Should we be lubricating cables which already have a plastic liner in the outer?

[Cyclopathic]

I don't put extra lubrication on my new cables because they are already have a plastic liner which seems to make the cable flow very well. My concern id that a lubricant may well start to erode the plastic liner and cause it to get jammed up over time and also that a lubricant may just attract dirt which will stay in the cable and again clog things up.
How do you approach this and what are your conclusions?

 

[mickle]

Shimano provide grease in their new cables whilst most cycle mechanics use a couple of drops of chain lube or a squirt of gt85. If you're using stainless cables its not do important but cheapo cables will eventually corrode without some form of water repellent lube down the cable.

 

[Cyclopathic]

Shimano provide grease in their new cables whilst most cycle mechanics use a couple of drops of chain lube or a squirt of gt85. If you're using stainless cables its not do important but cheapo cables will eventually corrode without some form of water repellent lube down the cable.

As I understand it GT85 and similar evaporate to leave a coating. Do you think it would be best to treat the cable and let the excess evaporate rather than putting it into the cable where it may create an attraction for bits of grit.
I have thought that ordinary cables should have some protection but have opted for what I thought might be the less problematic. Based on what you say I may revise my technique and at least let a coating form on them before installation.

 

[e-rider]

spray a bit of GT85 down the outer cable (i.e inside the outer), and apply a good coating of grease to the inner wire - this will make the cables work perfectly for a few years!

if shimano grease their cables like they grease their hub bearings they wont last longer than 5 minutes.

 

[snailracer]

In my experience, the inner cable often rusts, which roughens and swells, scuffing the plastic sleeve resulting in "sticking" cables. The best way to avoid this is to specify stainless steel inner cables. Occasionally, due to water ingress, the steel outer cables rust, which swell and squeeze the inner cable, again resulting in excess friction, but apart from mounting the cable so it doesn't rub and scuff the plastic outer sleeve, there is not much you can do about that as you cannot lube the outer wires and they tend not to be stainless steel.

Silicone lubes (e.g. service spray, car wax, dielectric grease) are more tenaciously water-repellent than oil or grease, and also repel dirt. However, there is a small theoretical chance that any lube (oil or silicone based) will react with the plastic sleeve, although I have never personally come across a confirmed case of that. Lighter lubes will, in theory, be more reactive than more viscous greases, however they don't hang around as long, so their overall tendency to react with the plastic sleeve is hard to assess.

 

[tyred]

I put a little oil on a rag and run the inner cable through it to leave a film of oil.

Something I picked up from my dad years ago, no idea if it offers any real benefit but doesn't seem to do any harm either.