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I know dérailleur adjustments are frustrating, but this is the 4th day i'm working on this... i stop working just before the rage kicks in and leave everything to continue another day :)

The problem is: on the lowest (smallest) gear on front, the guide(?) gear from the dérailleur will grind on half the low (larger) gears on back. on the middle front gear (have 3) only the lowest (larger) gear on back grinds.

This is what I have: Shimano RD-MT60, Deore http://velobase.com/ViewComponent.aspx?ID=3f73f16c-1a7e-46c5-ab73-f21755e71b08&Enum=108

That is not my picture, but the distance from the guide gear to the lowest rear gear is almost the same. it makes a wicked noise on pedaling.

The steps I did last, was to start all over again.

  1. moved index to highest (small) gear. i.e. less pull on cable.
  2. removed cable from derailleur.
  3. left P-screw half inserted.
  4. loosened H-screw (bottom) until it stopped moving outward.
  5. screwed in H-screw until it aligned with highest (small) cog.
  6. pulled the derailleur arm with one hand down and into the wheel
  7. adjusted the L-screw (top) until arm stopped moving to the wheel
  8. screwed in L-screw until arm was aligned with Lowest (big) cog.
  9. let go of arm
  10. adjust cable fine tune to be almost fully inserted in thread
  11. secured cable on derailleur with almost no pull.
  12. pulled cable to remove slack.
  13. re-tightened cable again with almost no pull.
  14. tested index shifting with front on middle gear.
  15. adjusted fine cable pull screw for tight second and penultimate gear shifts.
  16. noticed grind on lowest gear (large).
  17. screwed in P-screw. nothing changed. rage.
  18. tried with front derraileur on highest (small) gear. grinding now on half the low gears on back. more rage.

What am i doing wrong here? What else can control the proximity of the guide pulley/gear and the low gears other than the P-screw?

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Are you sure you have the right derailer and lever set for your rear cluster? –  Daniel R Hicks Jan 29 at 1:47
    
(Ignoring the highest and lowest cogs, does one click of the lever move the derailer exactly one cog?) –  Daniel R Hicks Jan 29 at 1:49
    
1  
That screw has essentially nothing to do with making the derailer center over the cogs -- it's purely to adjust tension in the chain, and, to a degree, adjust how far the jockey wheel stands away from the cog. –  Daniel R Hicks Jan 29 at 2:54
4  
You could always take it to your LBS, hand the guy 10 bucks or whatever and let him set it up for you. –  Batman Jan 29 at 2:56

1 Answer 1

If the derailleur is old, the internal spring which is meant to swing the derailleur out away from the cassette might be worn to the point that it is no longer able to keep the derailleur far enough out. You might be able to replace the b limit screw with a longer screw in order to make it work.

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1  
very good point! I did not check the spring strenght when i renewd the derailleur. I am using it as is and set it up so that it only grinds in the very lowest combinations (which i rarely use for my comute).. but as soon as i have to open it up again for lube/mud removal, i will surelly check it up and update here if that was the case. –  gcb Apr 20 at 21:46

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