Direct Mount chainr...
 

Direct Mount chainrings and GXP BB

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I'm putting a new GXP BB on my bike that has a DM chain ring. It looks like the bolts on the chain ring will rub on the ridge of the BB, Is there meant to be a washer or something between them and the BB so it doesn't rub?


 
Posted : 02/12/2023 8:17 pm
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Is it a Nukeproof BB?


 
Posted : 02/12/2023 10:02 pm
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MTB or road?

Pressfit or BSA?

If the former there should be a spacer (and maybe wavey washer) between the chainring and BB.

If the latter - what width BB shell and what spacers are you using between the shell and BB cups. The spindle is effectively held in place by the NDS bearing (clamped on the other side by the other arm) which sets the gap at the other end - if you have the right spacers.

Check the docs for details.


 
Posted : 02/12/2023 10:42 pm
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BSA MTB. SRAM GXP BB. That’s a lot of caps. I’ve got a ring that fits the spindle that’s the same size as the one that goes on the drive side end of the BB but is slightly longer and has a couple of bites out of it. I think it came off the spindle next to the bolts, but it’s the same diameter as the BB washer so doesn’t seem to fit inside it.


 
Posted : 02/12/2023 10:53 pm
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For BSA GXP there should be no spacers on the spindle, just potentially the ones between the BB cups and the frame - one on either side for 68mm shell, none for 73mm shell (see p15/16 in the link above).


 
Posted : 02/12/2023 11:02 pm