XX Crankset BB30 vs. BB30 I-A, What's The Diff?- Mtbr.com
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  1. #1
    YB1
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    XX Crankset BB30 vs. BB30 I-A, What's The Diff?

    What is the difference between the plain old BB30 and the BB30 I-A versions of the XX Crankset? I ask because I ordered a BB30 crank from my lbs and after having it in a box for awhile I realized when I went to install it that the I-A version that I actually got probably won't work on my '09 Scalpel. One has the spindle attached on the drive side, one on the non-drive side. I don't see how you can use a spacer on the drive side with the I-A version, it's not designed for that whereas the BB30 version with spindle attached to drive side has a flange for a spacer built in.
    Emory Kalahari Kruiser

  2. #2
    The SRAM guy
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    Where do you see a I-A designator?
    An XX BB30 crank will work on your Scalpel. All XX BB30 spindle cranks have the spindle attached to the non-drive side.
    http://www.sram.com/_media/pdf/sram/...cal-Manual.pdf

    You can find the technical manual at the above location, also, there should be a printed installation manual in the box that the cranks came in. Have you reviewed that?
    Chris Hilton

  3. #3
    YB1
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    All my info is coming from the printed SRAM tech doc that came with the XX cranks. In

    http://www.sram.com/_media/techdocs/...0Cranksets.pdf

    there are graphic depictions of five variants of the Truvativ XX crank set: Pressfit 30 I-A, Pressfit GXP, BB30 I-A, GXP, and BB30.

    The big XX tech manual you attached doesn't go into the same level of detail.

    I also found this doc. http://www.sram.com/_media/techdocs/...0Cranksets.pdf It shows the "Mtb" versions. The box the crank came in says "10A FC XX Q156 BB30 2.2 175 2842" I had asked the lbs to order the 156Q verision because I had read here that it would work on the '09 Scalpel 68mm shell.
    Last edited by YB1; 03-13-2011 at 08:08 AM.
    Emory Kalahari Kruiser

  4. #4
    YB1
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    I'm not 100% sure which document of the two the crank came with, road or Mtb. Anyway I'm going to try and install what I got before I assume it won't work. I think it may just be getting the right drive side spacer set on it.
    Emory Kalahari Kruiser

  5. #5
    YB1
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    So it worked! What through me is the 2.5mm spacer set that came with the crank. It just didn't look like there was a surface on the inside of the driveside crankarm for this to load properly against.

    Anyway for whoever wants to keep there old Scalpel chugging along the 156Q XX BB30 fits perfect like has been reported on this site before. Now I have a sweet, rocksolid 2X9 gripshift setup on my bike. I'll add a photo here later.
    Emory Kalahari Kruiser

  6. #6
    The SRAM guy
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    YB,
    The I-A designation is for BB30 cranks that have the "Integrated Adjuster", which the XX crank should have. It's the dial on the non drive arm. Use that to adjust your bearing preload after tightening the arm. Tighten the crank all the way with the adjuster backed off, and then adjust the bearing. Make sure you tighten the little screw on the adaptor to hold the adjustment.

    Make sure you use a 10 speed chain on those rings, or you are going to have a very expensive repair bill one day! a 10 speed chain will work on your 9 speed cassette, it will take a little tweaking on the front D.
    Chris Hilton

  7. #7
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    Since your talking about BB's, can someone tell me the advantage of a press-fit cup style over a threaded? I'm curious.

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