I recently got a Simplex rear derailleur off eBay ( Item number: 350025309847 ) to go on my 1951 Claud. I was looking for a Simplex Tour de France because that's what I remember was used in the early 1950s and that's how this was originally listed, but it was then revised to "Simplex JUY". This derailleur looks identical to the Tour de France with the exact same jockey wheel pivot point except that it's stamped "JUY". So what's the difference? Was it originally JUY and became Tour de France later? What does JUY mean? Most JUY changers I've seen look a lot different and maybe came later.
Also, the one I got is a 4-speed (marked "4-vit.Chaine 3.17"). I know I once converted one of these to 5-speed by changing a part, but that was over 50 years ago and I don't remember exactly what I replaced. Anybody know? Maybe just a bit of machining of one of the parts will give it more travel. Thing is, my dropout spacing is 115 mm so maybe a 5-speed block won't fit or the hub will require too much re-spacing and re-dishing. The trouble is that 4-speed blocks are now rare as hens' teeth (i.e. expensive) and I haven't seen any with the tooth range I'd want anyway. Any help would be appreciated.
John Betmanis
Woodstock, Ontario
Canada