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  1. #1
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    XX1 BB30 Crank in 68mm BSA Bottom Bracket

    I'm running XX1 BB30 crank in my old-school steel frame.

    XX1 BB30 Crank in 68mm BSA Bottom Bracket-photo-2.jpg

    The XX1 BB30 crank's axle measures ~89mm without the bearing preloader. 68mm BB faced at local shop, measures at 68.3mm.

    I bought external BB30 BSA threaded bottom bracket bearing cups from Enduro. Each bearing cup measures ~10mm, so with BB and cups, total came to ~88mm. I installed the NDS arm minus the preload adjuster. Sure enough, the crank interface barely clears the bearing cup. I installed the DS without any spacers and torqued it to spec. Chainline measures at 49mm per SRAM. The crank spins freely without any drag or play. I've been running this setup without any issues.

  2. #2
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    Hi Ibis,

    I was wondering if I could manage the same feat with 73mm BSA. Could you please tell me whether you had a shorter or longer spindle version of the crank and what is the thickness of the preload adjuster itself ?

    Appreciated

  3. #3
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    Quote Originally Posted by JohnnyNT View Post
    Hi Ibis,

    I was wondering if I could manage the same feat with 73mm BSA. Could you please tell me whether you had a shorter or longer spindle version of the crank and what is the thickness of the preload adjuster itself ?

    Appreciated
    I'm running the short spindle version. The short spindle BB30 XX1 crank is 95mm long and a long spindle is 101.5mm. The length include the splined interface, which is ~6mm, so the measurement you need to work with is 101.5 - 6 = 95.5. I don't know what the preloader thickness is, but it's fairly thick. The spacer for standard BB30 install is 9mm for short spindle and 15mm for long, but for BSA install, you don't need the spacer. The spacer goes on the DS for chainline. I didn't use it and the chainline came in right at 49mm.

    XX1 BB30 Crank in 68mm BSA Bottom Bracket-bb301.jpg

    The long spindle should be enough for 73mm BSA, minus the spacer and preloader. The BSA outboard BB bearing shells are 10mm each, so the spindle length to work with is 93mm : 73+10+10 = 93.

    I bought the BB30 wave washers to take up the slack and provide bearing preload since I removed the preloader all together. I didn't have to use the washers in my setup. After applying specified torque to the crank, there was no play and crank spun freely.

    With 95.5 and 93 numbers that I came up with above, you may need at least one washer. Since "73" BSA measure can be off, you may need some flat 30mm washers to take up the slack if BB is less than 73. Make sure you face the bottom bracket first to align the bearings. Facing also takes some material off, so this may change the final BB width. Take a measurement to get the final number. Hope this helps

  4. #4
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    Thank you good sir, that's exactly info I've been looking for. Planning on buying Rotor BSA BB for 30mm spindle and a Chinese Carbon Frame with 73mm BB. Your input confirms that with longer spindle crank it should work together nicely.

    BTW Are you using AB chainring? The spindle picture is from their website
    Last edited by JohnnyNT; 3 Weeks Ago at 04:24 PM.

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