Originally Posted by
Wilfred Laurier
You seem to be missing the point of replaceable derailleur hangers - they are supposed to be the weak link in the chain so they fail before anything else does in the case of an impact. If an OEM one was readily available, sure, but if not, there should be no hesitation to go to an aftermarket hanger, especially if your other option is to use a 'repaired' hanger, like the one that caused the problem that resulted in this thread.
The point is that it is supposed to be the "weak link".
And, as you suggest, it should fail before taking out the whole rear end of the bike (although that leaves the derailleur hanging loose).
If you were to replace say a carbon fiber hanger with a machined aluminum hanger, it could have very different properties than the OEM hanger.
I'm surprised that even the aluminum OEM hangers aren't designed with fracture lines.
A lack of long-term OEM supply chains for parts designed to fail is a problem.