Alex Moll wrote:
> I now see that I have the earlier generation
> Jubilee - my return spring is completely different from yours. Thought
> I'd heard or read that the later generation springs were "stronger" -
> but it just looks like a much better design.
>
> Here's a few pics:
> http://www.flickr.com/
Yeah I went and looked at some Jubilees and found one with the earlier spring like yours, never noticed that difference before (or forgot if I did...)
The old style spring is made from a thinner wire, and that should make it a weaker spring, all else equal. Unfortunately you can't just replace it with the new style spring even if you had one -- the derailleur is different where the spring hooks in at both ends. You _can_ still increase the spring force applied by the existing spring though, by bending it. That doesn't increase the spring constant, but you are increasing the preload. You unhook the lower end as I mentioned before, then bend it upward. Unhooking the lower end is not as easy as on the newer spring design, but it's still pretty easy -- you just have to take the cable anchor bolt out first, then pry the spring bottom end off its perch with a small screwdriver or some such.
Be sure to check the pivots for excess friction while you have the spring off. Bending the spring for higher force is a poor substitute for getting the pivots to move freely.
Also I neglected to mention another source of problems shifting back to the smaller cogs -- have you eliminated cable friction as a/the culprit? Say, by disconnecting the cable completely? (Not a fix of course, just a diagnostic test)
Mark Bulgier
Seattle, WA USA