What is tongue weight?

Tongue weight (TW) is the static downward force that a loaded trailer's coupler presses onto the hitch ball at the back of the tow vehicle. Picture standing on the trailer's coupler with the trailer hitched — the weight you'd feel pushing down is the tongue weight. It's one of the single most important towing measurements, because it determines whether the trailer tracks straight or starts to sway.

For a conventional bumper-pull trailer, tongue weight should be about10–15% of the trailer's total loaded weight. On aboat trailer the figure is lower (5–7% of the whole loaded rig), and on a gooseneck or fifth-wheel it's much higher — 15–25% of the trailer weight, carried on the kingpin rather than a ball.

Why tongue weight matters

Tongue weight sets where the trailer's center of gravity sits relative to its axle. Get it right and the trailer follows obediently. Get it wrong in either direction and towing becomes dangerous:

• Too little tongue weight lets the trailer's weight sit too far back, turning it into a pendulum that can sway and fishtail at speed.
• Too much tongue weight sags the tow vehicle's rear, overloads its rear axle, and lifts weight off the front wheels — reducing steering and braking.

See tongue weight percentage for the numbers by trailer type, and what happens at each extreme.

Tongue weight vs. pin weight

The idea is the same for goosenecks and fifth-wheels, but the load is carried in the truck bed over (or just ahead of) the rear axle instead of on a ball behind the bumper. There it's calledpin weight or kingpin weight, and it runs a higher percentage of trailer weight — which is why it eats so much into a truck's payload.

Find your number

Use the tongue weight calculator to get your recommended range, thenmeasure the real value once the trailer is loaded the way you'll tow it.