How to get rear derailleur cable house to run straight on vintage steel frame?
 

I'm trying to build up a vintage steel bike for the first time and got to installing the rear derailleur. However when I tried installing the gear cable and rear derailleur cable housing (this is for downtube shifters) the cable housing that is closest to the crank will not sit flush against the knob in the frame. You can see this in my photos that the cable housing just pushes straight up rather than running smoothly with the gear cable.

I haven't put the chain on yet, but you'll see that if the rear derailleur were in the same position without the wheel in place, the cable housing isn't sitting flush against the little knob where the housing is supposed to sit. On my other vintage bike they run fairly smoothly. I'm not sure what the issue is here and this is my first time building up a frame so help would be appreciated.

Could it be that the cable housing length is still too long? Is my cable tension not tight enough?

https://cimg8.ibsrv.net/gimg/bikefor...a0503dac0e.jpg
https://cimg9.ibsrv.net/gimg/bikefor...84bf958714.jpg
https://cimg6.ibsrv.net/gimg/bikefor...4301100ac1.jpg

You need a stepped ferrule.

Yep, you need a stepped ferrule to hold it in place. Is that brake or derailleur housing you're using?

Thanks, the answer was so simple.

I believe it's brake housing. Is there a difference if this is for downtube shifters? Should I be using derailleur housing?

Brake housing is wider and won't fit in the ferrule you need. Most brake housing also compresses more, but for non-indexed shifting that won't matter.

This is the ferrule you need for that cable stop: https://www.universalcycles.com/shop...&category=1613

https://www.universalcycles.com/imag...dium/62560.jpg

Or with the proper vintage housing, it'll porobably come with the right ferrule.

https://cdn.shopify.com/s/files/1/10..._1024x1024.jpg

And, you really do need derailleur housing!

Derailleur housing is significantly stiffer and will shift better. The stepped ferrule that you need is also usually made for 4mm derailleur hose, though sometimes 5mm can be found.

These don't traditionally play very well with indexed shifting :-(

alternatively you could just use a cable tie along the chainstay to hold it straight and remove the too big ferrule

I suspect that the doll's head cable stop will require a ferrule somewhat smaller than 4mm.

Top

Don't take the ziptie shortcut. Get the proper ferrule and the proper rear derailleur housing, and do the job right. Don't use that coiled housing.

It will only cost you a few cents do do the job correctly.

Yeah, I had a slew of stepper ferrules in my stash of parts but had to seek out one that was "skinnier" for the KHS Aero Comp.

https://cimg0.ibsrv.net/gimg/bikefor...3ed7c052f7.jpg
Found it on Ebay....I think.

I use "coiled" RD cable housing for most of my bikes and do not have any problems with them, plus they look great on a C&V bike.

A small point: bikes older than about 1985 probably used 5mm 'brake' outer for the shift cables.

I tried Shimano shift cables on my 1982 Holdsworth and the outer kept pushing through the cable stop (same position as OP one), then I worked out it was meant to take a 5mm outer since SIS wasn't invented for another few years.

As noted by JSL above, the compression that comes from coiled cable housing doesn't play well with SIS shifting. That's an SIS derailleur, but if he's using friction shifters, than the coiled housing is OK.

I have used a cable tie to good effect on one bike where the stepped ferrule or any other ferrule and any type of housing just wouldn't run very smoothly.

I call these "diver helmet" stops. I have this on one of my bikes, and when i was switching part, I set the special ferrule aside so aas not to lose it... of course I lost it. any one have a supplier for these special ferrules?

Sure, you can do it, and I'm sure it would be effective. You can also use duct tape for the same purpose. Or glue even. But assuming that cable stop isn't damaged beyond use, I'd try to avoid using things like zip ties or duct tape, and just assemble everything the way it was meant to be assembled. But again, this is just me..

Get the chain on to length to assess the loop size.
needs to be fair but not clownish.
I agree a stepped furrel is required
the pre crimped end on the current assembly may need to be cut off, in extreme cases the vinyl coating trimmed back to fit.

we called them Diver's Helmet stops, Campagnolo came up with them.

of course one has to be old enough to recall Diver Dan

I can see the likeness to a diver's helmet; we just called them cable stops.

I *think* Jagwire makes stepped ferrules?

Just do it right. A little Harbor Freight torch and a pinch of silver solder with flux and done.

https://cimg6.ibsrv.net/gimg/bikefor...9e8c5f3f46.png
Brazeons

Mine gets transferred between housing as well. Not sure how many times I've used the one in my current diver helmet stop.

I bought a handful from Velo Orange a few months ago, and it looks like they're still in stock: https://velo-orange.com/collections/...cap-5mm-to-4mm

EDIT: I have a similar diver helmet stop on my Eisentraut, and I am fairly certain I tried one of these ferrules in the stop after I repainted the frame to ensure I hadn't gummed up the works. I would do it again to validate, but right now I need to find the bag of ferrules again within my, ahem, "active project" space.