The Thule Short Roof Adapter allows you to use the Aero Foot System on cars with short roof-lines. Some vehicles require this adapter to achieve proper bar spread for sports racks. For 2 door vehicles and pickup trucks, it may be necessary to use the Short Roof Adapter to achieve a functional bar spread between the front crossbar and the back crossbar. Each crossbar needs to be mounted in the doors. In a 2-door vehicle, like the Acura RSX for example, there is only approximately 8" - 12" of usable space at the top of the door-frame, which would yield a very narrow crossbar spread. By using the Short Roof Adapter, you can mount a 2nd crossbar up to 30" behind the first crossbar. The system still mounts in 2 spots on the tip of the door-frame, but with magic, extends the 2nd crossbar back further on the roof.
The Thule 477 Short Roof Adapter been discontinued and replaced with a new version, The Thule 487 Traverse