Upgrading old Schwinn FD to Shimano 105 (both bottom-pull), and there's no housing stop on the 105. Can I get by without one and avoid running the cable under the BB? Or are there single clamp-on stops for sale anywhere?

did your old FD use a length of cable HOUSING? If so, I think you either have to use a new FD that can accommodate housing or you'll need a clamp-on guide that directs the bare cable over the BB shell, whether you use the other side (for the RD cable) or not is up to you, (you could even grind it off). I suppose you could fit a clamp-on stop on the seat tube below the FD, but never tried that (and you might have issues with interference of the bolt, etc.).

That's a little Schwinn weirdness. Pretty obviously there has to be a cable stop somewhere. The Shimano was designed with the idea that there'd be either a straight run of bare cable from the DT mounted shifter under the bottom bracket (or over but that's pretty archaic) or a stop on the downtube with cable housing going to whatever other sort of shifter there was, bar-end, stem, brifter.

If you can come up with a clamp on stop or convert to DT shifters you can use one of the little plastic cable guides that shimano sells that screw on under the BB. Like this: https://aebike.com/page.cfm?pageid=30...ils&sku=FS1092

That's exactly what I did, with a ~3" piece of housing. Works perfectly.

Which model Schwinn are you doing this to? I ask because tubing size varies between models and makes a difference with the clamp you plan to use.

I'll assume on your down tube near the BB shell there are two braze on cable stops. A possibility would be to use a "Problem Solver" cable stop near the bottom of your seat tube. Not elegant, but very sturdy and functional.

I used several when I upgraded my Twinn Sport to have a quad brake system and went to a triple crank. You can see one on the tube just above and to the right of the crankset. I had to shim mine in order to fit the narrow diameter tubes used on this model Schwinn. I believe Niagara and EBike carry these. Best of luck.

I have two or three of those bb cable guides, with stops for both the RD and FD, both Shimano and Suntour. If you need one, let me know.

I also have a NOS Campy one, never mounted, chrome.

This is a 1977 Le Tour II, with a 28.6mm seat tube. There is no screwhole to mount an under-BB cable guide, and I'm not prepared to drill & tap one.

Now that I'm looking at it, I think I can fit one of those DT cable guides (with a housing stop on the left and an angled guide on the right) and Dremel off the RD guide. Clearance shouldn't be an issue, since I can mount the guide at least a couple inches below the FD clamp.

That's a lot of cabling, pastorbob.

Put away the Dremel.

-Kurt

I just did this to a Varsity last week using Deore Derailleurs. Be sure you've got everything screwed down well....I broke the mounting bolt of a cable stop doing exactly this last week.

My solution was to disassemble the original FD and remove the cage. Then I used the remaining clamp and Cable stop that was part of the original FD as a cable stop mounted directly below the new FD.

I'm on my way home in a couple of minutes, I'll take some pics to illustrate...but its very similar to Pastorbob's solution.... I actually tried the problem solvers clamps but found the mounting screw to be very weak and accidentally broke it.

If you can find one of these... they seem to be hard to come across for some reason, I happened upon one by buying a random junk box full of stuff.

I think the campagnolo ones had long guides like that on both side, where shimano usually just had the long guide for the rear and just a stop for the front.

Here's the Disassembled Schwinn GT290 Front Derailleur as a cable stop for a Deore XT FD.


You can see the cylinder in close next to the small chainring. Thats where the cage used to be. Its just a screw that holds it on...I can still bring this back to be a derailleur if i was insane. Clearance with that chainring isnt roomy, but its not too bad.

thanks to pastorbob for the brass bearing tip to fit standard clamps to old schwinns.

I have one of each.

Sorry Kurt, have to disagree with you there - instead keep the Dremel out but use it to cut off the rear derailleur cable guide on the clamp-on fitting. leaving the brazed-on fitting intact on the frame.

No braze-ons on this bike whatsoever, except for a small nub for supporting the upper clamp-on DT guides (and in the future clamp-on DT shifters). I'm liking the original FD disassembly idea, because that saves me a trip to the greasy parts bin.