I've used Kynar heat shrink tubing on bare cable at points where it may contact the frame or a component. Stuff is tough as nails, clear and shrinks tightly around the cable when heated (you need a heat gun or high wattage hair dryer) so it moves when the cable moves and is fairly unnoticeable. It also helps reduce cable wear.
It's readily available from electronics supply houses online (like Allied <http://www.alliedelec.com/>). It's more expensive than polyolefin, but polyolefin shreds easily. (Also, Kynar has a lower dielectric constant, not that it matters inn this application.) I've not had any problems with cables I've treated this way.
Phil Sieg Knoxville, Tennessee USA
Dr. Paul Williams wrote:
> I am about to put my Raleigh up on the stand tonight to try to solve the
> problem I have been having with autoshifting. The cable guides on my
> frameset run beneath the BB shell and for the longest time I ran the
> cables bare through these. When rebuilding the bike with SR parts a few
> years ago I had the bright (and maybe bone-headed) idea of using some
> left over pieces of brake cable housing between the guides to keep the
> cables clear of crud. I have a feeling now though that this set-up may
> be contributing to the dreadful autoshifting I am experiencing (I have
> read Sheldon's piece on this and have tried to lube the cable - but the
> housing may be full of crap or the cable may be catching somewhere). Any
> ideas from the group?
> An autoshift of two or three gears on a climb is hell with a 52-42 and a
> 12-19 freewheel!!!
> Thanks in advance,
> Paul Williams,
> Ottawa (but on a long weekend break in Kingston) ON, Canada.