FCS Surfboard D Ring Soft Rack (more info in the description)

Common complaint and personal observation with using these type of surfboard soft racks, is that no matter how tight you pull the straps below, the boards are not stable at highway speeds.
Somewhat by accident I realized that when the cushion pads are rotated 1-2 times, you effectively tighten and shorten the straps. With this move, my 9’ or 10’ longboard sit happily at highway speeds. They will also sit quietly on your roof while you drive without a board, alleviating
the flapping if you don’t take them off.
Disclaimer: Doing so may cause premature failure of the webbing so keep an eye on potential damage where the turns/rotation on the webbing occurs. Typical 1” tubular nylon webbing has a breaking load of 4000lbs. Also, keep and eye on the door weather stripping where the webbing passes over into the vehicle. Leaving straps on for extended period of time may damage/pinch the seals. Best of luck.