Originally Posted by
2left
I'm having a problem that I'd like to diagnose before I bring it into the shop. I don't trust the guys by me and if I can fix it, all the better. Here's the deal:
Bike is shifting to another gear with a big "Chunk" mostly when I stand or put a heavy load. I can't reproduce it on the bike stand. It happens in big and little ring, various cogs in the back, but smallest cog in back in particular. I noticed that when I PULL on the rear derailleur cable, the right shifter clicks into the next gear. This doesn't happen on my other bike, which leads me to believe that it is a problem with the shifter, but I'm not sure. Otherwise, the shifter clicks just fine up and down. I'm guessing this shifter has about 7000 - 10000 miles on it since it was overhauled (I got this bike used, I put around 6000 of those miles on it).
I'm running Campy Record/Ultegra 10sp mix, new(ish) chain (about 150 miles). I just replaced the cables and housings (maybe I did something wrong??). Cassette & wheels arent the issue because I tried two separate wheels w/ two different cassettes and problem persists.
Thanks - I'm trying my best to learn!
Your problem is probably a result of a Campagnolo/Shimano mismatch.
http://www.ctc.org.uk/cyclists-libra...gears/shimergo Assuming you are not using a shiftmate, as the drive train wears the mis-match problems become more evident. In your case the chain has been the verge of shifting (and does so by simply pulling on the rear derailleur cable). you say you have a new chain (150mi); I would venture to guess the ghost shifting started with the chain replacement..either way you might want to look into a shiftmate. Also you may have a small kink in the new housing which can cause this problem.