CrowSeph

I have an huge amount of derailleur cable housing.
but always i had to buy a different one since this one is not working properly.

basically the derailleur start working bad and then when i inspect closely the cable housing i see that metal little cables inside the cable housing itself came outside the housing itself, piercing the metal terminal itself and loosing his strenght.

can be the way i cut the cable? an be the wrong terminals? or the cable housing itself that sucks?

Schweinhund

pictures, lots of pictures.

CrowSeph

damn! i totally forgot and already trown the old ones away

freeranger

Use good quality cable housing, good cutters, ream the end and file the end to make sure there is no sharp edge left from cutting. Good info here: How to Size and Install Shift Cable Housing | Park Tool

bboy314

Make sure you’re using the right ferrules (end caps) for your shift housing. Sometimes using ferrules made for the wrong diameter or brake housing can cause this.

JohnDThompson 

Use a good quality cutter, grind the housing end flat, and open the liner with a sharpened spoke.

Schweinhund

I think, from the description, that you bought a roll of unlined housing. without pictures, it's hard to see....
Threads that require conjecture.

cyccommute 

From what you’ve described, I suspect it looks like this

IMG_1361 by Stuart Black, on Flickr

IMG_1362 by Stuart Black, on Flickr

There’s not much you can do about it. The rods in the housing has broken free of the cable cladding. Cutting it off doesn’t fix the problem as the rods are still free to move in the housing. Replacement is the only option.

As to what cause it, it’s hard to say. Some housing from the same roll is perfectly okay and some isn’t. Probably a quality issue during the manufacturing process.

CrowSeph

Exactly, that's how the turns out.
Looks like i have to throw away an entire roll

dedhed

Had the same issue on my moms walker brakes. Found a small washer to fit inside the ferrule

cyccommute 

I wouldn’t necessarily throw out the whole roll. Just replace the defective housing and see what happens. If it happens twice, then consider throwing out the roll.

CrowSeph

Tested it multiple time... So..

Iride01 

Perhaps you are making the bends in the cable housing too tight a radius along it's routing. And maybe using compressionless cable where it shouldn't be used.

KCT1986

Don't know what is actually happening with the OP's case, but in the pic above, it looks like the end cap is incorrect. Probably a brake housing end cap (5mm) with a larger exit hole. The housing was not centered and some of the strand ends were pushed out of the hole.

As for the OP, try the housing with some alloy 4mm caps to determine if it's bad.

cyccommute 

The cap is the right size. It’s a 4mm cap. It’s distorted a bit from curve of the cable. The problem isn’t with the ferrule, however. I’ve seen this on a number of different cable housings with a variety of different ferrules.

KCT1986

That cap is loose. No way it's helping to support the structure of the outer coating.

Picture brightened.

Crankycrank

One thing that can help just a little bit is to cut the cable when it has similar curves in it as when it's installed. The strands on the outer radius have to travel further and if cut when straightened out somewhat this will cause the strands to become uneven in a shorter time.

Kontact

That is a brake ferrule intended for 5mm housing, not the OP's 4mm shift housing.

Take any shift housing of that type and bend curves into it and the difference in stretch between plastic and metal will cause the wires to stick out like that after a few days. If they are controlled by the correct ferrule it really isn't a problem. But when you are doing maintenance you can simply trim off those wire ends and put the (correct) ferrule back on. After that it shouldn't happen again because the outer plastic isn't going to keep shrinking.

dsbrantjr

I use this technique too, it is described in this article, in the "Index-compatible housing" section: https://sheldonbrown.com/cable-installation.html

cyccommute 

I don’t use oversized ferrules. That cable is from a Ultegra STI shifter (old style that comes out of the side of the lever) that won’t fit a 5mm ferrule. I may have grabbed a 5 mm ferrule for demonstration purposes. It’s been a long time since I took that photo for demonstration purpose. But I do use the proper sized ferrules on all my cables.

That would imply that we should see this kind of issue all the time. We don’t. Even on severely bent cable housing, this is a rare phenomenon. It happens but not on all housing.

I disagree on all counts. I’ve seen this often (but not all the time) on bikes with the proper ferrules…both metal and plastic. I’ve also seen housing where the plastic pulls back like this




For a very long time, I thought it was something done by the bicycle manufacturers during building. I couldn’t figure out why they had done that. It wasn’t until I noticed it on one of my own bikes that I realized that the plastic cladding is shrinking…probably due to heat. However, as you can see in the picture, the ends of the rods are still straight, unlike the red cable housing I posted above. I don’t know how much the plastic housing will shrink but I really doubt that the about 4mm and the 4mm at the other end is the extent of shrinkage. In other words, trimming the ends is only a temporary fix.

On the red housing…and similar housings where the rods come loose…the rods aren’t anchored and are free to move as pressure is put on the cable housing. The end of the loose rods can be pulled out of the housing with a pair of pliers as they aren’t anchored anymore. Basically, loose rods are not a fixable problem. And they are not due to anything we the consumer have done.

Kontact

I was speaking of the wire ends sticking out over time . I don't think there is a special problem with loose vs. tight inner wires - the loose one just do what comes naturally when you bend wire housing around a curve - the inside wires want to stick out and the outside want to retract. I haven't seen a problem with this happening that wasn't fixed by trimming the long ones - they can't keep growing.

While you may have slipped on a brake ferrule just to demonstrate, that's exactly what the OP is describing. 4mm shift housing ferrules are either thick brass or plastic, not the thin metal the OPS describes being pierced by the wires. He needs to trim the housing and then insert it into proper ferrule to prevent reoccurrence that turning the handlebar tends to allow.

cyccommute 

I’ve seen ones that “keep growing”. My example is a minor version of what I’ve seen. I’ve seen many where the inner rods extend 1/2” or more past the ferrule. The cable grabs the rods if they stick out far enough and pull them out of the plastic cladding. That’s the reason that I say this isn’t something that can be fixed by just trimming off the ends. The rods will continue to move.

Cable housing is cheap, so way bother with fixing it. Just replace the housing.

Kontact

How are they getting past 4mm ferrules? Sounds like a ferrule problem.

SurferRosa

^ This!!

cyccommute 

As the cladding shrinks back, the rods will bend inwards as pressure is applied. The inner cable then catches rods that are loose and pulls them through the ferrule. The hole on the ferrule doesn’t fit the inner cable tightly…it can’t and work properly. But it’s also not wide enough for the inner cable to pass smoothly through with one of the rods trapped in there as well. That causes the whole shifter to jam and not perform properly.

As I said before, I couldn’t figure out why the manufacturers were cutting back the ends of the cable housing until I observed that the cladding on my own housing had shrunk and that a rod had pulled through. I have experienced the rods pulling out of the housing without the shrinkage as well. Generally speaking, I don’t see this kind of problem with Shimano brand housing. It appears to be more of an issue with generic housing in my experience.