This is one of my favorite pics! We milled the outside flange of the hub so it could be used to drive the rotor hat. We did that for many reasons. I was out one day looking at Sandwich's Ducati and noticed the rotor was completely floating on the hat. The reason you float the rotor on the hat is to prevent the dreaded brake shutter. You see, most rotor hats are sandwiched between the rotor hub and the wheel. So, if there is ANY tolerance (unevenness) on the machining of the wheel (always) or the hub (we try very hard to keep that minimal) then the tolerance will show up as a vibration in the brakes. Over the years, people (customers) have gotten less and less tolerant of the brake vibrating.
By driving the rotor hat on the outside of the hub, we completely decoupled the rotor hat from the hub and wheel. Now the rotor spins freely and is able to move left, right, up and down without vibrating the caliper pistons. This was one of my brighter ideas. At least, I think so. We'll see how it works in real life soon
