Bicycle Mechanics - shifter cable question

Hi all,

I’m having a little trouble changing the shifter cables on my bike.

I changed the front derailleur cable recently. Shifted to the small gear, removed the old cable, and threaded the new one through the right holes and guides. Cut the new housing to the same length as the old. I think I have all this right.

The problem came when I fastened the cable to the derailleur. I pulled the cable taut and tightened the clamp, and then turned the cranks to run through the gears. The derailleur wouldn’t move the chain from the middle to the big gear (it’s a triple chainring). Cable tension seemed a little loose, so I went to tighten it. That was when I noticed that the cable was already beginning to fray at the point where I’d attached it to the clamp.

Removed the cable, tried another one. Same thing happened.

Obviously I’m doing something wrong.

Would over-tightening the clamp cause immediate fray to a new cable? Or maybe I’ve attached it wrong: there’s an outer part of the clamp, then a washer, and then the part I think of as the clamp’s base, against the derailleur itself. I had the cable between the washer and the base. Should it be between the washer and the outer part?

I don’t know how well I’ve described this. And I don't know what the heck I'm doing wrong. Have checked the Sheldon Brown page but not found an answer. Any suggestions?

The cable fits between the washer and the derailleur (not between the washer and the attachment bolt). If you look closely you will probably find a small indent/groove the cables will rest in. If you leave the cables untrimmed until you have finished your adjustment, you can avoid the premature fraying of the cable. (Also, don't over tighten the attachment bolt. It takes far less pressure than you might imagine just to hold the cables when you're making adjustments.)

There is a small "tab" outside of the cable fixing bolt. The cable has to be routed OVER this tab and then to the clamping bolt. It must not go between this tab and the bolt.

Is this correct? This is a FD setup that runs along the top of the top tube and then down the seat tube. I saw that tab thingy on my FD and couldn't figure out what to do with it. I'd seen posts here saying the cable is supposed to loop around it some way, but I don't think I understand exactly how.

281614

At least the cable is between the washer and the derailleur body? Someone wanna explain or draw a line on my photo showing which route the cable is supposed to be taking?

Well, your setup is a bit different, being a top pull. However, I believe you have the cable run backwards, that is the tag end should be to the outside of the bolt and the long run from the top tube should be inside of it. The way you have it reduces the derailleur travel and explains why you can't shift to the big ring. Overtightening the clamp bolt won't help or hinder shifting but it does crush the cable unnecessarily.

Thank you for the help, by the way. I am not the OP, and I can get my FD to the big chainring. I just always had a couple weird questions about my FD setup.



...the tag end...
Uh, just to make sure I have my terminology right, the tag end is the end with the little pinch cap thingy you put on?



...being a top pull... I believe you have the cable run backwards, that is the tag end should be to the outside of the bolt and the long run from the top tube should be inside of it.
I'm sorry, I just want to make sure I understand correctly. Should it be like this?

281753

Would that be right? And if so, what exactly is the point of the tab on the FD? It wouldn't seem to be articulating with the cable at all.

I'll have to admit I'm not familiar with the exact cable routing on that derailleur, and is appears to be a very early top pull, so not much to find in the way of examples on the web. I thought otherwise at first but looking closer at the 2nd pic it appears that routing would be correct. Make sure you have the cable positioned so as to be in the groove in either the washer or the derailleur face. Do not wrap the cable around the bolt/washer. Route it just to the one side, straight through, and then tighten. After the bolt is tightened you can bend the end of the cable inward. Wrapping it around actually provides a less secure mounting in addition to distorting the cable more.

Thank you for the help, by the way. I am not the OP, and I can get my FD to the big chainring. I just always had a couple weird questions about my FD setup.



Uh, just to make sure I have my terminology right, the tag end is the end with the little pinch cap thingy you put on?



I'm sorry, I just want to make sure I understand correctly. Should it be like this?

281753
.

Would that be right? And if so, what exactly is the point of the tab on the FD? It wouldn't seem to be articulating with the cable at all.
Yes to both questions. The tab next to the clamping bolt is used as a cable guide with the more common bottom pull cable routing.

Also, cny-bikeman's recommendation to run the cable through in one direction only is a good one. cut off the excess and recap it.