I carry 10 25 litre barrels on the back of my pick up every day plus 2 backpacks and a trolley and stacks of other bits and pieces that us wc,s use every day without any problems, if i break hard they arent going anywhere, at the end of the day a car is a car and its purpose is to carry people ! not barrels of water, and work equipment , you need the correct tool to do the correct job, and a car isnt it.