Author Topic: Replacing Rohloff shifter cables...  (Read 6490 times)

rafiki

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Replacing Rohloff shifter cables...
« on: February 03, 2019, 12:37:43 pm »
Another job on my to-do list. I have the external mech. The process is well documented but I just wanted to ask: how difficult is it in practice to wind the cables onto the ex box pulley? It looks a bit fiddly. Any tips?
Brian.

mickeg

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Re: Replacing Rohloff shifter cables...
« Reply #1 on: February 03, 2019, 02:07:27 pm »
You will need a T20 wrench to open it up.  I think that some have had problems with dissimilar metal corrosion on the threads and had trouble getting the bolts out.  It might be useful to just check to see if they will unthread ok before you start so you know in advance if that will be a problem.

The cable end goes into a very small hole, you need a clean cut on the end of the cable to make sure that the cable can be inserted.  Thus a good cable cutter is needed to make a good cut.

I do not recall what wrench size the set screws take, but I did not need to go searching for a tool so it probably is a common size on a good multi-tool.

Keep track of which cable is which.  On one or maybe two occasions my first gear was gear 14 on the shifter.  Thus, I had to switch cables.

And put a bit of grease into the box when you are done.

I do not recall if I put any loctite on the bolt threads that hold the box together or not, but I might have done so to reduce the potential for dissimilar metal corrosion.

rafiki

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Re: Replacing Rohloff shifter cables...
« Reply #2 on: February 03, 2019, 05:16:49 pm »
Thank you. Good points, especially about checking that the box can be opened before committing. I just checked my torx screws and they are free. Much appreciated. Do you find winding the cables around the pulley easy?
Brian.

mickeg

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Re: Replacing Rohloff shifter cables...
« Reply #3 on: February 03, 2019, 05:56:51 pm »
I had no problem with winding the cables on the pulley wheel.  I probably turned in my adjustment screws so that I had excess cable to play with.  Since I put some grease in the box, the parts were rather greasy so things likely slipped out of my fingers a few times.  But I probably spent no more than a couple minutes doing it.

I used a plastic drinking straw cut to the right length (is it 200mm?) for my cutting guide, did not buy the metal tube that is sold for that.

If you are still unsure, you could check and see if there are any youtube videos that show it.

I always forget to leave my shifter in gear one or 14 before I remove my box from teh hub, but the first thing you might want to do is know what gear your hub is in before you start.


rafiki

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Re: Replacing Rohloff shifter cables...
« Reply #4 on: February 04, 2019, 12:34:40 pm »
The Rohloff video shows the winding around the pulley and it doesn't look too difficult. The Rohloff manual suggests slipping the pulley onto an Allen key to support it whilst winding. The reason I asked is I recall some comments on another thread, that I can't find now, which led me to believe it was a tricky operation. I appreciate those further tips. Thanks.
Brian.

Andre Jute

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Re: Replacing Rohloff shifter cables...
« Reply #5 on: February 04, 2019, 07:15:40 pm »
This may be what you're looking for:
http://thorncyclesforum.co.uk/index.php?topic=2676.msg12897#msg12897

I'll reprint it in full below. Chalo Colina is a famous Boeing toolmaker who now builds circus bikes; he was into Rohloffs from the beginning, well before most of us, and owns several Rohloffs with serious miles on them; the well-known Aaron's 48 spoke Rohloff sometimes used on tandems is built to his design (he weighs 350 pounds after a strict diet). Pete Cresswell was once a member here, years ago. The exchange happened on RBT in its high days, when Sheldon Brown and Jobst Brandt were still alive.
***
***
Reprinted from RBT. The respondent, Chalo Colina, is a machinist, bicycle mechanic and builder of circus bikes; he owns several Rohloff gearboxes.

***

Andre Jute wrote:
>
> While I'm ordering service/spare parts and tools for the first annual
> service of my Utopia Kranich and its Rohloff gearbox at about 2000km,
> do I need to order spare gear cables for my EXT klickbox, either for a
> routine swap-out or to keep on standby for a likely breakage. I note
> that Andy Blance of Thorn reckons that even the dicier internal cable
> setup is very unlikely to break before 10K.
>
> Blance also says the EXT gearbox cable on the Rohloff is standard
> dimension normal brake cable. (The internal cable is apparently
> thinner.) Has anyone used standard brake cable, outer and lining
> instead of the Rohloff's own supply? With what result?

Rohloff's external clickbox and shifter are wired with two totally
normal 1.2mm shift cables.  You don't have to stock special spares for
that job.  Depending on your setup, you might need tandem-length
cables.  A quick survey with a tailor's tape measure will tell you if
you need to keep some extra-long cables handy; normal shift cables are
2.0m long.

Rewiring a Rohloff shifter is an _odious_ job, though.  You have to
get a whole series of operations exactly right, in the right order,
before you fasten the cables down.  The cables are fastened with grub
screws, and once tightened even lightly, they can't be reinserted into
the clickbox drum again.  So if you forget any detail in the cable
component stack or in the routing of the cable, you have to begin
again with new cables, starting at the shifter spool.  I think the
most times I have had to do this at one sitting is four times in a
row.  (It's not just outright mistakes that can stop the show.  If it
doesn't feel quite right and you want to try changing something, you
have to start over from step one.)

When the time comes to replace Rohloff shift cables, have every single
bit ready in advance.  Have every tool available that you might want--
bench grinder, fourth hand, precision ruler, whatever.  Have the
printed instruction sheet in hand and refer to it at every step.  Do
not reuse a single piece of housing or ferrule, lest this seemingly
sensible and economical measure require you to repeat the job.

But hey-- at least it uses standard cables.

Chalo

***

And here's another owner of multiple Rohloffs, Pete Creswell, in the same RBT thread with more good advice about measuring the cable:

***
   
Per Andre Jute:
>Thanks, Chalo. I've saved this post. From the video on the Rohloff
>site I thought it looked like a tricky job -- and remembered that
>before this you described it as "odious"

I'll concur with "odious".

For me the recurring problem was getting the length of cable that
protrudes past the housing exactly right.

To that end, I cut a piece of housing to exactly the right
length.

I've done several replacements with the housing piece as my
length guide and haven't had any problems.

But I still have a half-dozen shift cables ready just in case
when I start the job.

Pete Cresswell

***
[This is me again, addressing the OP of the thread in which this post originally appeared:]

I assume you already have:

Rohloff cables explained -- Andy Blance Nov 2005, PDF from Thorn site
Cable changing video -- movie from Rohloff site

HTH. Good luck.

Andre Jute

rafiki

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Re: Replacing Rohloff shifter cables...
« Reply #6 on: February 04, 2019, 09:26:21 pm »
Thanks Andre. I guess I'd better order up a few more cables before I make my attempt.
Brian.

Danneaux

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Re: Replacing Rohloff shifter cables...
« Reply #7 on: February 05, 2019, 12:27:29 am »
I found it an easy job, helped by first applying a small drop of beta-cyanoacrylate ("super" super glue) to the ends of the freshly cut cables so they didn't splay out when clamping. Be sure to quickly wipe off any excess and let the glue dry before proceeding. I have yet to break a cable in use; my replacement came early on when re-routing the housings to accommodate a new configuration.

I also found it helpful to fill my external shift-box with Phil waterproof grease. See:
http://thorncyclesforum.co.uk/index.php?topic=4523.msg36175#msg36175
...and...
http://thorncyclesforum.co.uk/index.php?topic=4523.msg95429#msg95429

I would caution against using a heavier grease; the Phil stuff turns to oil at the working surface to provide lubrication and prevent galling while maintaining a grease seal at the edges to prevent water, dirt, and dust entry.

When touring, I pack a small brass tube pre-cut to size so I can accurately measure and cut the cables for a field replacement if necessary.

Best,

Dan.

rafiki

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Re: Replacing Rohloff shifter cables...
« Reply #8 on: February 05, 2019, 06:22:42 am »
Thanks Dan. Great tip about the superglue. Is that a special variation of superglue or the regular industrial stuff?
Brian.

mickeg

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Re: Replacing Rohloff shifter cables...
« Reply #9 on: February 05, 2019, 05:14:47 pm »
I found it an easy job, helped by first applying a small drop of beta-cyanoacrylate ("super" super glue) to the ends of the freshly cut cables so they didn't splay out when clamping. ...

I also found it helpful to fill my external shift-box with Phil waterproof grease. ...

When touring, I pack a small brass tube pre-cut to size so I can accurately measure and cut the cables for a field replacement if necessary.
...

The Superglue is a great idea.  I have never used Superglue after hearing too many stories of people gluing fingers together or other such stories.  But I am now tempted to give it a try.  I need to pick up some Superglue next time I am in Dollar Tree.

I just put enough grease in the box to make sure that there is no metal on metal rubbing without lubricant.  But filling the box certainly won't hurt.

I carry two 100mm plastic drinking straws for the purpose.  I have not tried to use them to cut a cable but since they are the same diameters they should not telescope, so probably do not need to tape together.  The reason I carry two shorter straws instead of a long one is that my tool bag is shorter than 200mm.

All of your points are good points.


Danneaux

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Re: Replacing Rohloff shifter cables...
« Reply #10 on: February 05, 2019, 05:33:58 pm »
Quote
Is that a special variation of superglue
Ethyl cis-beta-cyanoacrylate is a variation that is not always listed by name on the consumer packaging. Quickest way to tell is to look for mention that it will also glue rubber and wood.

I prefer this one: http://m.loctiteproducts.com/p/4/0/2/sg_ul_cntrl/Loctite-Super-Glue-ULTRA-Liquid-Control

It also glues fingers really well, so it is wise/convenient to wear some disposable gloves while applying it. Eye protection is also good, as I learned firsthand when the packaging failed.

Best,

Dan.

John Saxby

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Re: Replacing Rohloff shifter cables...
« Reply #11 on: February 05, 2019, 05:35:04 pm »
On the superglue, George:  I always use lightweight mechanic's/doctor's/etc gloves.


mickeg

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Re: Replacing Rohloff shifter cables...
« Reply #12 on: February 05, 2019, 05:42:06 pm »
On the superglue, George:  I always use lightweight mechanic's/doctor's/etc gloves.

Thanks.  I keep a small supply that I partially replenish each time I visit the dentist or doctor office.  But I mostly just use them for working around a chain or other messy project. 

I also keep a pair with my spare tube on the bike.

PH

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Re: Replacing Rohloff shifter cables...
« Reply #13 on: March 22, 2019, 01:12:37 am »
The cables are fastened with grub
screws, and once tightened even lightly, they can't be reinserted into
the clickbox drum again.  So if you forget any detail in the cable
component stack or in the routing of the cable, you have to begin
again with new cables, starting at the shifter spool.
While the inner cable protrusion needs to be a fairly precise length (There is a bit of leeway with the adjusters) the routing of the outer cable is fairly flexible.  if you've made a mess of the inner cable end, then cutting say 5mm off both the inner and outer brings you back to square one.