I've had this problem from time to time. The solution seems to have several parts -- but it all comes down to one thing. Everything needs to be clean and smooth so the cables run freely. Remove your shift cables and thoroughly clean and inspect them. If you see any rust or corrosion on them -- particularly in the areas where they run through cable guides or housing -- replace them. They are available in stainless steel with a very smooth finish, and the little bit of extra cost is worthwhile. Next, check any housing you are using and make sure there is no corrosion inside. Most modern housing has a nylon lining inside which should prevent problems -- but older-style housing is often unlined and could get pretty crusty inside. If it's dirty, clean it thoroughly. If it's crusty and rusty, replace it. At the bottom bracket, check your cable guides. Once again -- clean thoroughly. If the cable guides are nylon, then keeping them clean is probably all you'll need to do. If the guides are just channels in the steel, you might find that the cables will wear through the paint and then rust will be the result. Clean off the rust. Touch up the paint. Now - about your idea of using brake cable housing between the guides -- Are you using the whole cable housing? Or just the small diameter nylon liner that is inside the cable housing? Because I've used the nylon lining in my bottom bracket cable guides and I don't think it's a bone-headed idea -- It is only a problem if crud is building up in there and moisture is getting trapped and rusting the cable. Again -- keep it clean. Remember that too much lube can attract dirt and grit which will completely negate the benefit of the lube.
Whenever I've had the autoshifting problem, cleaning the works almost always solves it.
Kyle Brooks Akron, OH
> [Original Message]
> From: Dr. Paul Williams <castell5@sympatico.ca>
> To: <classicrendezvous@bikelist.org>
> Date: 8/4/2007 3:59:02 PM
> Subject: [CR]Autoshifting
>
> 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.