Re: chain jumping; quite frustrating, help?

[Qui si parla Campagnolo]

eric-<< and even now, just riding along on the flat
at 15-20 mph without any unusual pressure applied, it will jump. the
especially disconcerting part is all of a sudden, it feels like i just
shifted into neutral of a car, with almost no resistance at all. i just
start spinning like crazy. >><BR><BR>

The chain is dancing or skating on top of the cogs rather than having the chain
engage the cog teeth. I think a rear der problem, with the top pully or the
rear der alignment..Something is not keeping the chain on the cog selected.



Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

[Harris]

eric paul zamora > wrote:

> i have a 1983 bianchi campione d'italia which i upgraded to a regina cx
> 12-21 freewheel around 1984. probably had a regina oro chain at the time.

> a couple of months ago, i brought it out of retirement (i'm 36 and looking
> to lose weight).

> almost immediately, i bought a sachs PC-58 chain. installed it with the same
> length. i was reminded of that little problem when the skipping continued.
> strange thought i. well, maybe it's that particular worn cog. so i bought a
> regina america 6 speed 13-22 freewheel which showed no wear to my eye.
> surely that would solve the problem...

> i installed it this past weekend and it still skips (the new sram chain
> probably had about 200 miles with the old cx freewheel). the problem
> manifests itself by generally jumping to the next smaller cog, but usually
> moves to riding along the top of that next cog first. it's very

The new chain AND Freewheel should have solved the skipping problem
(unless the "new" frewheel is worn).

The auto shifting could be a different problem. Make sure the under BB
cable guides are clean and lubed, and maybe replace the short housing at
the rear der.

If all else fails, treat yourself to a modern derailleur. Since you're
using friction shifting, any modern derailleur will work and will give
much better performance than the 20-year-old Campy.

Art Harris