Originally Posted by
trailangel
[SUP]1[/SUP]stretch
verb \ˈstrech\: to make (something) wider or longer by pulling it
: to become longer or wider when pulled
[SUP]1[/SUP]elon·gate
verb \i-ˈlȯŋ-ˌgāt, (ˌ)ē-, ˈē-ˌ\: to make (something) longer or to grow longer
the point is more that the storage of the cable under normal 'rest' tension doesn't cause them to elongate.
the initial stressing of the cables does cause them to elongate (structural stretching), but full elongation is normally achieved in the first few hundred miles. this is because the cables aren't prestretched and is the result of the individual strands bedding into eachother (if you measured, the diameter would be ever so slightly reduced while the length would be increased around 1%)
after that, the cables would undergo elastic stretching when you apply the brakes which is the actual deformation of the individual strands.
bike cables being so small, and the overall load being so low, you're well below the threshold for plastic deformation of the cable, meaning it's still in an elastic state where once the load is removed it'll return to it's previous length
easiest way to confirm: check your brake cable next time you're not applying the brakes. I think you'll find it's not under a lot of tension at all.