Tips for replacing internally routed cables

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OhPinchy
Posts: 80
Joined: Wed Feb 27, 2013 5:38 pm

by OhPinchy

I've got a Dolan Scala TT bike with internally routed cables. Last time I had to replace a gear cable, it was just trial and error moving the cable around that got me there in the end, but it took a while - I ended up just using gravity and tilting the frame in various ways to get the cable to pop into sight and then used a tweezers to reach in and grab it.

I tried a strong magnet but it worked in the middle of the tube (could hear the cable snapping to the magnet) but where the carbon was thicker around the cable exit hole, it didn't work (or the cable got stuck against the edges of the exit hole internally). Check on youtube for tips and tried one where you get a cable end cap and cut a hole in it and then crimp one end of it to the existing cable and one end to some twine. Then pull the cable through the frame and then repeat the process joining the twine to the new cable and pulling that through. Tried it for both twine and dental floss and neither worked.

Seems the internals of the Dolan frame have fairly sharp corners so the cable doesn't easily find its way to the hole so needed some force and that meant the twine/floss came out from the cable cap. I've now got some nylon cable which I reckon might work better as the cable end cap can indent into it when crimped and should give a better hold and hopefully work.

Wanted to check if anyone had other tips that they've found work well?

by Weenie


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glepore
Posts: 1408
Joined: Thu Mar 28, 2013 4:42 pm
Location: Virginia USA

by glepore

can you route liner over the existing cable to its exit point from the frame, snip cable there and remove, leaving liner in place?
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OhPinchy
Posts: 80
Joined: Wed Feb 27, 2013 5:38 pm

by OhPinchy

glepore wrote:can you route liner over the existing cable to its exit point from the frame, snip cable there and remove, leaving liner in place?


Interesting idea, thanks. If I understand it, what you mean is: disconnect cable from rear derailleur, slide cable liner (I have plenty spare) over the cable up towards the front of the frame and leave some of it sticking out both holes at either end of the frame and then fit the new cable into that, and then slide it off when done routing the cable through it? Sounds like an elegant solution if so!

kode54
Posts: 3748
Joined: Tue May 23, 2006 9:39 pm

by kode54

you can use sewing thread...then tape all the open holes up with tape...use a vacuum cleaner and suck the thin thread through the hole you want. then tie and tape the end of the housing with he other end of the thread and pull through. simple and fast. sometimes, the tight bends will hang up the stiff housing, but if you taper the taped ends to be gradual...it should smooth over those bends.
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goodboyr
Posts: 1487
Joined: Wed Jan 10, 2007 10:56 pm
Location: Canada

by goodboyr

The new Park Tool IR-1 kit is your friend. I've used this successfully on a bunch of internal installs, and it makes the job super easy.

http://www.parktool.com/product/internal-cable-routing-kit-ir-1

glepore
Posts: 1408
Joined: Thu Mar 28, 2013 4:42 pm
Location: Virginia USA

by glepore

Yes, have done that in the shop. Its how some of these bikes are shipped.
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OhPinchy
Posts: 80
Joined: Wed Feb 27, 2013 5:38 pm

by OhPinchy

Tried sliding some spare cable outer over the in situ cable. Fed into the chainstay from the rear derailleur no problem, but got stuck around the bottom bracket area and no amount of wiggling would get it through. Hole at the front end behind the headset is reduced down to only allow a cable through, not a cable outer, so wouldn't work anyway.

Have tried the vacuum cleaner trick before and it didn't work, though maybe I hadn't made the frame airtight enough. Need to get this done tomorrow night to race later in the week, so will go back to my trial and error method if nothing else works quickly. Will give the nylon thread crimped to an end cap on the in situ cable a go.

grover
Posts: 1302
Joined: Mon Jul 26, 2004 1:06 pm

by grover

Don't use spare cable outer. It's too stiff hence getting caught on bends.

Use cable liner...

http://www.ebay.com.au/itm/Alligator-ca ... 0395976889

It's very flexible and just follows the inner cable smoothly. It is also very thin and will fit through the hole that is only designed for a cable to fit through.

Disconnect derailleur, slide cable LINER (not outer) onto shifter cable.
Pull shifter cable out of frame pulling liner through as well (be sure not to pull cable out of liner before liner comes out of frame up near bars)
Once liner is protruding from both ends of frame you can pull the cable out of it.
Install new cable in shifter, and outer that goes from shifter to frame onto new cable.
Slide new cable into liner protruding from frame, and all the way through out the other end with ease.
Once new cable is out the other end of frame you can pull the liner off.
Install outer from frame to derailleur as normal and tune gears.

drewb
Posts: 96
Joined: Tue Aug 24, 2010 11:53 pm

by drewb

Similar to the above... except I use electrical heat shrink.

Shrink a long piece of tueb to the end of the old cable. Pull the old cable all the way through- leaving the empty heat shrink tube to create a path for the new cable to be fed in a reverse direction. Soooo quick.

Radiokopf
Posts: 46
Joined: Sun Oct 27, 2013 10:54 am

by Radiokopf

drewb wrote:Similar to the above... except I use electrical heat shrink.

Shrink a long piece of tueb to the end of the old cable. Pull the old cable all the way through- leaving the empty heat shrink tube to create a path for the new cable to be fed in a reverse direction. Soooo quick.


+1


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2old4this
Posts: 366
Joined: Mon Jan 13, 2014 7:26 am

by 2old4this

It is a PITA to do full internal wiring on TTs. I've tried magnets and vacuuming and wiggling. Then,a friend recommended a fishing tool from HomeDepot (it is a HW store in the US.) It looks like this (though with much smaller head.) Priceless...

http://www.ebay.com/itm/Claw-Magnetic-P ... 65&vxp=mtr

OhPinchy
Posts: 80
Joined: Wed Feb 27, 2013 5:38 pm

by OhPinchy

Thanks for the tips. That fishing tool looks interesting, as does the heat shrink option though I don't currently have tools for that.

As I'm stuck for time, I'll try pick up a cable inner liner this afternoon, and revert to the wiggling it around till it eventually works method if my LBS doesn't have any of that for sale.

ourmanflint
Posts: 39
Joined: Mon Sep 08, 2014 4:12 pm

by ourmanflint

Use gravity!

Keep in and out vertical and thread something heavy enough and it will naturally fall downward. Have done a fair few frames this way and always seems to work pretty well

AJS914
Posts: 5397
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

I don't want to start another topic but just need to vent. I picked up a set of 3T Ergonova carbon bars. I didn't even realize they were internally routed until I unwrapped them. I bought them based on the bend and reach.

Internally routed is nice in theory but the installation is such a big #$%#@@@!!! PITA. It took me at least an hour just to get the right shift lever and cables in place. Now I have to do the left side. If I was going to do it over I think I'd just tape the cables under the bar.

Also, the sharp bends the cables make don't give me confidence that shifting will be super smooth. Similarly, I struggled with a set of Zipp Vuka Sprint bars a couple of years ago.

mariovalentim
Posts: 225
Joined: Fri Aug 28, 2015 2:03 am

by mariovalentim

I have a 3T Tornova and it wasn't that hard on my first try, obviously not like external routing but it was something like 15min....if I had to do the whole bike then I would DEFINITELY buy the park took internal routing kit

by Weenie


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