Delaminating Bottom Bracket

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Delaminating Bottom Bracket
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Posted: Aug 4, 2021 at 17:50 Quote
I have had 3 frames now where the bottom bracket shell has delaminated from the frame. The first indication is a terrible creaking then a popping sound under heavy pedaling. The carbon around the shell has separated, but there was not any impact in the area, anybody else have this issue?

Posted: Aug 22, 2021 at 18:01 Quote
I just posted about a similar creaking under heavy pedaling. I haven't been able to identify any defect around the bottom bracket shell, but I'd love to rule that out. Can you describe what the delaminating shell looks like it and what signs I should be inspecting for? I'm riding a 2021 Rip 9 RDO. Thanks.

Posted: Aug 23, 2021 at 20:19 Quote
If you grab the cranks and apply some vertical or horizontal force to them without pedaling you will visually be able to see the cups moving in the frame, after removing the crank and cups it’s clear that the carbon/aluminum have separated. Link to my photo of it. Still waiting to hear back on a 4th replacement front triangle.

https://m.pinkbike.com/photo/21183316/

Posted: Sep 9, 2021 at 8:04 Quote
Thanks for the photo and explanation, and apologies for not responding sooner.

Here's what I'm looking at on the non-drivetrain side. Not as clean an interface as the drivetrain side, but not sure what tolerances are or should be. You can zoom pretty far in on the pic and see the right side of the bottom bracket shell not making the cleanest interface..but not sure it's an issue.


Posted: Sep 9, 2021 at 9:32 Quote
Yours looks like it’s not the same issue as mine. I have other angles and on both sides the carbon has separated from in-molded alloy insert. Do you run a chain guide/bash guard? I am wondering if that is somehow related to it, if the ISCG tabs are the weak point.

Posted: Sep 9, 2021 at 21:58 Quote
Thanks. I don’t love the look of it, but maybe it’s within the range of normal. I definitely can’t move the insert. I’m not running a chain guide or bash guard.

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