How To Identify BB Shell Failure: Aluminium Threaded Bottom Bracket

[@julesselmes]

A very thorough explanation. Thank you.

[@carbonbikerepair1]

Glad it was helpful!

[@LanceMcGrew]

Do you see this as a design flaw? Seems notorious on older Trek carbon frames. Trek does not want to honor their lifetime warranty on this issue.

[@carbonbikerepair1]

I think lifetime warranty is optimistic if you think it will last. Until the bb is tested properly will you only know. Trek is certainly not alone in its obligations to the customer. I would say they are, by comparison, rather good. Take note brands!