Airfehr

What is this coating on my derailleur cables? It's some kind of anti friction plastic only on the cables where they make a sharp bend at the bottom bracket. Not a housing liner as it's on the cable like a shrink tube and moves with the cable. The OD looks to be about 1.7 mm. Hard to read my calipers these days. I need longer cables to work with new bars and hate to have bare cable wearing through the plastic guide.

Andrew R Stewart 

These sure look like common cable liner to me. Can you reuse the sections? Can you get replacement lengths of the common liner to see if it will fit through the various ports and guides? Andy

Airfehr

It's not coming off the cable without a knife. Cable does not slide inside of it.

Andrew R Stewart 

Did you buy the bike new? Have the cables been replaced since the new sale? What brand/model? Is there a LBS involved?

What you describe is not common, a cable with a short section of some sort of low friction (plastic?) coating, only at the correct spot for this bike and it's size, that is adhered to the cable enough to require destructive removal, that happens to fit through the bike brand's cable pathways well enough to not snag on them. If all this is correct than I would consider these cables to be a OEM/specific to that bike design and spec. In which case the brand, one would assume easily, should have some obligation to provide these cables for their annual replacement for at least the duration of the frame warranty.

Or you have common cables that you don't fully understand the liner and cable relationship. Andy

Airfehr

I bought the bike used so the cables may not be original. Bike is a 2014 Giant Escape RX,
https://www.giant-bicycles.com/us/es...composite-2014
The plastic section would not have fit through the housing so I'm guessing it was applied like shrink tubing. It has a teflon greasy feel and not shrink tubing.

JoeTBM 

Are you sure they are not Teflon coated cables. Got a donated bike in the other day and cable had a black Teflon coating that started to break up causing cable to hang-up. We replace with a standard DER cable and new housing.....all works great now. For your case I would cut some sections of liner or use the sleeve that is inside a v-brake noodle if you are concerned about wear of the plastic guide

https://www.ebay.com/itm/22483045736...96603743da84dc

Airfehr

The teflon coating I have seen covers the entire cable and is thin enough to see the cable strands through it. Brake noodle sleeve is a good idea. I was looking at jagwire slick tube but I think its too wide for the guide slots. Brake noodle is a little thinner.

Airfehr

Did the cable swap today. They are long housing end cap nipples. So a skinny cable liners I was able to reuse. Cheers