Check out this slightly aged Yakima roof rack. It can hold 2 bikes. Included are the 4 control towers, 2 Sprocketrockets (for the bikes) and the 48" crossbars. Everything you need for a permanent installation. Or you could opt to attached the crossbars and Sprocketrockets to your existing roof rack rails. Paid $450 for this system, looking to offload to someone who can use it.