I have put up to 84 inch racks.  4 bikes hang on the higher one (road bikes) while the lower one has bike tires, extension cords, etc.  Some suggestions: as noted, it would be great if the cover could be fixed so it doesn't slide, vertical ski rack mount would be great, and smaller lengths (36") for limited spaces.  I never bothered buying the hardware and used some 12 X 2 wood screws.