Tongue weight

Tongue weight is the downward force a trailer's coupler applies to the hitch ball, normally 10–15% of the loaded trailer weight for a conventional trailer.

How this site uses it

Too little tongue weight causes trailer sway; too much overloads the rear axle and payload. Manufacturers publish a maximum tongue weight per configuration and the year pages show it next to the trailer rating.

The tongue weight calculator gives the 10–15% target range for a trailer weight and converts a bathroom-scale lever reading to an actual tongue weight.