Difference between bb30 x1 cranks and gxp x1 cranks

Discussion in 'Parts 'n Stuff' started by the drizzle, Apr 12, 2017.

  1. the drizzle

    the drizzle Likes Dirt

    My mate just got some new x1 cranks to fit on his sb6c

    He bent the others so needed to replace them.

    Grabbed some gxp from velo gear and the spindle is 145mm whereas the x1 cranks he pulled off the spindle is 110mm.

    Just wondering if anyone knows if the bb30 cranks will have a shorter spindle?

    What is the difference between the two other than being designed around different bottom brackets?

    I'm a shimano man and want to help him out but have nfi about sram stuff.

    Cheers
     
  2. The Duckmeister

    The Duckmeister Eats Squid

    BB30 uses a shorter, fatter spindle and narrower BB shell in the frame. There are adaptors to enable fitting a GXP crank to a BB30 frame, but it is not possible to go the other way.
     
  3. JTmofo

    JTmofo XC Enthusiast

    There are 2 types of sram bb30 spindles, wide and narrow.
    I can't remember off the top of my head what the dimensions are, but there are definitely 2 different widths.
    145mm sound like fat bike cranks..... where 110mm sound closer to the mark. Sb6 is pf42 bb shell.

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  4. JTmofo

    JTmofo XC Enthusiast

    Here's a photo of the bb30 spindles[​IMG]
     
  5. Zaf

    Zaf Likes Bikes and Dirt

    I've got this covered thanks to my Stumpy teaching me, the hard way, about BB30/PF30.
    Essentially BB30 is narrower spacing across both the Shell and spindle width, but uses much larger diameter bearings to make up the stiffness. The cranks usually cinch down using wave washers or some such mechanism to remove any lateral play, and these make up the difference in shell and spindle width.

    The easiest thing for him to do at this point, if he owns the GXP crank already, is to get a Praxis Kit or a wheels manufacturing external BB that essentially thread into each other inside the BB30 shell, and space the bearings outboard in the same width as a 73mm BSA would. It also solves most, if not all, of the issues with BB30 creaking.

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    Last edited: Apr 12, 2017
  6. JTmofo

    JTmofo XC Enthusiast

    Sb6 bb is not bb30 compatible. Its press fit 68/73mm, or pf41/bb92.
    Old mate has got the wrong gxp crank, I'd suggest it's a fat bike gxp crank.
    A bb30 crank will not fit.... no matter what adaptor he tries to buy.
    His options are
    1. Send them back and get a 68/73 GXP crank.
    2. Buy a different crank and bb to suit (anything except bb30)

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  7. The Duckmeister

    The Duckmeister Eats Squid

    Make your mind up. It's one of 68mm or 73mm BSA threaded, or 89.5x41 or 92x41 or 92x42mm threadless press-fit, aka BB92.
     
  8. the drizzle

    the drizzle Likes Dirt

    ah sweet, thanks gents

    i thought maybe the spindle was longer as gxp has an external shell whereas bb30 was internal but sounds like it isn't even bb30. 2015 sb6c stock build. He said the width of the axle on his gxp cranks was perfect just the spindle was waaaay to long.

    does sound like he may have got fat bike cranks
     
  9. The Duckmeister

    The Duckmeister Eats Squid

    Seems like it. The assembled width of an external cup threaded or BB92 press-fit GXP-type BB is 96mm. Then allow around 15-20mm extra spindle for the left crank to fit on, a standard GXP should have a spindle around 120mm, give or take a couple.
     
  10. Zaf

    Zaf Likes Bikes and Dirt

    Just Praxxis Kit it and use the GXP crank.

    [video=youtube_share;TB-PovRMeco]https://youtu.be/TB-PovRMeco?t=78[/video]

    Edit: ignore me!! It's a PF92 system, I'm getting it mixed up with the SB5C which runs the PF30. Praxis won't work here.
     
    Last edited: Apr 12, 2017
  11. the drizzle

    the drizzle Likes Dirt

    the box literally has no sticker or information on it, is there a way to tell from the serial number, similar to with the pike to assertain which cranks he was given?
     
  12. The Duckmeister

    The Duckmeister Eats Squid

    ^^ All fine & dandy, except we've established it's not a BB/PF30 frame...
     
  13. Zaf

    Zaf Likes Bikes and Dirt

    Haha yeah, I'm replying and then seeing all the other replies when the page refreshes. :D
    I editted my last comment to reflect that it's best to ignore me and that I was getting confused because the SB5C runs a PF30, and the SB6C runs a PF92. So yeah, NO Praxxis, just a good old PF92 GXP BB, plug and play.
     
  14. JTmofo

    JTmofo XC Enthusiast

    It's a BB92 standard as you well know.
    My point being.... a BB30 crank will not work regardless.

    Being the fountain of patronising knowledge, maybe you could tell OP what cranks his mate actually bought?

    That would actually help.... without being a tool.
     
  15. the drizzle

    the drizzle Likes Dirt

    He bought x1 1000 gxp cranks from velo gear. The spindle fits, just too long. Pretty much 99% sure they just gave him the x1 1000 gxp fat bike cranks which they also sell. He just wants to get it sorted before easter as we are heading up to bright / falls for some shuttles. Thanks for all of your input guys, much appreciated


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  16. Boom King

    Boom King Wheel size expert

    Take it outside gents....

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  17. bear the bear

    bear the bear Likes Dirt

    yeah...nah handbags at five paces ;)
     
  18. The Duckmeister

    The Duckmeister Eats Squid

    What then was the point of saying it could be 68/73mm PF, which is BB/PF30?
     
  19. Zaf

    Zaf Likes Bikes and Dirt

    You could see what he meant. BB30 and PF30 may have a 68/73mm shell width depending on their Road/Mountain application, but JTmofo said it's "68mm/73mm or PF41/92". You could clearly see he was talking about the GXP/24mm style BB that simply has the width of the BSA cups built into the frame and the bearings pressed into that width. If you're going to deliberately misinterpret the comment for the sake of playing semantics, you're a villian and a scoundrel, and should return my top hat at once!
     
  20. JTmofo

    JTmofo XC Enthusiast

    Meh... it's the finer details that don't really count.

    Bb30 won't work...that was my point. I don't like arguing pointless debates so I'll admit I was incorrect in my previous post.

    Off you go now and be happy you were right....

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