Slate CM wrote:
All Tundras made starting in 2007 use the J2807 engineering standards for payload and towing.
So those take into account the weight of the w/d hitch at 70#, and 150 for each front passenger. There other parameters including cooling capability on a long grade, launch and acceleration and trailer sway.
The tow ratings include those things but the payload does not. Payload is ALL passengers and cargo (WD hitch is cargo) in the vehicle. The payload sticker should account for the truck as shipped from factory with full fluids (including tank of gas). Any dealer options added after won't be reflected in the payload sticker.
The best way to find out what your truck can carry is to go the scales and weigh it empty with a full tank of gas then subtract that number from your GVWR. That leaves you with now munch weight you can add to the vehicle with people, cargo, tongue weight, etc.