I figured that I’d have a little fun with this since I, once again, worked out this system.
I call it StepDown. It allows a frambuilder to design a rear dropout that is a little more compact than the existing IS would allow. Since most bikes and especially hardtails don’t need to ever run a large 203mm rear rotor, we can use a more efficient design.
Current revised information from my 2018 disc brake study:
Below is older (first gen) information: