Bike Forums - View Single Post - Brand new eTap group; *one* cog doesn't shift
Old 03-06-18, 09:57 AM
  #7  
TimothyH
- Soli Deo Gloria -
 
Join Date: Aug 2015
Location: Northwest Georgia
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Bikes: 2018 Rodriguez Custom Fixed Gear, 2017 Niner RLT 9 RDO, 2015 Bianchi Pista, 2002 Fuji Robaix

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Always do the easy and cheap thing first.

Check bolts and fasteners including derailleur hanger to frame, derailleur to hanger and bolts on the derailleur itself holding the cage and pulleys together.

Check for play in the freewheel bearing. I had a bad freewheel bearing and it caused all kinds of missed shifts, skipping and hesitation. It takes a few minutes to check for side to side play.

Is the chain directional? Is it installed in the correct direction? Is it the correct chain? Try a new chain?

Is everything clean and lubed correctly? Battery fresh? Reboot the derailleur by removing the battery? Factory reset? I know little about E-Tap.

Getting to more time consuming diagnosis - Can you isolate the problem? Does the derailleur shift when it has no chain attached? Does it shift when the derailleur is completely disconnected from the bike? Does it only happen when the chain is connected? Does it happen in the stand with light hand power applied to the pedals or only when riding and full leg power is applied to the pedals? This might be one of the first things to try especially if the chain has a quick link and can be easily removed - take the chain off and see if the derailleur moves to the problem sprocket or not. If not then it is a problem with the derailleur and if so then it it may be a problem with either the drive train or the derailleur.




Originally Posted by Marcus_Ti View Post
Check documentation before doing this.

IIRC Di2 documentation strongly advises against ever manually moving a Di2 derailleur's parallelogram.
Agree. Don't force the derailleur to move.
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