Originally Posted by phughes

That is not a rim brake, and it actually was made for a very good reason. With the rotor mounted on the rim, Erik was able to make a very lightweight wheel, since the "spokes" did not have to carry the load of braking. The majority of force went directly to the rim/tires, not the spokes. The lowered the unsprung weight, and lowered the gyroscopic action that works against turning inputs, making the bike much more "flickable."