Any idea what is up with this new slightly different UDH hanger from Shimano?
Why the extra “pin”?
Could it be used to align it with the frame?
My feeling is that they simply don’t want to use the UDH standard outright, but want something of their own that is close enough so that frames are compatible with both.
IMHO it is stupid. By all accounts UDH works very well. At least I haven’t hard that an extra alignment pin is necessary.
I suspect the pin is purely to bypass patent law
It seems like it, it is compatible with UDH frames, as seen at the Vuelta on an Alpecin’s Aeroad equipped with DA 9300:
The UDH is designed to rotate forward if the derailleur is jammed hard enough. It looks like Shimano doesn’t want the thing to rotate at all…
OR
If frame companies start accommodating this new hanger with its little hole, then Shimano can introduce their own “full mount” derailleur that utilizes the hole to index the derailleur. I suspect a big hurdle for skirting SRAM patents is how the SRAM derailleur relies on the grippy plate to index the derailleur.