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Derailleur lost tension

Scotty-GeeScotty-Gee Posts: 156
edited May 2017 in Workshop
It would appear my rear derailleur has lost it's tension in the small ring, see photos.

IMG_3364.jpg
IMG_3365.jpg


I believe this could be a B Spring issue, gunked up or lost tension?

Any ideas? Chain is the correct length, no issues in the big ring etc.

Posts

  • keezxkeezx Posts: 1,316
    1-Take the chain off and figure out what spring/pivot is the problem.
    2-Make a plan of approach.

    BTW, it looks like it's the top pivot....
  • Scotty-GeeScotty-Gee Posts: 156
    It appears to be the upper pivot spring not pushing the derailleur into a horizontal enough position when in small gears. Almost like it needs more B screw but there isn't enough there to give.
  • keezxkeezx Posts: 1,316
    Well , it seems that you'll have to take apart the upper pivot to see what's wrong...
    Most likely the spring is forced out of his hole on one side, happens relatively often with rear deralleurs...
  • Scotty-GeeScotty-Gee Posts: 156
    Been there. Done that.

    Taken apart, cleaned, rebuilt. No change.
  • Looks to me like similar symptoms to a sticky jockey wheel cage pivot spring.
    Don't know if that's still a possible issue with Di2 derailleurs though.
    Does the jockey wheel cage pivot freely and spring back when moved? If not you'll probably find all the grease in there has gone and been replaced by gunk, like mine was. Easy enough job, as long as you wind the spring the correct way when you're putting it back together.
  • Scotty-GeeScotty-Gee Posts: 156
    I don't believe there are springs in the Di2 Derailleurs, rather these are replaced by servo motors?

    Hopefully it is just gunked up.
  • keezxkeezx Posts: 1,316
    No way...
    The top and cage pivots have springs for certain....you"ll have to check them both.
  • looks like the pivot just above the jockey wheels has seized up. Spray lots of wd40 into it and gradually work it loose. i think it happens quite often if ridden in wet or wintery roads.
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