Originally Posted by
chaadster
Failed lines of reasoning aside, I had my bike with the soft, “hand adjustable” derailleur hanger on the stand today to do a little tubeless maintenance since I haven’t ridden it in over a year. After adding some sealant, I took it on the road for a quick spin, only to find the derailleur out of alignment! I could easily see by the cage/cassette alignment what needed done, so I reached down, and with just my hand, pulled the derailleur until things lined up. Voila! Problem solved…again.
of course, it got me thinking about this thread, so I put it back up on the stand to have a closer-than-ever look, and this is what I saw. Obviously the hanger is just soft aluminum, but I wonder if that tiny gap between the CF frame and the notch in the hanger allows the movement to happen so easily, and were the fit snug, that it might resist moving better? In any case, were the hanger stronger, it’d resist bending better.
This is not the problem with the OP's hanger, but it is certainly a source of the issue in many soft hangers.
An easy way to address it is to clean one of the parts and grease the other, then apply some epoxy between them. The epoxy will stick to the clean part but not to the greased side so you can disassemble them again. Such a process is used to "bed" target rifle barrels to their stocks.