3

I had a mild spill today on my new bike, which put the (Tiagra) derailleur cage a little bit out of line. With some bending and eyeballing, I got the two jockey wheels lined up 'almost' perfectly parallel with the cassette, and shifting is okay.

My problem is, when I shift down to about the 3rd largest gear and larger, the cage 'ticks' when pedaled about 240 degrees (not in the same spot, just after about that much pedalling). I watched the cage and what's happening is, the chain starts to drift to the right (outside) of the lower jockey, and then, for some reason, one end of a link rises up off the jockey, and the cage pulls back a little bit like it's trying to get in position for a shift. It doesn't go far, though, and by the time the bunched link gets off the lower jockey, it loosens up and the tension drops out of the cage, causing it to relax into position again.

None of this happens on smaller gears. What's going on here? Can I fix it without shelling out cash for a whole new derailleur (was basically new)?

Improve this question
2
  • 4
    Unless you're fairly good at bike maintenance, take it to a bike shop. Likely the derailer or hanger is still slightly bent and it needs to be straightened, plus the limits and barrel adjuster may need tweaking. This should be relatively inexpensive. In fact, if you bought the bike through a local shop take it back there -- you're probably due a free adjustment anyway.
    – Daniel R Hicks
    Dec 28, 2013 at 14:19
  • Took it in to the LBS and he carefully bent it till it stopped riding wrong (excepting low-high cross from back to front).
    – bright-star
    Dec 28, 2013 at 23:43

2 Answers 2

Reset to default
1

From what you say the chain tension is now too high.

There should be a screw that adjusts the tension of the tensioning spring. Sorry I can't tell you where it is: none of the images I can find show it. Check out these sources.

Before adjusting anything take note of the position of each screw, then find the one that you think adjusts the tension and turn it one whole turn and test the result. If it messes up something else, it's the wrong screw so turn it back again. If it changes the twitching and clicking it's the right screw, so adjust it until the it's as good as you can get it. Keep track of how many turns you make, in case you need to start again. If that happens try adjusting in smaller steps.

Edit: see also the links in this answer.

Improve this answer
3
  • 1
    It's pretty rare to have a screw for adjusting chain tension. Usually it's fixed, or adjustable only by moving the spring between tangs. And I doubt that chain tension is the problem anyway.
    – Daniel R Hicks
    Dec 28, 2013 at 14:21
  • Seasons Greetings @DanielRHicks. What is your suggestion?
    – andy256
    Dec 28, 2013 at 21:14
  • @DanielRHicks Ah ha. Found your suggestion on the OP :-)
    – andy256
    Dec 28, 2013 at 21:17
1

As Daniel surmised, the issue was alignment of the rear derailleur hanger. Some creative bending by my LBS held me off for a while until I finally brought it too close to the hub on a hill and torqued the whole thing into a twisted mess. Swapping in a new derailleur of the exact same type (and new hanger) cured it completely.

Improve this answer
2
  • You might want to invest in a spoke guard. They are considered vulgar by purists, but they can save your derailer, and can also prevent a bad spill.
    – Daniel R Hicks
    Oct 13, 2014 at 1:25
  • I have the tiny stock one, but it naturally didn't help. I'll keep an eye out for a larger one with more bling.
    – bright-star
    Oct 13, 2014 at 1:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.