The Cosmic and Jet are legal because you cannot remove the fairing. They are integral to the wheel, and because the carbon IS structural to a degree, you can say it contributes to the strength of the wheel, which is how those wheels get around that legality. The only difference between the Cosmic/Jet and other carbon rims with aluminum brake tracks is where the spokes are anchored. With a typical carbon/alu rim, the spoke nipples are seated on the inner circumfrence of the carbon fairing. The Cosmic/Jet anchor in the aluminum rim bed. If properly made, you can have this construction and still have a wheel that is stiffer than a regular aluminum box rim, hence why it is legal.