sproket wobble

Discussion in 'Motorized Bicycle General Discussion' started by macattie88, Jan 15, 2010.

  1. macattie88

    macattie88 New Member

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    i installed my rear sproket tonight and im trying to eliminate all wobble but cant seem too....how much can you acutually get out and what can i expect as far as movement from side to side?im sitting behind the wheel and spinning it to see how much it wobbles.
     
  2. 2door

    2door Moderator
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    Seek perfection... Any wobble is not good and the worse it wobbles the more trouble it will cause you. I don't go as far as using a dial indicator but if I can discern ANY wobble I keep working until I can't. The sprocket should spin as true and wiggle free as you can get it. Lateral wobble could be the result of a warped sprocket, not unusual, and you might need to resort to a hammer and a block of wood to get it flat. Verticle movement, or non-concentricity is caused by the sprocket not being exactly centered on the rear hub. I have never encountered this but some folks have found sprockets with the center hole drilled off center which obviously could cause real headaches trying to get it to run true. Keep working. It takes a lot of patients to get that sprocket to run perfectly true but you'll be rewarded with a smoother running chain/bike if you get it right. Start by snugging all nine bolts then in a star pattern, alternating from side to side, tighten them and keep testing by spinning the wheel. When all bolts are good and snug spin the wheel and mark the wobble with a felt tip pen. Tighten or loosen the bolts as required to get the sprocket to run true. If it appears that it is warped, remove it and lay on a flat surface such as sheet of glass and check it for flatness. If its warped, get the warp out by using a soft head hammer, a block of wood or a large Crescent wrench to bend it flat. Hope this gets you in the ball park. Let us know how you make out.
    Tom
     
    #2 2door, Jan 15, 2010
    Last edited: Jan 15, 2010
  3. Cannonfish

    Cannonfish New Member

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    You should be able to get that sucker pretty much dead on, with no wobble. I played with my sprocket mounting for what seemed like forever in order to get it lined up right, and it eventually paid off - I had no detectable wobble whatsoever.

    If you can notice that wobble at slow revolution-speed, then it will be quite pronounced when your bike gets up to speed.

    So keep messing with the sprocket mounting until you're convinced that the wobble is gone (assuming that your rear wheel is actually in true, and your sprocket is a good one). If you're still not happy with it after that, check out Manic Mechanic's link on the left-hand side of your screen - he makes a "sprocket adapter" that will entirely eliminate your wobble (I believe there's also another guy on this forum making them now too).
     
  4. Cannonfish

    Cannonfish New Member

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    Oops, 2-door already said all this, I just type too slow :)
     
  5. Cabinfever1977

    Cabinfever1977 New Member

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    When you tighten the bolts on the sprocket you have to tighten the bolts in a crisscross patern(like lugnuts on a car),which is tighten a bolt(but not all the way yet) then tighten a bolt across from that one,then go to a oposite side of the sprocket and do the samething,keep doing that all around the sprocket,keep checking for wobble while youre doing that,then if its good go all around and finish tightening all the bolts in a crisscross patern.
     
  6. 2door

    2door Moderator
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  7. Spunout

    Spunout MB Builder Extraordinaire

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    ah...heres a potential issue:
    is your sprocket dished, with narrow teeth? if so, then the wobble something you can correct.
    IF NOT...then you have a stamped sprocket, flat on both sides? wide teeth?

    those stamped-out ones are CRAP. imagine holding a frisbee with both hands, then twist each hand in opposite directions. WARP!
    ive taken every single stamped one and lain it on a flat surface. every single one has been warped. no matter how perfect you try to get them, it will never be right.
    does this sound familiar?.....chain binds up and gets tight on half the wheel turn, and jumps off on the other turn?
    two options:
    1. grind the sides of the teeth down. alot.
    2. get a dished sprocket.
    good luck. i know its frustrating.
     

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