Spend the money - buy a Thule Sportsworks Rack (see thuleracks.com) - a hitchmounted rack. Holds up to 4 bicycles very securely. Tucks away up against the vehicle when not in use. Very easy to use you won't have to climb "Mt. Everest" to get to the bikes. Plus trust me on this, roof racks on such a large vehicle will eventually lead to smashing hte bikes into a parking garage, it will happen!