You see them more and more on a lot of custom bikes. Perimeter rotors look extremely cool and present 3 main advantages. 1- Showing the full design of your expensive wheels by eleminating the clutter of a traditional rotor/brake setup. 2- An evident powerful braking due to the diameter of your rotor matching the size of your wheels. 3- Better heat dissipation. Cook Customs from Milwaukee Wisconsin offers perimeter rotor kits to install yourself or you can send your dubs and they will do the job for you. Contact Dave Cook on my behalf and check also their very interesting inverted hand levers. Cook Custom Components.