I am currently working on a few builds/projects slowly but steadily, one of which is a PX10. I am in the process of building it back up but I am uncertain about what to do for the rear derailleur. The bike is in great shape but the FD is garbage and will be replaced by a Suntour that I have. The RD is where my conundrum lies. The original RD seems in OK condition but the jockey wheel needs to be replaced. I have another spare identical RD with the same issue. I would like to swap the original for a long cage RD but am unsure how to mount one of the long cage Simplex RD's because the mounting nut at the back is a hexagonal shape and doesn't seem to sit in the spot where the circular but/screw of the original short cage derailleur fits. I have two long cage options in the box. One is an all metal LX630 I gather and the other is the black/gold one. I do not know what model that is.


Using one of these Simplex long cage RDs would be preferable to doing any hangar tapping/filing but that is an option also.


I hope that I have explained my issue thoroughly and will happily expound as best I can...


Here are photos of the RD options.


Untitled by irishbx4th, on Flickr


Untitled by irishbx4th, on Flickr


Untitled by irishbx4th, on Flickr

I may be wrong but some simplex derailleurs were designed to only work with claw hangers. The ones on the bottom photo of...their bottoms (two criteriums) work on the forged simplex dropouts. The other two may need a claw.

[MENTION=319010]Narhay[/MENTION] I think you may be right. They both had claw hangars but I was hoping that they would work on the dropout since I have them in the box.

A lot of the parts are probably interchangable.

The one on the upper right doesn't appear to have a stop for the tabbed washer, so that body wouldn't work. The one on the upper left looks like it might have the stop.
Both on the bottom have the tabbed washer, obviously.

The long cages should fit on any of the bodys.
As they are all grubby, I would recommend taking them all apart for cleaning, and then rebuild one from the nicest parts: best jockey wheels, best body, best cage, etc.

I'll bet you have enough parts there to put together a nice one with the long cage, tabbed washer, and mounting bolt you need.

[MENTION=181007]HamboneSlim[/MENTION] I did not realize that the parts are interchangeable. So I can take the mounting part from one of the originals and put it on the long cage RD? So the one to attempt this with would be the black/gold one not the all metal LX630? Thanks!

Probably. The tabbed washer requires a stop on the derailleur body. The black and gold one appears to have that stop in the pictures.

Not all parts on all Simplex models are interchangeable, but I'd bet those you have are.

I certainly hope so. Sorry if this is an amateur question but I am a bit uncertain about what you mean. The tabbed washer is the washer with that protrusion at the top of the original RD where it attaches to the hangar? At the top rear underneath the mounting screw? Also where is the stop or what exactly does that mean? Sorry this is my first attempt at this.

The stop washer for the 630 series is different from the criterium/410 series (the lower 2 in your photo) I'm not sure if it would make a difference once loaded (the difference is on the rear rotation stop tab)

@jcb3 Do you happen to know the black/gold long cage model? I saw no identifying date or number. It sort of looks like this one.


https://velobase.com/ViewComponent.as...=108&AbsPos=40

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Derailleur Hangers Demystified - Red Clover Components

...scroll down a little to get to Simplex solutions. But fiddling around with modifying one of your existing long cage examples might work.

It's not that difficult to notch a tab in the dropout and just go with Suntour front and rear, which is probably the most durable approach. Just look at the pictures, and maybe look at a standard rear drive side dropout, go very slowly and carefully, if you decide to go that route.

Here's a photo mounted. The tab goes in front of the hanger.

If the pivot bolt is stripped on the stop washer (which is typical - the stop washer and pivot bolt are supposed to lock together) take a allen wrench to the front side when tightening the anchor bolt and rotate the pivot bolt to apply tension on the spring, then tighten the anchor bolt - the derailleur should rotate rearward and have tension when pushed forward.

You may want to install one of the lower 2 first to see how the spring tension works when installed. It may be a bit tricky the first time, but once you understand how it works, it is easy to get right.

Good luck

Joe

On the px I would use the one with the gold insert....all of the J wheels should interchange....it has been my experience that the plastic used on most of the simplex stuff will eventually self destruct so the all metal versions of the derailuers are the best in my opinion.
I have replace the JW on my SRD with Shimano...you will have to do a little drilling for the bearing but thats no big deal. You just have to find JW that have enough meat on them in the center.
Good Luck Ben

Funny, I have one just like that and thought I'd pop downstairs and look - and surprise! no markings.

Looks like a 810 - upper pivot should be interchangeable with the 410 series

VeloBase.com - Component: Simplex SJ810 GT

Consider carefully before mutilating the hanger!

...yeah. I'm sorry I just don't get this, but I respect those of you who feel that way. Other than some supposed collector value (and except for that big jump in the price of the small ones when the Japanese had money to spend on them), PX-10's, as fine a ride as they are, have never gone where I live for much more than about $400 on the local CL. I currently own five of them from the early 70's through the 80's Super comp models, and while I've been fortunate in not having to notch any of them, I'd do it if it were the best way available to fit a long cage rear.

No offense intended. I just take a more utilitarian approach to restoration.

+1 Most of the parts on this style Simplex DR are interchangble if you take them the whole way apart the cage assemble screws off and you can change the cages around.

Suntour pulleys are direct replacements for simplex ones FYI.

Yes, that is what I meant by the tabbed washer; it's the one that forms the stop against the hanger.
The derailleur body should have a flat that fixes the edge of the tabbed washer in place on the derailleur - you can see it in your pictures of the derailleurs with the tabbed washers.

Taking them apart also affords the opportunity to clean and grease springs #4 & #11, which will help keep the derailleur action springy.
Note that those springs are handed - they have to go back into their respective barrels in the derailleur body.

No offense taken - it is a good point to be able to modify it if you don't like futzing around with simplex.

You can mount a Crane GS or Campy Rally without "notching".

Search verktyg's posts if you want to learn all about the issues involved with Simplex rear derailleurs and hangers.

Thank you all. I am going to try the route that [MENTION=181007]HamboneSlim[/MENTION] suggested by mixing and matching the best parts first.

I noticed that a couple of those RDs seem to have their jockey wheel cages clocked back too far, as if you do not have the cage stop screws installed on the outer cages, near the lower pivot. The stop screw is part #15 on the exploded view of the RD posted on this thread......
It will make it much easier to install the RDs with those stop screws installed, as you will not be fighting the lower pivot springs too much.

Follow up:
I interchanged the upper pivot from one of the Criterium 410s with the one from the long cage 810 and it works perfectly. The tutorial was very helpful so I want to report back to confirm that this method works seamlessly.

Untitled by irishbx4th, on Flickr

Excellent work, we love it when a plan comes together, well done!