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This is an interesting example of things I see from time to time.
A broken CF frame [this one a Moto Immortal].
Can you guess what caused this? What can you tell from the pictures?

I am putting no spin on this; just an open question as to most likely cause in your opinion.

Of course, I know some posters are pro-BD, others are anti-BD, and others are indifferent. That is not the Spirit of the question; and this question could be about any brand, model, etc.; as you probably know.

I know many posters here have seen a lot and studied all things cycling; so I am truly interested in educated guesses based on these photos.





 

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Had that exact same thing happen to a Time bike I had shipped. I recovered my cost through shipping insurance. Thank goodness for insurance. I believe my mistake was shipping the bike with the back wheel off the frame.
 

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Is that grass stuck in there?

If this happened while riding then it either hit something softer than metal or the derailleur hangar broke for some reason. I have been riding along next to somebody who's derailleur suddenly snapped off for no apparent reason, which then caused the chain to become wedged between the cassette and frame and locking up the rear wheel. Frame and tire were both toast. It would be useful to see the derailleur up close to see where it is damaged other than the cage being ripped apart.

If this happened while not being ridden, then something put some force on the derailleur without taking out the wheel.
 

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I'm wondering is how did the rear derailleur cable get stuck in the chain in one of the photos; was this breakage caused by the derailleur cable getting stuck on the chain then it ripped the dropout off as he was pedaling? I know it sounds silly, but the OP said it was odd!
 

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MarshallH1987 said:
Is that grass stuck in there?

If this happened while riding then it either hit something softer than metal or the derailleur hangar broke for some reason. I have been riding along next to somebody who's derailleur suddenly snapped off for no apparent reason, which then caused the chain to become wedged between the cassette and frame and locking up the rear wheel. Frame and tire were both toast. It would be useful to see the derailleur up close to see where it is damaged other than the cage being ripped apart.

If this happened while not being ridden, then something put some force on the derailleur without taking out the wheel.
derailleur hangers don't break 'for no apparent reason' ...there is always a reason when something breaks. always.
as for the photos...i'm gonna guess that somewhere along the line this bike fell over onto the derailleur or was shoved in the back of a car or something fell against it, and the hanger was bent. rider then rode, shifted into the largest (probably) cog, derailleur went into the spokes, and this is how it ended up. there is a mark on the inside of the drive side seat stay that looks like it might be impact from the derailleur coming around while caught in the spokes.
as long as it happened while riding, that's my guess. it's pretty hard to break a hanger while the bike is stationary(in the 'inward' direction), as it's tough to push the derailleur in far enough.
 
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