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  1. #1
    Senior Member JAJ0404's Avatar
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    Feel stupid - chainring Q

    I changed my small chainring, and when I was putting it back together I noticed the small knob on the outside of the large chainring. I had noticed it before, but never paid much attention to it.

    Real question - does this knob need to be lined-up up with anything?

    Curiousity question - what's the purpose of this little knob?
    Quote Originally Posted by big john View Post
    There are no rules, just don't be an idiot.

  2. #2
    Senior Member Homebrew01's Avatar
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    The knob should be next to the crankarm. It prevents the chain from getting jammed between the arm and chainring if you overshift.
    Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike

  3. #3
    Senior Member
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    If it's the one I'm thinking of then the purpose is to keep a dropped chain from getting wedged between the crankarm and the spider. It should be lined up with the crankarm so it fills that gap.

  4. #4
    Gammal cyklist Reynolds's Avatar
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    It goes behind the crankarm. It's there to avoid chain jamming if the chain falls.

  5. #5
    Senior Member JAJ0404's Avatar
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    Thanks guys, of course that's where I had it, and before I tightened everything, I said 'that can't be right' and I moved it from behind the crank. If I could harness all the extra work I've caused myself in my lifetime - - - I could retire.
    Quote Originally Posted by big john View Post
    There are no rules, just don't be an idiot.

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