hey guys i just got a thule roof rack for my toyota corolla and i was wondering how fast i can go with surfboards on it? i mean a surfboard is a fairly big area and looks like an airplane wing kind of. is there a certain speed where the pressure becomes to much and it will just rip the rack off the car, or the board snaps in half? im just wondering how fast yall go normally and if i should stay under 70 or something like that on the interstate?

thanks
AJ