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Thread: Chain vibration

  1. #1
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    Chain vibration

    well i got my SS setup working properly and had a blast jamming down stairs and hucking over loading ramps without my chain constantly skipping over a mess of cassette cogs

    but sometimes when i'm just cruzing along the chain will start to vibrate up and down... and i can feel it throughout the bike. it does it really often if i spin the cranks by hand (like in the stand)


    i've seen it before but have no idea as to put an end to it

    maybe the chain is too tight? it has about 1/4" - 1/2" of slack... which seems right to me.

  2. #2
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    sounds like your chainline might be off or your chain is too tight.

  3. #3
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    maybe it is the chainline, i just looked at it with a straightedge and it's a tad off. i'll play with it a bit and see what happens

  4. #4
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    You need to center your chainring. Check it for lateral runout while your at it. The chain vibrates because the tension is inconsistent through its travel. Too tight at some spots, too loose at others. Sheldon says:

    Quote Originally Posted by SheldonBrown
    If the chain is too tight, the drive train will bind, perhaps only at one angle of the pedals (chainwheels are not usually perfectly concentric). It should be tight as it can be without binding. If the chain is too loose, it can fall off, usually at the most inconvenient possible time.

    Set the rear axle so that the chain pulls taut at the tightest part of the cranks' rotation. One at a time, loosen up each of the stack bolts, and tighten it back just finger tight. Spin the crank slowly and watch for the chain to get to its tightest point. Strike the taut chain lightly with a convenient tool to make the chain ring move a bit on its spider. Then rotate the crank some more, finding the new tightest spot, and repeat as necessary.

    This takes a little bit of your hands learning how hard to hit the chain, and how loose to set the stack bolts, but it is really quite easy to learn.

    Tighten up the stack bolts a bit and re-check. Tighten the stack bolts in a regular pattern, like the lug nuts on a car wheel. My standard pattern is to start by tightening the bolt opposite the crank, then move clockwise 2 bolts (144 degrees), tighten that one, clockwise 2 more, and so on. Never tighten two neighboring bolts in a row. You may prefer to go counterclockwise, but try to get in the habit of always starting at the same place and always going the same way. This reduces the chances of accidentally missing a bolt.

    Once you have the chainrings centered and secured, adjust the position of the rear axle to make the chain as nearly tight as possible without binding. Notice how freely the drive train turns when the chain is too loose. That is how freely it should turn when you are done, but with as little chain droop as possible.

  5. #5
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    i think that may be the problem cause the tensioner does move up and down slightly as i pedal

    i'll definatly give it a try!

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