The FatCat 4/6 ski rack has a built-in riser in each rack that is designed to lift up one side of the rack up to allow for more clearance.
You can use the 5/32 hex wrench provided in the hardware to release the riser by following step 10 A - I of the instructions.
Still have questions? You can submit a request to you support team here, or by phone at 888-925-4621 M-F from 7 to 4 PT