Gear and derailleur cable advice please

[Accy cyclist]

I read last night on a thread(i think it was about Carrera bikes)that you should keep your cables taut when the bike is not in use. The person mentioned the gear shifters on Carreras stating that "as long as you keep the cables taut they should last for years", or something like that.
Is this correct? I've always slackened my cables after a ride, thinking that keeping them taut will strain them and eventually they wont respond to being moved by the shifters. Is it better to rest them or keep them as taut as possible?
Thanks beforehand to all those who reply!

 

[black'n'yellow]

I don't think it really matters. Never seen any real evidence worth considering in favour of either method....

 

[spacecat]

I can't see how keeping them taught would make then last longer. I usually slacken them off on the shifters by changing up/down at the end of a ride. Doing this though perhaps only reduces the need for occasional cable adjustment caused by them stretching.

But that's probably not applicable these days with modern cables

 

[Pauluk]

Sounds totally OTT to me.

 

[Svendo]

Ah I see, you mean 'slacken' by shifing to small/small when not in use. Not slackening via the adjusters and then re-indexing each ride!

FWIW I recall reading, but not where, that cable stretch is actually the cable's twist tightening under tension, and that the forces in the shift system are no where near enough to actually stretch the steel.
In my experience some cables are made so that they're already as tight as they'll get (e.g. shimano teflon coated - expensive) where as others (e.g. Fibrax teflon coated - much cheaper) aren't, so you have the bedding in period of increasing the tension as the shifting gradually changes down less well until the cable is stretched or in fact 'tight'.

 

[subaqua]

Ah I see, you mean 'slacken' by shifing to small/small when not in use. Not slackening via the adjusters and then re-indexing each ride!

FWIW I recall reading, but not where, that cable stretch is actually the cable's twist tightening under tension, and that the forces in the shift system are no where near enough to actually stretch the steel.
In my experience some cables are made so that they're already as tight as they'll get (e.g. shimano teflon coated - expensive) where as others (e.g. Fibrax teflon coated - much cheaper) aren't, so you have the bedding in period of increasing the tension as the shifting gradually changes down less well until the cable is stretched or in fact 'tight'.

tighten the twist on a cable and it will shorten the cable not lengthen it. it may well be the twist undoing that causes the stretch , although steel wire is fairly ductile.

 

[Svendo]

Oh, I see what you mean. I was thinking of something like a 'chinese finger trap' where when it's looser it's wider and shorter, and you can get your fingers out and when it's 'tighter' it's thinner and longer and your fingers are trapped. This is all second hand hearsay so it's someone else's fault if It's wrong .

 

[Blue Hills]

I don't think it makes much difference. I remember looking into this a fair while ago as I wondered the same thing - I live up a dirty great big hill so gears are always right at the bottom when I get home.

 

[actonblue]

Cables are consumables they degrade with use and therefore will impare shifting at some point. To maintain good shifting cables should be changed at regular intervals.