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  1. #1
    mtbr member
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    Q Factor XTR 2x10, 3x10 and XT 3x10

    My new frame requires Q factor of at least 165mm.

    I am particularly interested in the 2x10 but was reading that the Q factor was 3mm less on each side. But am not sure what it was in the beginning.

    Anyone know the Q factors for the 2011 series?

    Thanks!

  2. #2
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    I couldn't track down these figures either. What I was able to find is that the Q factor of the "race" is 3mm less then the "trail". Just like what you said, except the Q factor of the 2X10 trail (38/26) is wider then the 2X10 "race". Not sure that this helps you, but figured I would throw it out there.
    CyclingCentralVa.org

  3. #3
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    What frame do you have?
    Q factor is the measurement to the outside of the crankarm.....and crank arm thickness varies from one model to another.

  4. #4
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    You might also need to be flexible with your choice of ring sizes as some chain stays do not play well with some of the smaller size chain rings.

  5. #5
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    shimano has a gauging tool that goes into your bottom bracket to see if the narrow Q-factor cranks will fit your bike.. its an inexpensive cardboard tool shaped like the cranks... call them, they will probably send you one at no charge.

  6. #6
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    I just ordered a Titus X Carbon 2010. The frame has not arrived yet so in no hurry to buy the components. Want to make it right.

  7. #7
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    Why would q-factor be relevant as far as frame is concerned? Wouldn't bottom brake width be the only crucial measure?

  8. #8
    Old school BMXer
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    Nope...crank arm to chainstay clearance can be very tight on some frames. So tight that some narrow Q cranks can not be used on some frames.
    May the air be filled with tires!

  9. #9
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    Ok, I see. But then I should be concerned with inner distance between crank arms, rather than outer--i.e. Q-factor. Am I right?

    I mean, crank arms can have different thickness, hence different Q-factor, although their inner distance is the same.

  10. #10
    > /dev/null 2&>1
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    Technically speaking yes the q factor is a measure of the distance between the outside of the cranks, but, smaller q factor must also mean smaller inner width . . . you can't achieve smaller q by just shaving off the outer edge of the cranks, the crank arm is carefully designed for the maximum stiffness with minimal material, it needs to be a certain thickness, therefore narrowing the inner width to achieve it.
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