Any bicycle mechanics here?

[natto fire]

Hey, I believe the rear derailleur on my bike is causing some bad drive line noise. The chain is rubbing against the cage holding the tensioner sprocket and not meshing great to the sprocket itself. Also if you are on the biggest sprocket and backpedal, the derailleur shifts automatically to the smallest sprocket.

I have not checked the cables, not sure how much tension they have.

Bike is an '06 Ellsworth Epihany, SRAM X0 components.

 

[996GT2]

Is the derailleur bent/damaged?

If not, check the cable tension and make sure the H/L limiters are properly set.

 

[wetomb]

http://www.sheldonbrown.com/derailer-adjustment.html

 

[Sid59]

Also might wanna read or post on http://www.bikeforums.net - tons of helpful people and a dedicated section for mechanic help.

 

[Zap]

jonnyGURU used to work as a bike mechanic, many years (decades?) ago.

 

[Sulaco]

Did someone call for a....BICYCLE REPAIRMAN?!?

http://www.youtube.com/watch?v=U01xasUtlvw&feature=related

 

[Don Vito Corleone]

It's very likely the case that the cable tension is just too low. There is a barrel adjuster on the shifter (and usually one on the derailleur as well) to adjust tension. Turn it counter-clockwise to increase tension until your shifting is back in order. This an adjustment that will take just a few seconds.

 

[natto fire]

Thanks for all the replies so far. I forgot to mention that the actual shifting is still pretty smooth, and the rubbing noise is louder on bigger cogs/higher load. The bike does have a separate derailleur hanger which might be bent.

I went through that sheldonbrown website but can't find the symptom I have having be described. I am pretty sure it is not the H/L adjustment because it goes through all the gears and doesn't try to throw the chain.

I'll do adjust the tension and report back.