Our trailers are all car trailers so the movable weight (the car) can be shifted to add or subtract weight from the front axle. A welder friend has a Ford diesel with a large diameter heavy wall pipe that angles back on both ends that is an air tank. Used it numerous times when we had the tractor pull track and a bunch of equipment with tires that always needed a shot of air. I guess that since the truck is a 4wd it also helped plant the front tires.
