related miniature Allen wrenches and screwdrivers – you are ready.
After shifting the bike by hand to the middle gear, this bike’s rear slot landed at about 9 o’clock. I installed the nipple and then wrapped the cable around twice. Oh, I forgot to mention that you’ll need to use a tandem cable, cut off the ends, and then put the nipple about at the midpoint. Once installed, I used a surgical clamp to hold the cable in place. (Perhaps a surgeon would also enjoy this job.) Okay, now for the hard part.
Threading the cables through their guides, you’ll end up with two ends to be “conjoined”. After that cable fraying process comes the daunting task of figuring out how to loop the cable properly so that the shifter ends up in the right position. I turned the shifter upside down and backwards, put the “conjoiner” in its slot, and then twisted the cable and threaded the shifter through the twist, and voila~! The shifter is upright and the slot position looks good – and now it’s time to adjust the tension.
This turned out to be the more time-consuming and injurious (the now frayed cable ends caused numerous puncture wounds) part of the procedure. I ended up identifying one of the cables with some blue tape so I could determine which end needed tension. I put the shifter in various positions during this process to learn whether the tension was right across this 4 speed drive train’s movement. It was trial and error, lots of the latter.
One of the things that kept happening as I was adjusting the tension was that the nipple would come out of its slot – even though double wrapped. I came up with this temporary solution, shown above, of installing a small rubber band attached to the derailleur mount, which helps to keep the cables aligned. Once the system stretches and the shapes break in, I will adjust the tension again and decide if the rubber band is still necessary.
Whew! With the shifting now moderately functional, I am looking forward to rebuilding the hubs – or any other job that doesn’t involve tiny tools and puncture wounds.
UPDATE 4/30/14:
While paging through a copy of a 1956 Le Cycliste magazine I came across this advertisement. The rear cable is routed through the derailleur spring! This solves the problem of keeping the cables aligned while shifting through the gears. I am going to re-route the cables and hopefully that will solve the problem.