I've wondered- is the weight limit a structural (roof damage) issue or some carryover from the roll-over days of yore? I would think that the roof, which can survive a roll-over intact, could support more weight. I would also bet that the average driver adding 300 pounds of gear to the roof would be a recipe for handling mishaps. "I had the refrigerator and water heater strapped to the roof securely. I don't understand why the truck tipped over on the off-ramp."