Originally Posted by
HillRider
Well, we have to separate elongation under load (elastic deformation) from a permanent slight elongation when a new cable is first put into service as the strands bed-in against each other and/or settle into the end ferrules. The first type occurs with every shift and is automatically compensated for while the second type occurs initially and is why minor adjustments to the cable "tension" are needed for the first ride or two after a new cable is installed.
There are formulas for both elastic deformation and permanent elongation. But, yes, I'm talking mostly about the second type. Settling into the ferrules is much less of a problem than many people make it out to be. I use metal cable housing ferrules so there is no "settling" in of the cable housing into the ferrule and I seldom see any difference when using new outer cable. But I do see "stretch" of the inner cable due to the bedding of the cable. This is the "stretch" that many people deny exists.
Originally Posted by
HillRider
I try to compensate for the bed-in type of elongation by pulling firmly on the cables before making my initial shifting adjustments. I usually works so only very minor adjustments are needed after the first ride.
I agree that this helps but it doesn't solve the problem entirely. And, again, it's the bedding in that I'm talking about and that many people deny exists.
Originally Posted by
HillRider
BTW, if you do use teflon coated cables, be certain to scrape the coating completely off where the cable clamps to the derailleur. Otherwise the cable WILL slip no matter how much you tighten the clamp bolt.
I've never had a problem with the cable anchoring properly. The teflon coating is very thin and teflon, while slick, is also soft and deforms easily under pressure. I don't use noticeably more pressure on the anchor cable and my Teflon coated cables aren't overly deformed at the pinch bolt over uncoated cables.