Answers: Threading a Derailleur Cable

Eureka. The rear derailleur cable is threaded. OK, thanks to great folks like Peter Westerholm and Skip Echert, I’ve think at least I have some strategies for getting the darn rear deraileur cable through a chain stay:

* Here is my technique. I noticed this rear derailleur cable is at the exact center of the stay. And that a stiff brake cable goes right through. I lifted the bike up so the stay was perfectly vertical. Dropped the cable in and voila it popped out. (See below for other methods suggested).
* Park Tools Info. It is best to use a wire that has been soldered, as it prevents fraying at the end. New cables are welded, and these will work as well. It is often a case a both luck and patience. Give a slight bend the the wire, and then feed in into the hole under the stay near the bb. Work the cable back and then begin tapping. Twist the wire as you tap and it should find the hole. Good luck. Calvin Jones. Park Tool
* “Peter Westerholm”:http://www.fixedgeargallery.com/westerholm.htm. Try very heavy Fishing Line or a light wire. First thread that trough front to back,You may need to use a needle hook to catch the Fishing line in the small exit hole. then run the Cable casing threaded through the starter line and then pull the Line out and run your gear cable. Or try to ask “Sheldon Brown”:http://www.sheldonbrown.com for his feedback. If he can not help then your screwed. Good luck Peter
* “Skip Eckart”:http://vintage-trek.com. Perhaps you can use a vacuum cleaner hose to suck a thin string or thread through the stay, while holding the bike vertically. Then tie the end of
the string to the cable and pull it through. Sorry that I don’t have the definitive answer. If you do get something to work, please let me know. You could post the question on the vintage light weight discussion list at “Vintage Lightweight Bikes Forum”:http://oldroads.com/d_ltw_def.asp?rec_count=1.
* Vintage Lightweight Bikes Forum”:http://oldroads.com/d_ltw_ra.asp?OQID=13500&QuestionNum=13500&RID=0. I have a 1987 Trek 560 and ran into the same problem. A friend of mine told me to try to run the cable housing through first and see if that does it. If not, run a scrap piece of cabling with a string attached to it. The idea is to run the scrap cable though the chain stay and pull it through to get to the string. Then attach the string to your new derailleur cable and pull it through that way. As long as the string and scrap cable is long enough, you shouldn’t have a problem. Good Luck Bryant. You also might try some mechanics wire or bailing wire. “Smitty”:http://oldroads.com/d_ltw_ra.asp?OQID=13500&QuestionNum=13530&RID=13501.

2 thoughts on “Answers: Threading a Derailleur Cable”

  1. I have a trek 400 from 1988 and tried a combination of your suggestions plus one idea I had. Since the bike was in storage, this was my first cable change since I bought it new. I also ended up taking it completely apart to clean and lube also. I positioned the bike frame (both wheels off) with the chainstay perfectly vertical, handlebar end up, and secured the bike. I used a larger size needle and a long thread(doubled) and was able to feed the needle and thread from the entry point all the way through to the drop out opening exit. Then I tied the thread to the derailleur cable end (freshly clipped) and as close to the end of the cable as possible. I slowly pulled on the thread at the same time hand feeding the cable into the chain stay opening of the frame near the bottom bracket. I used the thread to lightly guide the cable as far as it would go. I then lightly pushed the cable trying to align it, using the thread tension to center it, and on my second try, the cable finally fed through exit hole and now I am able to complete the set up. Thanks for your suggestions. One other note: This pertains to disassembly of the bottom bracket on my trek 400…the right hand “fixed cup” unscrews in a clockwise direction, which is contrary to logic. Just another unique feature of this bike.

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