Bicycle Mechanics - GURU internal Cable routing - Rear Derailleur

Hey Guys,

I've heard a couple ideas out here to alleviate my problem with internal cable routing. I've got the front derailleur thru the downtube easy enough and out the tiny hole it comes out to attach onto the derailleur. The rear shifter goes down the same path, except on the right side of the frame. Coming out of the bottom bracket area (obviously with the crankset removed), but now I have to deal with routing that cable through the chain stay and out a tiny hole. Not to mention, there is a bend inside that chain stay. I find that out by routing the cable backwards (in through the chainstay and out through the bb).

I've heard of getting another cable to route to backwards meeting with the primary shifter cable and sodering the ends, then pulling it through. Another idea was to use some heat shrink material to really get it on there better.

The best idea would be to use a cable guide which is essentially a cable housing to guide the cable through. Not sure if anyone sells this. I've heard I can use (if I have any left) some shifter cable housing, cut around the housing, take off the strands and there is a small enough tubing inside I can use as a cable guide.

Any of you guys have experience with this? Or any bright ideas.

I've already tried the soder - doesn't work. Haven't tried heat shrink yet..

a couple of noticeably dim (20 watt) ideas. :)

i've never attempted what you are doing, but i might try Radio Shack or Ace Hardware's electrical connector section for something. there are many types of small squeeze-to-clamp-on wire to wire connectors the last time i looked. most of which could easily be modified by a pair of wire cutters and a pair of pliers.

...and maybe a brake cable-end crimp on doodad, with the closed end cut off, might make a simple, crimpable tube that might allow two derailleur cables to be joined temporarily.

i'm a little bit handicapped here in that i don't how big of a (forgive me) hole :eek: you have to work with.

The best idea would be to use a cable guide which is essentially a cable housing to guide the cable through. Not sure if anyone sells this. I've heard I can use (if I have any left) some shifter cable housing, cut around the housing, take off the strands and there is a small enough tubing inside I can use as a cable guide.

Cable liner is available separately if you think that would work. http://www.universalcycles.com/shopping/product_details.php?id=41902&category=7

Yeah, cable liner should work. If you go to a high end road bike/triathlon shop they should be likely to have some. I work at such a place, and often have to deal with the hell of internal cable routing. The Cannondale SuperSix Evo, for instance, ships with a piece of fiber tubing through the entire top tube, which, if you pull it out, screws you absolutely and completely. Not that that's happened to me... yet.

If you can't find any cable liner, you can try screwing around with a magnet, which is not that helpful, but is better than trying to thread it through unassisted.

Could you tie a piece of thread onto some cable and poke it back through the hole near the RD until it comes out the BB. Then tie this thread onto your new cable and pull the thread through.

You could use this together with some cable liner.

I tie a piece of small steel wire to the cable I'm removing and then use that to pull the new cable through. But it the cable is already out, that won't help.

I have heard of putting a thin string (like thread) in the hole and using compressed air to blow it through the frame and out the other hole. Then tie the cable to that and pull it through. I have never tried that.

Could you tie a piece of thread onto some cable and poke it back through the hole near the RD until it comes out the BB. Then tie this thread onto your new cable and pull the thread through.

You could use this together with some cable liner.

haha... why wouldn't you tie a piece of thread after you route the cable through the chain stay first until it comes out of the BB? And that is what I did - but the pink ribbon i used as thread is now possibly forever lost in that chain stay... *smacks self in head*

I might be able to get out with some compressed air cans... hopefully. I'll try the cable liner idea.

i am still laughing. i think my coworker is still swearing at the guru he did last year

haha... why wouldn't you tie a piece of thread after you route the cable through the chain stay first until it comes out of the BB?

Not following you there..

Doesn't matter how you do it...you just need to have a length of thread that goes from the bb down the chainstay and out the hole near the RD. It should be just a matter of pulling it though once you have secured it to the new cable although getting it out the hole will still take a little bit of manoeuvring.

That's how I did my internal cabling anyway...although I didn't have a curved chainstay.

If you really want to get that pink thread out you can use a vacuum cleaner to suck it out.

hmm.. well anyways, the surefire way i found out after playing with it was to use the cable liner inside shifter housing. It's so thin and the perfect cable guide to fish that cable perfectly. Had another similar problem with the rear brake routing. The cable just did not want to come out the frame. You would think GURU would have thought to make ramps for the cable to smooth out perfectly, but no... they need to manufacture something only experienced people know how to do... not to mention if you ever have to replace the cables, it'll be a pain to go thru the process.

Anyway, to get that brake cable out, my brother and I made a J-hook small enough to go in the opening, pulled the cable out slowly until it just cleared the J-hook, then pushed it carefully out. Note for rear brake cable routing - the housing must go thru the frame and no ferrules required for brake housing except @ the levers. Then after getting the cable out, you can just guide the housing thru easily. All I got left is the chain, bar tape (if i want), and adjusting the shifter limits. And THEN i can finally think about buying miscellaneous stuff like computers, powertap, carbon wheels, the list goes on.... sighs* At least I can finally ride it soon..