Is it better to use one long housing cable?

[pakcyclist]

I have a custom road bike equipped with a Rohloff.  Since my bike shop no longer works on them, I have to deal with the nightmare of replacing the cables.  (Take me about 4 - 6 hours total, as I end up ruining about a half dozen cables -- too long!  too short!  cable totally frayed after putting it in the housing cable! -- before FINALLY getting it (semi)correct.  Almost makes me want to go back to a traditional drivetrain.  My bike has the cable braze-ons at the top and bottom of the downtube.  Therefore, mine is set up like a traditional road bike with 2 sets of housing cables -- from the shifter to the top braze on, and from the bottom one to the gear box, with only the bare cables on the downtube.  I'm wondering if part of the reason I have so much trouble is because I'm doing that, rather than one long housing the entire way.  That won't look as clean, as I'd need to use zip ties to secure it, but could that make the installation (somewhat) easier?

[Danneaux]

I think your root problem is the cable fraying during installation. I have two suggestions that have worked well for me...

1) Cut your cables using clean, sharp cable cutters with V-shaped jaws.

2) Apply a drop of super glue (preferably beta-cyanoacrylate, the kind that shows bonding rubber or leather on the package...it handles surface contamination better than the standard kind in my experience) to the end and allow to dry completely.

These two steps almost completely eliminate the possibility of the cable end fraying and make the task so much simpler and faster.

As to your quesiton about one continuous run of housing vs open runs and cable stops...

One run of housing should make insertion for the cable easier to insert and it will eliminate some of the places where dirt and moisture can enter the housing segments.

I'd still want to use the v-cutters and super glue, though. It will pay off when it comes to secure the cable end.

Best, Dan.

[pakcyclist]

Thanks.  Might try that.  But wouldn't the glue make the cable a bit bigger, and, therefore harder to get in the housing?

[PH]

The only reason all derailleur bikes now have open runs of cable and more stops is because of the finicky nature of indexed shifting, prior to that, many would have enclosed cables. With a Rohloff, it'll make no difference, do whichever suits you and the bike.
What cables are you using?  Rohloff cables, and most of the alternatives, have sealed ends and there's no need to cut them before threading through the outer. If you're using something without, why? But if you already have them, then as Dan suggests, seal the ends. Also, the length isn't mm critical, you have the adjustment on the external box or the last stop on an internal shift. If you cut the outer a bit long, maybe an extra 2cm, you give yourself some extra leeway with the inner (Shortening the outer effectively lengthens the inner. Cutting the inner the right length shouldn't be an issue, it's only the exposed difference from the outer that matters.  For cutting the outer, I just measure it against the old one. The only awkward bit of changing cables is getting them wound the right way on the pulley, but even that just takes a bit of practice. 

[mickeg]

I agree with everything Dan said.

I sometimes wrap some tape around the inner cable before I cut it.  That reduces the chance that it frays.

I prefer the Sram cable cutters.  They work well on shift and brake cables, as well as outer housing.  I checked, SJS does not sell it with the SRAM logo, but it looks like this one with a different name on it.  Mine (Sram) has red handle, not yellow.  The awl in the handle is great for making sure the end of an outer  housing hole functions well after cutting it.
www.sjscycles.co.uk/tools/jagwire-pro-housing-cutter/

But SJS also have much cheaper cable cutters too.

I assume you are aware that Rohloff shifter cables use brake outer housing that is NOT compressionless outer housing.  No need to use the compressionless shifter housing that is sold for derailleur bikes.

I do not know why your frame would have two sets of cable stops on the downtube for a frame built for a Rohloff.  Perhaps the frame builder did not realize that Rohloff cables have to have some slack, that there is no reason to use bare cable along the downtube.  But for aesthetics, do it any way you want.

I have started using Dan's suggestion for superglue on the end of the cable to reduce fraying, that was a great idea.  But it has to harden before you use it, you do not want to accidently glue the cable tip to something.

If you use your bike for touring, it would be a good idea to make sure that both cables are exactly the same length, and cut a third cable to that length too in case you needed to replace a cable later on a tour.  If you already have a cable cut to correct length, it simplifies cable replacement.  That means that the outer housing length for both cables should be exactly the same too.

I see PH made some comments while I was writing mine, I agree with everything he said.