My roof rack uses the metal ribs below the rubber rain gutter (pull the gutter up and look). It looks wimpy, but it's NOT. When I made my roof rack, I was maybe 1/8" off, I tried hitting it with a 12 lb sledge to bend the roof "tab" over - it would NOT budge. I'm confident the weight limitation won't be what the rack can hold, but what will make my kick too darn top heavy.