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  1. #1
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    How do I know my Q factor on my current cranks?

    I am upgrading my cranks to XX1 from XX. I have a 2012 Superfly 100 pro size medium and need to know hat my current Q factor is so I can order the same in this crankset.

    I believe it is the smaller 156 I believe but I am not sure. I have the BB95 internal bearings on the frame.

    Any quick help would be great so I can get these ordered.

  2. #2
    Biking Like Crazy!
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    I believe the Q156 is the more common size used for FS bikes.

    I've had mine for a year now and I remember that being the reason.

    EDIT: just did a quick search here and Q factor has to due with how wide your hips are?
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  3. #3
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    Quote Originally Posted by blcman View Post
    I believe the Q156 is the more common size used for FS bikes.

    I've had mine for a year now and I remember that being the reason.

    EDIT: just did a quick search here and Q factor has to due with how wide your hips are?
    Front what I can tell the current X0 cranksets are a 167.5 Q factor so I believe that the XX would be about the same and i should possibly think about getting that in the XX1 crankset

  4. #4
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    Quote Originally Posted by simpy16 View Post
    Front what I can tell the current X0 cranksets are a 167.5 Q factor so I believe that the XX would be about the same and i should possibly think about getting that in the XX1 crankset
    Okay I looked on SRAMs site and they say the XX crank has a Q factor of 156. So i guess with the XX group they narrowed it a bit.

    I am still really confused but I am back to leaning more towards getting the 156.

  5. #5
    Biking Like Crazy!
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    Quote Originally Posted by simpy16 View Post
    Okay I looked on SRAMs site and they say the XX crank has a Q factor of 156. So i guess with the XX group they narrowed it a bit.

    I am still really confused but I am back to leaning more towards getting the 156.
    Go to the Sram site here on the forums and do a Q factor search like I did and you will find the Q factor
    is more to do with you hip width and comfort. To narrow and it might hit your frame.
    It's confusing tho!
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  6. #6
    Formerly of Kent
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    You could just measure them, you know...

  7. #7
    Rogue Exterminator
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    Quote Originally Posted by Le Duke View Post
    You could just measure them, you know...
    Not real hard to do and you wouldn't have to worry about somebody telling you wrong.

    There is a couple simple was to do this.

    1) Flip the left crank 180 degrees and measure the points.
    2) If you have a dial caliper you can measure from one crank to the seat tube, the other crank to the seat tube, and the width of the seat tube. Add up all the measurements and have your answer.




    Here are the points you are looking for


  8. #8
    AOK
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    XX cranks come in either 166 or 156 Q. On mine the Q factor is printed on the crank arm near the pedal threads.

    Best method is just to measure them.


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  9. #9
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    I am currently riding a GT Peace 9er with Stylo singe speed cranks and I just bought a Stumpjumper carbon 29 Single Speed frame and I have to get new cranks for it. XX1 is my first choice for my new single speed BB30 crankset and I have no idea what Q Factor I need. Is there any way to tell what my Q Factor is without pulling my crank flipping it around and going to my LBS for a spoke ruler?

  10. #10
    transmitter~receiver
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    um... measure?
    Quote Originally Posted by pvd
    Time to stop believing the hype and start doing some science.
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  11. #11
    Always Learning
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    Quote Originally Posted by austinTRON View Post
    I am currently riding a GT Peace 9er with Stylo singe speed cranks and I just bought a Stumpjumper carbon 29 Single Speed frame and I have to get new cranks for it. XX1 is my first choice for my new single speed BB30 crankset and I have no idea what Q Factor I need. Is there any way to tell what my Q Factor is without pulling my crank flipping it around and going to my LBS for a spoke ruler?
    Measure from the outside of the drive side crank arm where the pedal inserts to the other side of the seat tube (line them up first, of course). Now do the same on the other crank arm. Add those two measurements together = A

    Measure the width of the seat tube = B

    Subtract the seat tube from A.

    A - B = Q factor

    Or something like that. I'm a musician, so after I count to 4 or maybe 6 if it's in a slow 6/8 time signature, I'm usually in the dark.

    BB

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