Author Topic: New cables- How often?  (Read 285 times)

Thomas777

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New cables- How often?
« on: May 11, 2018, 01:29:28 PM »
Wondering how often cables should be changed? My wife's bike has the Rohloff and we rode across Canada last Summer. This year we will be in Europe for 2 months.
Thoughts?
Thanks!

PH

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Re: New cables- How often?
« Reply #1 on: May 11, 2018, 02:13:48 PM »
Which type of shifter? 
If it's the internal mech, then it's something you really don't want to be doing at the side of the road, I used to change mine every other year, about 10,000 miles.  By that time the old one showed signs of wear, but never looked like it might fail.  The cables from the shifter to the connectors would be changed at the same time, or maybe earlier if they started to feel rough.  The inners are standard and I bought a reel of outer which will last my lifetime, so it's a cheap job.  Often you don't realise the deterioration in shifting because it's  gradual, then notice the improvement afterwards and wish you'd done it sooner.
With the external mech, I'm less sure.  I had mine converted six months ago, I'll have a look at it and probably replace before next winter.  Although never desirable, failure wouldn't be such a big deal.  I'd expect to be able to get something workable even at the roadside.

mickeg

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Re: New cables- How often?
« Reply #2 on: May 11, 2018, 04:11:01 PM »
I have the EX box on my Nomad.  I changed the cables once, but only because I lengthened the outer housing when I moved the position of my shifter.  When I changed my inner cables, I found that the generic Shimano road shifter cables fit just fine.  Make sure you only use stainless, there are some cheap galvanized cables out there.

I never change cables by a calendar or by distance traveled.  Instead when I tour I carry a spare of each inner cable (one shifter, one brake) and a tiny little cable cutter.  The Rohloff EX box cable installation uses a 200mm tube to measure the cable length to cut off, I carry two 100mm plastic drinking straws in my spares kit on that bike, I also carry some electrical tape so I could tape them together.

The Rohloff cable is normally slack, not under tension.  I suspect that lengthens the life span.  When I shift, I am careful to not try to force things.  I suspect when I read of people that broke a shifter inner cable that they hit the stop and then pushed harder, that I never do.

I have never used a Rohloff that has the internal gear cable, thus you should rely on others for advice on that particular cable, if they suggest replacing it on a schedule then perhaps that cable is one where you should?

The last cable that failed on me, was on a bar end shifter.  When I had to adjust by cable adjuster a couple times within 20 miles, I knew something was up.  And then when the broken wires started stabbing me (bar end shifter, the fingers are very close to the cable), then I knew something was up.  I changed the cable when I still had three unbroken strands, thus I still had the ability to shift until I got home and changed it.  I just checked the photo, I took that in 2012 so I have not had a cable fail for six years.


PH

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Re: New cables- How often?
« Reply #3 on: May 11, 2018, 04:35:02 PM »
From pg 24 of Living with a Rohloff
Quote
Please note that the internal gear wire will
snap eventually.
----Snip-----
But prevention is much better than cure, so why not consider
maintaining the cable in the same way that you would the cam
belt in your car? That is, change it at regular intervals, these
intervals being shorter than the service life of the component.
I believe that, because our cycles have such a perfect line of entry
of the cable into the hub, the cable should fail at the upper end of
Rohloff’s 10,000-30,000Km projected cable service life... so
20,000Km service intervals should see very few, if any, of our
customers with broken cables.
To those poor, unfortunate individuals who always seem to have
bad luck with mechanical things, I would suggest that, even if you
changed it at 10,000km (i.e. every other oil change) it would require
but a fraction of your time spent in maintenance compared to a
derailleur system.
http://www.sjscycles.com/thornpdf/ThornLivingWithARohloff_LoRes.pdf

geocycle

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Re: New cables- How often?
« Reply #4 on: May 11, 2018, 05:03:16 PM »
Definitely replace the internal hub cable on a precautionary basis.  As PH says it is a PITA to do at the roadside.  I've done mine three times in something over 35,000 miles, once due to a failure, twice as a precaution.  I think I've only replaced the shifter cables twice, once due to a failure where the cable frayed in the shifter.  The shifter cable is much easier and it was possible to limp home ok. Hope this gives an idea of the frequency.  If I were setting off around the world I'd replace both in advance and carry a built up inner as a spare.
 

Andre Jute

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Re: New cables- How often?
« Reply #5 on: May 12, 2018, 01:15:55 AM »
Just a reminder. Besides more logical design, the EX box has one great advantage over the open-cable "internal" setup: You can shift it manually even in the absence of cables by undoing the thumbscrew, pulling off the klickbox, and turning the central brass nut with an 8mm spanner to some all-purpose gear that will at least get you to the nearest bike shop or your hotel or home. That is why in toolkit discussions I recommended either
-- the X-Tools 14-tool multitool that has an 8mm socket in unit with a male hex stud, so it fits in the handle the same way as all the other bits in the set. You can see it here (sorry, the only photo I could find) http://www.bikesweets.com/XTools_14_Bit_MultTool_p/xtools-multi-tool.htm
where the second photo shows the 8mm socket on a stalk at the bottom corner on the left. (The thingy in the middle of the bits that looks like it could be a socket is the driver extension unit. The 8mm socket is the shallow one, lower left; you can't see the stalk because it is in its retainer slot.) I bought this whole set, water damaged, from when Chainreactioncycles, who're up the road from me, had a flood, for two euro merely to get this odd 8mm socket, because I had a much more elegant and much lighter multitool already. But all this sturdy kit requires to be suitable for a Rohloff owner's on-bike kit is a good quality T20 Torx bit, which can fit in the space where you've removed a bit that is irrelevant to your bike.
-- or a Draper 8x10mm flat cyclist's brake spanner
-- or a common car 8x10 brake spanner from any motor factor's, ground down flat to save weight
-- or a good quality (it's a nut you really don't want to round off!) 8mm socket plus a 1/4in by 6mm hex bit so you can drive it with your multitool.

***
Rewiring the EX box is almost as odious a job as rewiring the internal routing, just slightly less tedious. You still have the same problem that every time you get it wrong, you can't reuse the wire, or any of the fiddly bits, so you'd better have spare cables and fiddly bits at the outset, before you start. I seem to remember that the advice a few years ago was to practice recabling at home if you've never done it before... The word "odious" above comes courtesy of Chalo Colina, who, hint, hint, is nobody's novice bike mechanic.

It is therefore just as well to know that the Rohloff cables can stand up to a lot of abuse. Mine have been stressed for over 10K by raising the handlebars about three inches since the cables were cut to fit tightly, and I haven't replaced them, though I have spares, because my health doesn't permit me to bend over the bike for long. That's probably also a reason to use the official Rohloff cable set, rather than cheap rubbish that you can't discover is cheap rubbish until the postman drops it off. The Rohloff sets are cheap enough by comparison with roadie kits from the boutique suppliers.

***
If those of you of a theoretical bent are looking for something more interesting than counting sheep while you wait for sleep, consider this question that the discussion gives rise to:

Why is it that Bowden cables are not damaged by being push-pull when the pull-pull action of the Rohloff twin-cable system is clearly superior?
« Last Edit: May 12, 2018, 01:21:55 AM by Andre Jute »

Danneaux

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Re: New cables- How often?
« Reply #6 on: May 12, 2018, 02:51:06 AM »
Quote
Why is it that Bowden cables are not damaged by being push-pull when the pull-pull action of the Rohloff twin-cable system is clearly superior?
If i understand your question correctly...

Derailleur Bowden cables are not actually push-pull, but pull-pull because the mech's return spring provides tension when the shift lever is not pulling.

During a shift, the single cable operating the derailleur very briefly goes briefly slack until the chain can shift to the next cog, but the cable never actually pushes so no damage occurs.

All the best,

Dan.

PH

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Re: New cables- How often?
« Reply #7 on: May 12, 2018, 03:34:51 AM »
Why is it that Bowden cables are not damaged by being push-pull when the pull-pull action of the Rohloff twin-cable system is clearly superior?
Well, they're both Bowden cables and they're both subject to wear at any point they move through a tight radius.
Campag gear cables are notorious for fraying and jamming the shifter, they can be a real pain to remove. I've done it once and that was once too often -  mine get changed at the same sort of mileage as the Rohloff ones.
As we're in the realms of theory - how do you push something with a cable? 

Andre Jute

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Re: New cables- How often?
« Reply #8 on: May 12, 2018, 07:40:10 AM »
As we're in the realms of theory - how do you push something with a cable?

No problem. You make the cable very thick and very short and consequently very stiff. Drop into any port to see the size of cable I'm talking about.

Of course, if you delimit the question by some qualification such as "on a bicycle", you can route the far end of the cable to far side of the object to be pushed, and the pull then becomes, from your viewpoint in  front of the object, a push. Or Dan has given us another answer: You springload the thin, long cable on the nominally push phase so that the push on that phase becomes effectively a pull.
« Last Edit: May 12, 2018, 11:09:50 PM by Andre Jute »

PH

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Re: New cables- How often?
« Reply #9 on: May 12, 2018, 12:20:03 PM »
Drop into any port to see the size of cable I'm talking about.
Going completely off topic - I now have a desire to ride to a port, not specifically to see cables, but simply because it's decades since I've been to one that wasn't just a ferry terminal.

John Saxby

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Re: New cables- How often?
« Reply #10 on: May 12, 2018, 02:06:34 PM »
Ports have their own magic, for sure, and well worth a visit, even tho' hempen hawsers are hard to find these days. 

OTOH, if not nearly so intriguing, one can just grab something like my Krypto-flex lock cable, a mere 6mm encased in clear plastic. It scores quite well on the Pushability Index--slides along the floor, doesn't get bent out of shape when pushed. Then again, it wouldn't work very well as a control cable on my Raven.   

Tigerbiten

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Re: New cables- How often?
« Reply #11 on: May 12, 2018, 05:49:03 PM »
I do mine at least once a year, it all depends how often I cycle in the rain.
On my recumbent trike my handlebars are vertical.
This means rain tends to wash salt/grit into the cable.
The more often contaminates are washed into the cable, the quicker they fail.
I also have this type of trouble with my hydraulic brakes and the main piston seal.