21. Hitch must be rigid in all directions at all times. A hitch angle of 0 to 30 degrees maximum is allowed with no leeway. This will be measured from hook point to hitch attachment point on the frame. Draw bar length, measured from center of rear axle to hook point, will be a minimum of 27% of truck wheelbase. Steel hitching device will be no more then 1 1/8 inch thick, no less than 3/4 inch thick. Hitch height is not to exceed 26 inches. It must be visible, clear hook mounted in horizontal alignment. All hitches will have only one adjustable supporting point and it must be located no more than 6 inches from hook point. That supporting point, if mounted to frame, must be vertical if the attachment is from above or below. If attachment is to the rear end, it must be at or below the center point of axle. No part of the draw bar and/or draw bar assembly framework may protrude through the box floor. (2009)
Hope this helps.