I mounted mine by screwing some longer bolts in to the standard mount holes along with some large flange washers. Then I wrapped some 8mm accessory climbing rope with a loop on each end around each "post" I had created, and wrapped it ~5 times around a passenger grab-bar, hooked the end loop back to the start loop, and there it hangs. Bonus: when moving, you just rotate it up and hook another small rope to it and it's totally out of the way, and just "wiggles a little" while driving