Toyota Tundra Quick Reference Manual page 301

2-5. Driving information
Selecting trailer ball
Use the correct trailer ball for your application.
276
Trailer ball load rating
Matches or exceeds the gross
trailer weight rating of the trailer.
Ball diameter
Matches the size of the trailer
coupler.
stamped with the required trailer
ball size.
Trailer
class
IV
II and III
Shank length
Protrudes beyond the bottom of
the lock washer and nut at least 2
threads.
Shank diameter
Matches the ball mount hole
diameter size.
I n f o r ma t i o n P r o v i d e d b y :
Most couplers
Typical trailer ball
size
2 5/16 in.
2 in.
I 1 7/8 in.
are