I am installing a 9150 rear derr and I have the option of using a direct mount hanger rather than using the B Link supplied with the RD on a standard hanger.

The RD binds a bit on the DM hanger and doesn't pivot as easily as it does when on the stock B link mounting. Is this free movement necessary or is this more to allow the RD to be pulled back out of the way to facilitate wheel removal? Does the RD body move back and forth such that it needs to pivot forward and rearward on the B Link or DM hanger? I am thinking that it shouldn't but would love some confirmation one way or the other.

I am working with one of these Paragon hangers B4135: 1-1/2" Round and Low Mount Dropouts, Shimano DM Road, 1 mm Hub