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  1. #1
    Senior Member
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    I know I'm not THAT strong... right?

    So,

    I got a new steelie a while back (Jamis Aurora) and it's coming up on time to adjust my derailers etc (which is a little intimidating, as I've only done it with downtube friction shifters before, and this is a STI brifter system) but with them just a hair out of alignment, I noticed on downstrokes I hear a grinding, and looking down, it appears that the chain is rubbing the front derailer when I do....

    Am I flexing the frame to cause this?

    I'm a rather weak commuter (< 15 miles roundtrip a day) and this isn't a 15 lb light is more important than anything flexy flier, although it IS a price-point bike)

    Or is it something else?

    Thanks.

    -- James
    It is easy to win an argument, but the greater reward is to win an ally.

  2. #2
    Member Mr Pantani's Avatar
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    It happens.
    Bianchi EV3 - Campagnolo

  3. #3
    Your mom
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    I don't think it's frame flex. More probable is an out-of-round chainring (most are, by the way) and/or a misadjusted FD. You're not in a bad combo when this happens, are you (small/small, big/big). Cross chaining is a no-no.

  4. #4
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    Quote Originally Posted by tellyho View Post
    I don't think it's frame flex. More probable is an out-of-round chainring (most are, by the way) and/or a misadjusted FD. You're not in a bad combo when this happens, are you (small/small, big/big). Cross chaining is a no-no.
    Big (front) small (back) and generally closer to mashing than spinning when it happens.

    -- James
    It is easy to win an argument, but the greater reward is to win an ally.

  5. #5
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    You may be flexing the chainring/crank while mashing in the big front/small back combo. On my old friction shifter steely I have to nudge the front D when the back D travels to an opposite side. I bet there is an appriciable angle on the chain in the big front/small back combo.



    There's a fine line between laziness and efficiency

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