Advertise on Bikeforums.net



User Tag List

Results 1 to 9 of 9
  1. #1
    A Little Bent Hammertoe's Avatar
    Join Date
    Mar 2006
    Location
    Struggling up a hillside in Vermont, USA... ..........................................
    Posts
    2,859
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Rear Derailer Pulley Wheel Rumble....

    I am finishing my Scott CR1 build and almost have it dialed in...

    The pulley wheel (lower jockey wheel) rumbles when in the lowest gear (34/29)...

    Any suggestions to fine tune it...

    The rear derailer is a Record long cage...

    Thanks...

  2. #2
    Senior Member
    Join Date
    May 2004
    Location
    Wilmington, DE
    My Bikes
    2003 Specialized Hardrock, 2004 LOOK KG386i, 2005 Iron Horse Warrior Expert, 2009 Pedal Force CX1
    Posts
    8,767
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Adjust the B-screw maybe? With that large of a cog on your cassette, there's a good chance that the jockey wheel is rubbing on it if you left the default B-screw adjustment in place. Chances are, you'll need to screw it all the way in to remove the rubbing. I had to do the same to get a Shimano road derailler to clear a 28 tooth cog.

  3. #3
    Low car diet JiveTurkey's Avatar
    Join Date
    Aug 2007
    Location
    Corvallis, OR, USA
    My Bikes
    2006 Windsor Dover w/105, 2007 GT Avalanche w/XT, 1995 Trek 820 setup for touring, 201? Yeah single-speed folder, 199? Huffy tandem.
    Posts
    2,359
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    2001 and later Campagnolo uses an A-tension screw, which works opposite of the B-tension screw found on Shimano. http://sheldonbrown.com/derailer-adj....html#btension

    I don't know much about Campagnolo drivetrains, but are you sure you're not exceeding the max cog and/or the max capacity (or whatever Campagnolo calls it) by too much? Is the upper pulley bumping into the cog, causing the lower to rattle front-to-back? Adjusting the A/B tension will help but only to so much of an extent if the specs are being exceeded.

  4. #4
    Senior Member BCRider's Avatar
    Join Date
    Mar 2008
    Location
    The 'Wack, BC, Canada
    My Bikes
    Norco (4), Miyata, Canondale, Specialized, K2 Proflex
    Posts
    5,359
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The lower jockey wheel? One of the jockey wheels is fairly well located and the other floats a little. I can't remember at the moment which is the more loose of the two. The other thought is that the bushing or pin is worn out so that it CAN wobble and create a rumbling sound. Even though it is meant to float side to side a little it's not supposed to wiggle in angle more than a few degrees.

    Finally if it's the metal bushing then grease it. I know they say you don't but they can get pretty darn sticky and hold a lot of muck if you don't. The white ceramic bushings I don't grease.
    Model airplanes are cool too!.....

  5. #5
    Low car diet JiveTurkey's Avatar
    Join Date
    Aug 2007
    Location
    Corvallis, OR, USA
    My Bikes
    2006 Windsor Dover w/105, 2007 GT Avalanche w/XT, 1995 Trek 820 setup for touring, 201? Yeah single-speed folder, 199? Huffy tandem.
    Posts
    2,359
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    The upper pulley floats to line up better with the cogs.

  6. #6
    A Little Bent Hammertoe's Avatar
    Join Date
    Mar 2006
    Location
    Struggling up a hillside in Vermont, USA... ..........................................
    Posts
    2,859
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Gotta love BF...

    Even with all the characters in the other forums, I can always count on Mechanics...


    Although not solved, playing with the "A-screw" and the limit stop, it is better...



    It looks like the chain and lower pulley do not line up...

    As the chain comes onto the pulley the chain is just slightly to far to the outside (or pulley to close to the wheel) so is 'jumps' every few links causing the rumble...

  7. #7
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    24,782
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Hammertoe View Post
    Gotta love BF...

    It looks like the chain and lower pulley do not line up...

    As the chain comes onto the pulley the chain is just slightly to far to the outside (or pulley to close to the wheel) so is 'jumps' every few links causing the rumble...
    Check your derailleur hanger alignment. If the hanger is bent a bit to the inside it could cause the mis-alignment you are seeing.

    Also, it's possible the derailleur cage itself is bent.

  8. #8
    dbg
    dbg is offline
    Si Senior dbg's Avatar
    Join Date
    Nov 2004
    Location
    Naperville, Illinois
    My Bikes
    2004 Trek 5900 Superlight, 2001 Lemond BA, Dozen other muts
    Posts
    2,253
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by HillRider View Post
    Check your derailleur hanger alignment. If the hanger is bent a bit to the inside it could cause the mis-alignment you are seeing.

    Also, it's possible the derailleur cage itself is bent.
    +1
    I have one of those derailer hanger alignment bars but don't use it much. I think you can eyeball it pretty well.
    David Green, Naperville, IL USA (Trek 5900 Superlight), (Lemond BA), (Peugeot UO8 (SS)), (Dozen other muts)

    "The older I get, the better I used to be" --Lee Trevino
    "I told my psychiatrist that everyone hates me. He said I was being ridiculous; everyone hasn't met me yet" --Rodney Dangerfeld

  9. #9
    Senior Member BCRider's Avatar
    Join Date
    Mar 2008
    Location
    The 'Wack, BC, Canada
    My Bikes
    Norco (4), Miyata, Canondale, Specialized, K2 Proflex
    Posts
    5,359
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Once past the first pulley the chain should be routed by the cage. I'm betting the cage itself or the pulley bolts are tweaked. Unless the hanger is WAY off and the chain line is pulling the chain off the pulley.
    Model airplanes are cool too!.....

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •