hagen2456

After having build back up my 1956 Crescent racer, I really enjoyed how the Juy 543 worked very nicely for some time - but now it won't shift to the largest cog. Seems that the axle behind the big "flat" spring has somehow become too lose. Is there any way of tightening it?

Chombi

Not familiar with those older Simplex RD's but you might have to check whether the axle is attached through a swaged joint or if it is just threaded on. If it's swaged, it will be tricky to get it tight again as trying to tighten a swage out of the factory is literally hit and miss if you do not have similar equipment that was used originally (some sort of hydraulic press with possibly proprietary to the component press heads, I presume) If it's a threaded joint, then it's simpler, ......that is, as long as the threaded hole and shaft are in good condition and the hole not ovaled in some way.

Chombi

jjhabbs 

Not sure. But I do have a NOS NIB model for sale. Its on Ebay..look up juy 543. maybe you can show me on skype what your tlaking about and I may be able to help.

Chombi

From what I read above, I think he is saying that the shaft (if there's one) under the coiled flat spring is loose at either the cage or main pivot body end and there's to much resulting flex in the mechanism because of it so it would not pull the chain over to the biggest cog with the shift cable pulled against the lowest gear stop. How does one re-tighten the connection of that shaft to wherever and how ever it's attached to...

Update:
from what I can see in this link of pics of the mechanism taken apart:
https://www.flickriver.com/photos/pou...7625889807732/
It looks like there might be no shaft under the flatcoil spring, but the coil spring pretty much is collapsed on to itself as the cage is pulled closer to the derailleur body for shifting to the lower gears. I'm wondering now if the stiffness of the coiled spring extension might be controlled by the tension adjustment of the coiled flat spring which seems to be incrementally adjustable with a cotter pin sitting in slots at the base of the spring holder on the derailleur body.

Chombi

hagen2456

Thanks for the suggestions. I'll check the tension thing.

Chombi

I found another pic that cold helpus understand how the mechanism works:
https://www.ebay.com/itm/NOS-60S-SIMP...item519ed0abe4
It's an eBay auction for parts on these old Simplex derailleurs.
Looks like what I thought was a cotter pin is actually part of a conical spring that goes in the coiled conical flat spring.
You can still try to adjust the inner spring tension by moving the end of the spring around that slotted spring nest. But I'm thinking now that maybe these spring parts could have also lost their spring tempering over a long time of use. You might also just consider replacing these parts for new ones (looks like they are cheap enough to at least consider doing anyways). Still no sign of an actual derailleur body anchored shaft for under the flat spring though, except for the one connected to the end of the shifting chain and the derailleur cage. You might double check the chain/cable connection in the derailleur body and see if that can be shortend to make the derailleur shift a bit further into the lower gear side.

Chombi

John E

I gave up cursing at my Cyclo bandspring derailleur and replaced w/ a first-generation Campagnolo, which worked far better. I don't like the normal-low function, which throws the chain into the spokes if the shift cable snaps or the shifter slips.

hagen2456

Yeah. You seem to be right. I'll try tightening the inner spring.

hagen2456

That's certainly a potential problem to consider. The cables are brand new, though, and I can't see how the shifter should "slip".

rhm

I realize this thread is about the 543 derailleur, not the Tour-de-France model, but since we're digressing to talk about other bandspring derailleurs anyway....

I have heard of this problem many times, and it always perplexes me. With no tension on the cable (or no cable, or a broken one, etc) the derailleur should line up under the biggest cog. It should not go into the spokes. I know, I said should. In the real world things may be different. But the best way to get this kind of derailleur to work well is to make sure it is adjusted the way it should be. On my 1954 Drysdale (with a five-speed Tour-de-France derailleur from JJHabbs) I was able to get the proper alignment of freewheel and derailleur by respacing the axle (a thicker washer was required, to move the wheel to the left) which entailed redishing the wheel. And I think I have to add another very thin washer since once, on my ride on Sunday, I shifted slightly beyond the biggest cog-- not quite into the spokes but the chain was skipping along the top of the teeth, not a good thing at all).

In more extreme cases, where it's not enough to add a washer or two to the axle, the derailleur arm (the piece at the very top in the ebay ad mentioned previously) is probably bent. The solution, in such a case, is to straighten it. This won't be easy; it's a pretty tough piece of steel.

I had a Raleigh Lenton Grand Prix for a while, with a Cyclo Benelux derailleur and a four speed freewheel. The derailleur was somewhat bent, as is often the case, so 5 mm of axle washers were needed. Furthermore the original freewheel was pretty worn out, and quite a challenge to remove from the hub, so I elected not to use it. With the extra axle length I was able to mount a five speed freewheel, and the Cyclo shifted pretty well among the four biggest cogs. Not surprisingly it never got into the 14T.

Anyway, my point is, if it is too difficult to adjust the derailleur, you may be able to get the same effect by adjusting something else.

jjhabbs 

I have tons and tons of springs and other parts for Simplex Tour De France if anyone needs them.

zidortri

I sent you a message as I have an issue with the chain of my Juy 543 but I just realized that I only have six posts so far on the whole forum - which will be seven with this post, and therefore cannot send nor receive messages...
Fortunately I have a few interesting things to say - at least so I think 🤔, on the couple of previous threads where I posted previously so hopefully I will be able to message you...

kroozer 

Is there a an on-line tutorial for these coil-spring derailleurs anywhere? I have a Huret that I'd like to try, but really have no idea of even the basics.

jjhabbs 

I did get an email from you. I returned one. But didnt hear from you since. Let me know if you need anything.

John

John E

The worst-case scenario is the cable snapping on an upshift and the derailleur slamming against its low-gear stop, with momentum carrying the chain over the large sprocket. This is one place a spoke protector would make sense.