Bike Racks Accessories. Green Valley Or Thule Available here. Our range of bike rack accessories allows you to get maximum use out of your bike rack. If you are using a spare-tyre or rear-door carrier, a bike may need a bike-frame adapter for proper mounting to the carrier, and a cable bike lock can prevent theft by locking your bike to the rack. Another safety accessory is a lightboard, which illuminates the rack and any mounted bicycles for motorists traveling behind your car. If you need to transport three bikes instead of two, an adapter is available that expands the capacity of your carrier. Adding bike racks accessories to your existing carrier gives you more versatility and security when transporting bicycles by car.