SRAM X9 rear derailleur lost all tension

shoulder_of_orion

Hey,

I was cycling up a steep trail yesterday and I suddenly lost all chain tension. First I thought the chain had come off, then I thought the gear cable had snapped, before realising I had a pretty serious derailleur problem. The derailleur still shifts (just about) and I was able to limp home at a snails pace.

The derailleur does not spring back to position, I am assuming that the spring has somehow come out of position. Some basic googling tells me this is/was a common problem with SRAM derailleurs. One person (on another forum) advised that you could get the tension back by removing the wheel and chain and then rotating the derailleur anti-clockwise one rotation on the rear dropout. Keen not to damage anything else though (e.g. thread the dropout?).

Can this be (easily) fixed or am I in the market for a new derailleur?

http://imgur.com/a/h2CDC

I am relatively new back to MTB having had years as a roadie. I have all the tools for Shimano road bikes and am relatively competent and would prefer to fix it if possible but prepared to simply buy a new derailleur if necessary.

I bought this hardly used Whyte 905 secondhand a few months ago so warranty etc is not an option, but the bike itself although 3-4 years old has less than 500 miles on it.

Thanks in advance...

JGTR

Make sure it isn't locked in the open position, SRAM X9 can be opened out and locked into position by pressing the black button in the derailleur body to allow easy removal of the wheel . Usually auto resets by just opening the derailleur again. By opening I mean move the lower jockey wheel forward so it extends fully.

shoulder_of_orion

I have tried pressing the black button but it has no effect at all. The button will not depress at all and seems to be stuck. When I move the lower jockey wheel forward and back the whole derailleur just rotates. When I push it back, the chain tightens to a normal tension, but it will simply drop back to a more forward position (as per the photo in link above).

cooldad

Sure it hasn't just unscrewed, if the whole mech is moving?

shoulder_of_orion

Got this sorted. For sake of completeness I thought I'd post the solution.

Thanks to JGTR for getting me to really focus on the locking mechanism. The whole derailleur was basically jammed in an open position. This led me to this thread: http://singletrackworld.com/forum/topic ... in-tension

The solution posted by otsdr fixed it for me.