Chain tensioner question

Discussion in 'Motorized Bicycle General Discussion' started by cottonball, Mar 8, 2009.

  1. cottonball

    cottonball New Member

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    Would it be ok to put the tensioner above the chain pulling down? Reason I'm asking is I was riding my bike and the chain pulled the tensioner down into the spokes and warped my back wheel. So I was hoping to prevent this in future by having the tensioner above the chain instead. Please let me know your thoughts and what not. Thanks for your time.
     
  2. Creative Engineering

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    By putting the tensioner on the top; the tensioner will be subjected to the power of the engine...it will fail quickly!!!

    More than likely the chain tensioner was pulled into the spokes because the rear sprocket is not concentric to the wheel. When the sprocket is out of concentric with the wheel the chain will tighten and slacken as the wheel turns. When riding, the constant change in chain tension is hard on the idler.

    Check your sprocket, and get it as concentric to the wheel as you can. Remount the tensioner, and have a helper hold in the clutch lever while you spin the rear tire by hand. Check to see if the chain has a constant tension.

    DO NOT adjust the tensioner so that there is zero slack in the chain. With the tensioner adjusted correctly you should be able to move the top side of the chain, in the middle, about 1/2"

    Jim
     
  3. cottonball

    cottonball New Member

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    Thanks for the info. I didn't explain myself properly at first. I want the tensioner still mounting on the bottom, but the pully will be ontop of the chain pulling it towards the ground instead of up to the air.

    Would it still be subject to the power of the engine?

    Also the sprocket was concentric with the wheel. Guess I'll see how tomorrow goes after I get a new rim.
     
  4. Dave31

    Dave31 Moderator
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  5. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    You can mount it the way you've described with no ill effects. The chain may still cause it to go sideways if it's not tight enough though.
     
  6. danajohnhill

    danajohnhill New Member

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    I'm pretty new to motorized bikes, so take this for whatever it's worth. I had the same issue. My tensioner moved, my chain went into the spokes and my wheel went way out of true. I asked around here and got conflicting opinions about going without a tensioner. I decided to take a chance, and, so far so good. I had to take a couple links out of the chain, of course, but the fit and feel is great now. If the chain stretches a little I can just pull the wheel back a little bit.
     
  7. cottonball

    cottonball New Member

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    Thanks for the info. I replace my rear wheel this morning, mounted it back on the bike and put the tensioner pulling the chain down. Anyway I took it for a 20 mile ride and everything went flawless. I hope it keeps up because it is a BLAST to ride. Yes it is my first but not my last bike. I plan on building another but a 2 stroke instead of a 4.
     

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