Trailer loading and balancing for safe towing
https://wiki-coast.win/index.php/Trailer_loading_and_balancing_for_safe_towing
Loading a trailer is about balancing the weight so your tow vehicle stays stable on the road. You want about 10–15% of the trailer’s weight on the hitch, never more than the tongue weight limit. Heavy items go over the axle, midway. Loose loads shift and cause sway, so strap everything down tight. A balanced rig tracks straight, brakes predictably, and keeps the tailgate from wagging the dog. Take an extra few minutes to test your setup before hitting the highway.