Bike Friday Mechanical Wisdom Sought
(Posting here before wandering to the Mechanics Section...)
So: my 12-year-old Pocket Rocket is skipping gears, both up and down, and not only under load.
My LBS swapped the (worn) chain, and the 8speed cluster looked worn too -- it was a Shimano HG-70, but (after calling BF to confirm) it started life as a NINE-speed set, which had the largest ring removed so that it would fit into the Sachs 3x7 gear hub. The LBS said that these days those gear sets are usually welded together, so just unscrewing one wasn't an option -- so we switched to a SRAM mtn-bike gearset that could be modified in this way (did I mention that my shifters and derailleur are Campy?).
But: it still skips around! Quite badly and randomly, even on flat roads.
So before I go back to my LBS (who are not, by default, Campagnolo dealers...), I'm pinging the wisdom here, in hopes of enlightenment.
The Ergo levers and derailleur are Campagnolo "Daytona" (now called "Centaur"). Is this likely to be an issue of weakened springs? Can these be swapped out, or am I looking at tracking down a new (old) derailleur? Can a new (new) one be used? Am I right in thinking that this is the old old style Daytona, rather than the new old style Daytona derailleur? This 2000-era bike is right on the "cusp" of a Campy design change...
Thanks for all insights!