Classic & Vintage - Help! Strange Shimano 600 Downtube Boss shape

Hi,
I've got a question for an 80's Schwinn/Shimano expert out there. I have a 1984 Schwinn Super Sport that I'm trying to adapt for bar-end shifters. The current setup is downtube Shimano 600 shifters. I was told at my LBS that because of their thin profile these friction shifters were an 'aero' version. I bought a set of Shimano downtube cable stops, but when I removed the shifter levers, the boss' shape had a weird round base with a key shape(?) in it that points up the bar, toward the handlbars (see pictures below) The cable stop won't fit over the boss' base.

So my question is, are there downtube cable stops available that will fit this strange boss shape? I'd like to avoid the clamp-on type stops if I can. I could find very little in the forums other than these bosses are strange and sometimes called Italian style bosses.

Any help would be greatly appreciated.

I modified a set of Shimano Light Action DT friction shifters to bar end using the Riv pods and used the original clamp with the modern aluminum Shimano cable stops. Fitting required a fair amount of material removal from the back side of the stops to clear the keyed base.

Thanks for the suggestions raverson and Bob. I think I'm going to try Dremeling out the the back of the stops. I did some measuring and think I can remove enough material in there to fit over the stop's keyed base, as you both suggested. This way if I ever want to go back to the original downtube shifters I haven't messed up the original boss shape.

Thanks again!

um, is that eared piece part of the boss or is it removable?

It's part of the boss. although it almost looks like it's more part of the frame. Either way it's definitely not removable (aside from grinding it off) From what I've gathered this was a weird boss base style used only in 1982-1984ish schwinns and it's hard to find anything out about them.

How did you get on with this? I have the exact same problem.

Shifters were Shimano 600 and the bike is a Paconi made by Kevin Wigham. I'm guessing its from the early to mid eighties.

Interestingly I notice from one of the threads below that the braze-on in question is refferred to a "A-type", if I am not mistaken.

http://www.bikeforums.net/showpost.php?p=9873458&postcount=5

How did you get on with this? I have the exact same problem.

I took a Shimano 600 Arabesque shifter (shown at right - Shimano 105 Golden Arrow at left) and ground it down to match the style of my Campy Victory components:

http://www.jaysmarine.com/Shimano_600_shifterpolish_4.jpg

One could do similar to the Golden Arrow as well.

-Kurt

Does anybody know if taking the arabesque downtube clamp on shifters and removing them from the clamp would work on the bosses mentioned above?

Shimano was so enamored of this new "standard" that they made adapters so that you could fit your Shimano shifters onto Campy (the real Italian style) braze-on bosses. Check out the top of the diagram posted in this thread (http://www.bikeforums.net/showthread.php?p=9903462#post9903462). It's too bad they didn't make an adapter that did the reverse -- turn their reverse-keyhole boss back into a Campy boss.

If the cable stops that fit a Campy boss will (or can be ground out to) fit over the Shimano boss, perhaps you could grease up the boss and downtube, and fill the interior of the cable stop housing with wet plaster or (if you're brave) epoxy. Then install, cure, remove, degunk, and reinstall.

Does anybody know if taking the arabesque downtube clamp on shifters and removing them from the clamp would work on the bosses mentioned above?

Yes, but you must have the crescent-shaped adapter made for fitting these shifters to the braze-ons (the grey pieces in the photo of the blue Raleigh below). They must be adapters for this design - later ones will not fit properly.

-Kurt

Thank you, I will look for those adapters then.

... So my question is, are there downtube cable stops available that will fit this strange boss shape? ....

No.
(Shimano proprietary design. No one other than them cared for it.)

Any update on this? Does anyone make a cable stop that will fit over the keyed area, or will I have to put a dremel to some shimano units? I want to put bar ends on my gf's bike.

Any update on this? Does anyone make a cable stop that will fit over the keyed area, or will I have to put a dremel to some shimano units? I want to put bar ends on my gf's bike.

No adapters have been designed in the meantime. Before you start cutting stuff up, try using a pair of these - they'll serve the purpose, and re-route the cables so that they do not rub the bosses:

http://harriscyclery.net/images/library/catalogs/soc/p350X350m/BR5456.jpg

http://www.google.com/search?um=1&hl=en&client=firefox-a&hs=oVS&rls=org.mozilla%3Aen-US%3Aofficial&biw=1920&bih=921&tbm=isch&sa=1&q=problem+solvers+backstop&oq=problem+solvers+backstop&aq=f&aqi=&aql=&gs_sm=e&gs_upl=232l470l0l3l3l0l0l0l2l272l427l0.1.1

-Kurt

Thanks for the link Kurt, I've seen these problem solvers before. The problem is that I want to be able to use the braze ons, I don't like just having them exposed. I already have a extra set of these: http://lh3.googleusercontent.com/public/9TIgkWIQnG1pMkDWp67UisZhjI7B2MuC38JJ_zkHWT4lP6B__bmQEszKAnDGZbV4A4ptpknoWd2hEsVmkbk9J-k0trJUzJkzJksXfrCiQWHn-wvdpktBk7_n472ICrVrrVwlPDOdBJH09VHYhNBy5IN5JWJ2k2FtNg9gRdK5AZAKzgTMVdgy8SVrf0Y

so I was thinking about just slotting out a section so that it will fit over the key.

I dealt with this last week on a Ross 290S. It came to me with incorrect Suntour DT shifters so there was no stop. The levers could be pushed very far forward (past parallel with the DT). I scrounged up an pair of Shimano 600 DT levers from the same era.

Thanks for the link Kurt, I've seen these problem solvers before. The problem is that I want to be able to use the braze ons, I don't like just having them exposed.

You might want to find a different frame then.

-Kurt

so I was thinking about just slotting out a section so that it will fit over the key.

Yeah I ended up just dremmelling the cable stops and was very happy with result. :thumb:

Yeah I ended up just dremmelling the cable stops and was very happy with result. :thumb:

i would think this is the smartest idea.. just modify existing cable stops to fit

207250

Well done - very nice. Did you have to shim the casing to fit the smaller bolt, or was it a drop-in fit?

-Kurt

207250

that looks awesome. i'll have to set aside some time this weekend to do the same. what bits did you use?

No shims, it all just bolts up nice and snug re-using the old bolts. The new bolts didn't fit.

I used a bit like the "100" one in the image, and a cheap imitation dremel. I could made it all fit a bit more neatly but the tool kept overheating in my hand. I now have a proper dremel.

207387

thanks for the tip philg!

The new bolts didn't fit.

They're tapped to 4.5M. Not an easy machine screw to find. When I ran into this issue I just tapped the boss to 5M x 0.8.

They're tapped to 4.5M. Not an easy machine screw to find. When I ran into this issue I just tapped the boss to 5M x 0.8.

they certainly are! I recently aquired a frame with these bosses (and oddly dropouts drilled for a Portacantena holder). I bought NOS shifters from Loose Screws listed as having 4.5s but were in fact standard 5mm. DivineandBright was nice Thank You again