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RD will not gut far enough to align w/ small cog

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RD will not gut far enough to align w/ small cog

Old 05-07-20, 06:21 PM
  #1  
hobkirk
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RD will not gut far enough to align w/ small cog

MY APOLOGIES! I expected this was going to be fairly simple - "Oh, you forgot to do XYZ..." - Now that I read your replies, I wish I had done more before I posted.
  • I will dig deeper tomorrow: removing the RD, measuring the alignment angles of the rear cassette relative to the chain rings, vertically and horizontally, use string to test overall alignment, check the alignment of L & R chain-stays to each other.
=====================
The original post is below
=====================
  • The RD is a Shimano Deore XT M772 with long cage.
    • This is a NTB 9 speed RD, but the throw = 10-speed Shimano road system.
    • I've replacing an earlier version, the M771, and I've used that for over 5 years.
  • The Ultegra shifters have not changed (except for a new cable).
  • NO FD for now! But I do 96% of my riding on the middle chain ring so it's no big deal, and it removes one variable from the mix.
  • The alignment of the frame, hanger, crank, etc. all seem perfect from any angle. The only things I've charged are the cable, the RD, and the chain.
I hope the picture is sufficient to explain better. I rotated the image 1 to correct the vertical alignment.



Last edited by hobkirk; 05-07-20 at 09:41 PM. Reason: Apology
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Old 05-07-20, 06:30 PM
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Is this a frame you cold set and you need to align the derailleur hanger after?
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Old 05-07-20, 06:34 PM
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Two things, smallest cog is the high gear, so you adjust the H screw. Also, the cable may be stopping it and you will have to loosen the cable at the derailleur and allow for more. And, make sure you re-adjust the L screw so the derailleur doesn't go into the wheel.

John
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Old 05-07-20, 06:35 PM
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Originally Posted by danmyersmn View Post
Is this a frame you cold set and you need to align the derailleur hanger after?
I don't know what cold set means - the hanger is solidly mounted, aligns perfectly as far as I can tell...
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Old 05-07-20, 06:43 PM
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Does the derailleur go far enough with the shift wire removed and the "H" (not "L") screw backed out?
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Old 05-07-20, 06:56 PM
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To start loosen the cable clamp on the derailleur and if it shifts to the small thentthen cable was to tight.
if not adjust the limit screws. It's easy just watch how it moves as you turn the bolt.
A bit of trial and error will have it working.
But be very carefully you don't adjust it the wrong way so the derailleur can shift into the spokes. Double check when you are finished.
I usually shift it in to the low gear and then snug the limit screw up. And I also push on the derailleur hard to make sure it can't
Remember if it can shift into the spokes it eventually will and be a disaster so take your time.
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Old 05-07-20, 07:45 PM
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Originally Posted by hobkirk View Post
I don't know what cold set means - the hanger is solidly mounted, aligns perfectly as far as I can tell...
Aligned perfectly by eye for 8 speed and up is just "not good enough" in the real world. You really should get the hanger aligned.
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Old 05-07-20, 08:05 PM
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Originally Posted by dedhed View Post
Aligned perfectly by eye for 8 speed and up is just "not good enough" in the real world. You really should get the hanger aligned.
Does that need to done by a "big time" LBS?
Can I do it myself using precise straight edges, etc.?
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Old 05-07-20, 08:06 PM
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Originally Posted by dsbrantjr View Post
Does the derailleur go far enough with the shift wire removed and the "H" (not "L") screw backed out?
Interesting Q - I will check it tomorrow...
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Old 05-07-20, 08:12 PM
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Old 05-08-20, 06:49 AM
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Originally Posted by hobkirk View Post
Does that need to done by a "big time" LBS?
Can I do it myself using precise straight edges, etc.?
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