I have a roof mounted rack. The factory crossbars are plenty strong. After driving my Griffen into the garage I put my Felt IN the VX now unless I absolutely have to use the roof rack. The rack I use is no longer available and needed slight modding to work with the factory crossbars. "TucsonVX" had custom adapters fabbed to adapt his(I think there are pics in his gallery). Also look through Rickshaws gallery. He has a roof mounted rack on his factory bars also that is done nicely.