dddd

Quoting their site, "It does not compromise the shifting in the smaller cogs of the cassette but yet it enables the derailleur to work with as large as a 40T cassette".
I can't see how this would be true, since the chain gap tends to be a determinant of how quickly that a shift can be completed and how well that indexing works.

Some indexed systems are reported to still shift acceptably with one of these devices, and you may be able to compensate to a great degree by adjusting the derailer's B-tension screw (since you aren't going to be using a 40t cog), but these things aren't magic and the chain gap can always be a big deal on a derailer bike using modern chain.

cudak888 

Or for the RD upper bolt to bottom out on the cast hanger.

I still think the classiest way about this would be to 3D print an alternate Shimano upper tab designed to work around the Simplex dropout. Definitely the least cost effective, but without a doubt, classy.

-Kurt

SB_Greg

If I could wrap my head around this I’d consider it. I do have access to a 3D scanner where I work.

cudak888 

Scanner would be horrible - it creates far too many unnecessary verticies completely off plane from what any human would consider an intuitive 3D object.

It would be easier to model the circle shapes and whatnot from scratch in Blender. 3D Hubs might have the right material for printing.

The most difficult part might be clocking and compressing the spring and upper bolt just right.

-Kurt

SB_Greg

SlBS50 8 speed. From 1994?

KCT1986

That seems to be the Dura-ace compatible model. Marked with "8s" on the ring that says SIS/friction(?), probably under the D shaped handle in your pic. If this is the case, then the cable pull is for the FD-740x series. Same pull as the BS77 with 1 less detent.

With most Shimano RDs it requires alternate clamp position as Sheldon Brown shows. As mentioned earlier, some ? on reliability as the exact alignment of cable at the clamp point is needed. Certain RDs have a plate with tabs that replace the round washer on the clamp bolt which helps with the alternate routing (see Sheldon's diagram).

I think a few of the late '90s - 2000 had the plate with the tabs. Just align as pictured and see if it works. May require a little fiddling to get best performance.

SB_Greg

Success!!!
Recap: Shimano Dura Ace SlBS50 8 speed bar end shifters
https://www.dropbox.com/s/o4pyujazb5...19.21.mp4?dl=0
I spent a few hours at my COOP where I found a medium cage Shimano Ultegra 6600GS rear derailleur. I think these were released in 2005.


Critical for this project was the Suntour claw hanger #4532 . I tried using a different Suntour hanger and it was too short. Thus, the derailleur hole on the hanger didn't match the one on the Simplex dropout. However, the bolt that comes with the #4532 is too short to thread over the hanger and the Simplex drop outs. So I had to find a longer bolt. the one I found at the COOP was slightly too long and I had to compensate by using two washers.



After installing the #4532 hanger, the derailleur, a chain, and a derailleur cable I quickly learned that the chain rubbed against the specialized nut of the Simplex #4532 hanger. I addressed this issue by placing a washer on the axle/spindle on the inside of the Simplex dropout. This worked as it created space so that the chain no longer rubbed. I admit that I don't like that a washer is hanging around loose like that and maybe there is a better long term fix.

After this stage it was a normal process of derailleur adjustment. The indexing worked fine. No need for the alternate cable routing that Sheldon talks about. The end result? It shifts great in index and friction mode. I bought a couple more Suntour #4532 hangers for when I do this again in the future.

noobinsf 

Wow, great work, and thanks for documenting this so thoroughly!

KCT1986

Congrats, glad it worked out.

Interesting that the RD worked out. Guess that since you are using the low end (closer to hub) of the RD's range (because of the claw), the actuation is large enough to work with the reduced pull of the shifter. Good info to know.

cudak888 

Fantastic. You are exceptionally lucky that the 4532 lands dead-on in the same spot with the Simplex drop, and that it's wide enough to accommodate the B-pivot screw too. Nicely done.

-Kurt