Ford 2008 F-250 Owner's Manual page 213

Payload – is the combined weight of cargo and passengers that the
vehicle is carrying. The maximum payload for your vehicle can be found
on the Tire Label (vehicles exported outside the U.S. and Canada may
not have a Tire Label) on the B-Pillar or the edge of the driver's door.
Look for "THE COMBINED WEIGHT OF OCCUPANTS AND
CARGO SHOULD NEVER EXCEED XXX kg OR XXX lb." for
maximum payload. The payload listed on the Tire Label is the maximum
payload for the vehicle as built by the assembly plant. If any aftermarket
or authorized dealer installed equipment has been installed on the
vehicle, the weight of the equipment must be subtracted from the
payload listed on the Tire Label in order to determine the new payload.
The appropriate loading capacity of your vehicle can be limited
either by volume capacity (how much space is available) or by
payload capacity (how much weight the vehicle should carry). Once
you have reached the maximum payload of your vehicle, do not add
more cargo, even if there is space available. Overloading or improperly
loading your vehicle can contribute to loss of vehicle control and
vehicle rollover.
2008 F-250/350/450/550 (f23)
Owners Guide (post-2002-fmt)
USA (fus)
Tires, Wheels and Loading
213