Toyota 2009 Tundra Owner's Manual page 286

2-5. Driving information
2. Fifth wheel Towing
The king pin weight is 15 to 25% of the Gross Trailer weight.
(King pin weight/Gross trailer weight x 100 = 15 to 25%)
CrewMax models: Current fifth wheel trailer designs are not
compatible with short bed.
The gross trailer weight and tongue load can be measured with
platform scales found at a highway weighing station, building
supply company, trucking company, junk yard, etc.
260
Gross trailer weight
Tongue load
Gross trailer weight
King pin weight