I've spent hours with my bike on the stand. On the stand: it performs great. When I ride, I can cause the rear gears to shift just by changing how hard I pedal (the harder i pedal, the higher up on the cassette the chain will jump. If i let up, the chain will drop into a harder gear)

I've replaced almost everything: Cables/Housing Cassette and Chain, even the rear deraillure hanger and deraillure.

Any ideas would be helpful.

  • See bicycles.stackexchange.com/questions/7420/… while pedaling standing up bike crank gives in as if shifting what is causing? – user5369 Oct 8 '13 at 9:59
  • @Gary.Ray I agree it is a duplicate, but while those questions have answers, none have been accepted, and none are definitive, IMHO. This would have to be one of the most common cycling mechanical issues, so it be good to have a really solid (possibly community generated) answer. – andy256 Oct 9 '13 at 0:59
  • The top answer has more than double the votes, is clear and concise. The reason it hasn't been accepted is that the original author abandoned it and hasn't been back on the site in over a year. – Gary.Ray Oct 9 '13 at 21:18
  • @Gary.Ray Yes the top answer does have more than double the votes. It is clear and concise. But it doesn't answer the OP's question about rear derailleurs. The question referenced by Look Alterno is certainly relevant also, and has good relevant answers. Again, none have been accepted. Is there a way we can create a community answer? I would be happy to contribute! – andy256 Oct 10 '13 at 2:19
  • I'll agree that this question is a duplicate, although I think my problem was different than his. Discovered my frame is failing near the bottom bracket :/ Should I delete this question? – mrsoltys Oct 10 '13 at 2:20