Rear derailleur adjustment

Discussion in 'Cycling Equipment' started by DrunkenBiker, Jun 3, 2007.

  1. DrunkenBiker

    DrunkenBiker New Member

    Joined:
    Jun 3, 2007
    Messages:
    72
    Likes Received:
    0
    Hola,

    Cannondale M400. Shimano LX rear derailleur.

    I can adjust the derailleur so that it shifts fast and smooth for all cogs except for the top *or* bottom cog. On both of those, it goes to the cog but hesitates for several pedal revolutions before shifting off it. Meaning I can only really use 7 of the 8 cogs on the hub at any given time depending on my adjustment.(yes I've heard that all gears shouldn't be used due to chain angle. I don't when riding. I just want it setup correctly)

    I can't finesse it to have it shift correctly for all cogs.

    Just learning how to maintain my bike. I hope I explained this right

    Thanks for any ideas.

    John
     
    Tags:


  2. gclark8

    gclark8 New Member

    Joined:
    Apr 13, 2004
    Messages:
    3,522
    Likes Received:
    3
    The Low Limit screw will effect shifting into the largest cog. Strike a balance between what you have now and overshifting. :D
     
  3. DrunkenBiker

    DrunkenBiker New Member

    Joined:
    Jun 3, 2007
    Messages:
    72
    Likes Received:
    0
    Thanks for the reply.

    I think I explained it wrong tho. :D

    I can adjust the low/high limit screws so it goes into top and bottom cog perfectly......shifts *in* to those gears fine.

    But I can only adjust it so it shifts *out* of one of them right(top or bottom).

    I can't get it to shift out of both top and bottom cogs with same settings. It hesitates up to 5-6 pedal revs for one of them.

    And 10 bucks says I explained it wrong again. lol

    John
     
  4. 1id10t

    1id10t New Member

    Joined:
    Apr 11, 2005
    Messages:
    343
    Likes Received:
    0
    If you've set the limit screws correctly you might want to try the cable tension adjuster barrel on the rear of the derailleur. This is the part into which the cable housing/cable is inserted. Maybe there's too much/little tension in the cable. Support the bike so the rear wheel is off the ground, turn the cranks and simultaneously turn the adjuster. Do this only in quarter turn increments. Hopefully this might yield some results.
     
  5. mcrowe

    mcrowe New Member

    Joined:
    May 10, 2007
    Messages:
    6
    Likes Received:
    0
    I have problems with my Shimano rear derailleur. First, I can't shift to the smallest cog. Second, the gear shifter show tjat the the chain is on cog number 7 but it is actually on cog number 6.

    Does anyone know what's wrong? Please help.

    Thanks
     
  6. 1id10t

    1id10t New Member

    Joined:
    Apr 11, 2005
    Messages:
    343
    Likes Received:
    0
    Here's a link to the Park Tools how-to on derailleur adjustment.

    http://www.parktool.com/repair/readhowto.asp?id=64

    Try this first. After that I would then be looking at the cable tension (see my previous post).
     
  7. p38lightning

    p38lightning New Member

    Joined:
    Apr 19, 2004
    Messages:
    418
    Likes Received:
    3
  8. mcrowe

    mcrowe New Member

    Joined:
    May 10, 2007
    Messages:
    6
    Likes Received:
    0
    Thanks for reply. The website has quite good information of bike maintenance.

    I have tried the basic derailleur adjustment. Perhaps I should try to look at the cable tension.

     
  9. JungleBiker

    JungleBiker New Member

    Joined:
    May 17, 2004
    Messages:
    119
    Likes Received:
    0
    It could be your derailleur hanger is not straight so that no matter how much you tweak the screws and cables it will never be working perfectly. There is a special tool which a good bike shop should have that is used to check and adjust the alignment of the hanger.
     
  10. effectivepull

    effectivepull New Member

    Joined:
    Dec 30, 2005
    Messages:
    12
    Likes Received:
    0
    i have another rear derailleur issue. i run the sram rival group.

    i can get the gears to shift smoothly on the bike stand using the barrel adjuster.

    BUT, if the chain is on the smallest cog in the back and the big chain ring and i apply additional torque on the crank (or actually riding the bike), the chain jumps. it doesn't move up to the next cog or embed itself against the frame, it just kind of jumps (i can't see it, but can feel and hear it) and settles back in but does the same thing again if apply torque again.

    it's driving me nuts!

    can anyone help?
     
  11. alienator

    alienator Well-Known Member

    Joined:
    Jun 10, 2004
    Messages:
    12,596
    Likes Received:
    160
    You need to twiddle with the limit screw.
     
  12. kdelong

    kdelong Well-Known Member

    Joined:
    Dec 14, 2006
    Messages:
    3,477
    Likes Received:
    74
    Are ya sure this is a limit screw problem? Sounds more like worn cogs, chain, or chainring would be the culprit here. Check your chain. If it is within specs, then you may have to replace your cassette and/or large chainring. Now you're probably gonna tell me that the bike is only 2 months old. :confused: If that's the case, twiddle with the limit screw.:rolleyes:
     
  13. effectivepull

    effectivepull New Member

    Joined:
    Dec 30, 2005
    Messages:
    12
    Likes Received:
    0
    thanks! i just got back from borders and look up the symptom in one of the bike mechanic books - it said the likely cause is a screwed up chain, or bent cog. i don't think either is the case since the bike and components are new (07 Cervelo Soloist) with less than 40 miles on it, no crashes.

    i'll give the limiter a go and see what happens.
     
Loading...
Loading...