Payload = The amount of downward weight your truck is rated for. You will find this number on a yellow sticker in the door jamb, and it will read "CARGO PLUS PASSENGERS MUST NOT EXCEED xxxx"
This would be inclusive of the pin weight or tongue weight of your trailer, the hitch, you, your dogs, your wife, your kids, and is unique to your truck.
When you begin to reach the max payload or exceed the max payload, your truck won't break, however, physics is no longer...