# tech question: madone rear brake cable routing



## MANTEIGA (Sep 26, 2008)

when i manually pinch my rear brake caliper together causing the cable to slack up....
i hear a knock coming from somewhere in the top tube....(slack metal cable hitting cf from inside, due to no outward tension from brake levers) it;s pretty loud so im sure its not cable housing hitting the inside..

this has lead me to believe that since the cable is fed through the actual top tube for whatever reason.... that the black plastic cable housing isn;t and just ends and the point where it enters... and where it comes out....?

what im getting at is how the hell am i going to replace the rear cable if i need to?
has anyone had to do this yet? is there an internal routing system built into the top tube (lol)
wtf?

or maybe the noise is something else.?


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## zac (Aug 5, 2005)

1) Correct, the cable housing does not run through the TT. It terminates at the front grommet, and a short piece then covers the rear section from the rear grommet to the barrel adjuster on the caliper.

2) Before you pull/remove the cable from the frame run a piece of liner around the cable and through the TT and out the front grommet. Then pull the cable leaving the liner in place. Alternately, the rear grommet is held in place by a small hex bolt. You can remove the rear grommet by loosening this bolt and then feed the new cable into the frame. Hook the end with a bent paper clip or a small pair of needle-nose pliers, and pull it out of the frame. Feed it through the grommet again, and replace the grommet.

HTH
zac


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## MANTEIGA (Sep 26, 2008)

*thanks zac*



zac said:


> 1) Correct, the cable housing does not run through the TT. It terminates at the front grommet, and a short piece then covers the rear section from the rear grommet to the barrel adjuster on the caliper.
> 
> 2) Before you pull/remove the cable from the frame run a piece of liner around the cable and through the TT and out the front grommet. Then pull the cable leaving the liner in place. Alternately, the rear grommet is held in place by a small hex bolt. You can remove the rear grommet by loosening this bolt and then feed the new cable into the frame. Hook the end with a bent paper clip or a small pair of needle-nose pliers, and pull it out of the frame. Feed it through the grommet again, and replace the grommet.
> 
> ...


----------------------------------------------------

you my friend....
are a genius!


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## JoeyBuck (Apr 2, 2008)

Zac,
I finally trimmed off the excessively long shift cables on my Madone last night. Sure wish I had some "liner". What do you use? The outer cable housings are obviously too big.


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## zac (Aug 5, 2005)

JoeyBuck said:


> Zac,
> I finally trimmed off the excessively long shift cables on my Madone last night. Sure wish I had some "liner". What do you use? The outer cable housings are obviously too big.


Well mostly I use some carefully chosen expletives, and while that doesn't really help at all, it makes me feel better 

Seriously though, if you don't have liner, and don't have the patience to fish the cable out of the other hole...take some string and before you pull the cable, wrap it around the cable a bunch of times and tie it off. Pull the cable and you have a feed string ready to go back through. On the return trip, again wrap the cable (if you know how to tie a fishermans knot use something like that, but wrap the cable an extra few times so the string doesn't pull off. Also a couple of wraps of electrical tape will help keeping the cable end from snagging on the inside of the frame.

zac


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## zac (Aug 5, 2005)

MANTEIGA said:


> ----------------------------------------------------
> 
> you my friend....
> are a genius!


The liner method is not my idea. I either tend to forget to feed the liner through when I break down my bike (When I pull cables, I am stripping the frame too), or if I remember, the liner gets loose and during my work on the bike. May be a good idea to tape the ends off so it doesn't fall out, or worse, into the frame completely. 

To be fair, the rear brake cable is very easy to fish out of the rear grommet hole with the grommet removed. The real *****y one is the other one...the front derailer cable feed through the BB shell.

zac


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## Exocet (Aug 27, 2009)

Hi Zac

When removing the rear brake cable, do you have to cut off the metal end cap first?
Many thanks
exocet

ps I found you photos of BB bearing removal invaluable thanks. Having had a slightly loose bearing which they tried to rectify with a shim, trek finally agreed to a frame replacement. Hence the stripping down of the bike!


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## zac (Aug 5, 2005)

Exocet said:


> Hi Zac
> 
> When removing the rear brake cable, do you have to cut off the metal end cap first?
> Many thanks
> ...


Yes, I am assuming you mean the metal crimp that keeps the cable from fraying?

You can either cut that off, or if you are reusing the cable, just pull it off with some pliers (you may want to try to round it off a bit first) and save yourself a quarter inch of cable.

While you can pull the cable through after without removing the frame grommets, the reverse is not true. The rear grommet should be removed. The set screw oddly for that is not metric, but SAE, I think a 3/32" (2mm spins and 2.5mm doesn't fit.) Really I don't have any allen that fits it perfectly and the closest is the 3/32.

BTW, let your LBS do the frame swap, that should also be covered by the warranty work.


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## bobf (Apr 3, 2015)

zac said:


> While you can pull the cable through after without removing the frame grommets, the reverse is not true. The rear grommet should be removed. The set screw oddly for that is not metric, but SAE, I think a 3/32" (2mm spins and 2.5mm doesn't fit.) Really I don't have any allen that fits it perfectly and the closest is the 3/32.


My set screw is T08 Torx. Dunno if you risk stripping if you drive it with a 3/32" allen. Luckily it doesn't need a lot of tightening.


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## cxwrench (Nov 9, 2004)

bobf said:


> My set screw is T08 Torx. Dunno if you risk stripping if you drive it with a 3/32" allen. Luckily it doesn't need a lot of tightening.


Pretty sure these guys got the problem taken care of seeing how the last post in this thread was 6 years ago...


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