Why tongue weight matters
Tongue weight is the downward force a trailer’s coupler puts on the hitch ball of the tow vehicle. It is one of the most important factors in safe towing. Too little weight on the tongue lets the trailer sway from side to side, which can quickly become uncontrollable at highway speed. Too much overloads the rear axle of the vehicle, lifts the front wheels and reduces steering and braking grip.
Recommended ranges
| Hitch type | Tongue weight |
|---|---|
| Conventional ball hitch (bumper pull) | 10–15% of loaded trailer weight |
| Fifth wheel or gooseneck | 15–25% of loaded trailer weight |
Whatever the percentage, the tongue weight must also stay below the rating of the hitch, the ball mount, the ball and the vehicle, whichever is lowest. The vehicle’s limit is in the owner’s manual, and the hitch’s is on its label.
How the calculator works
- Tongue weight percentage = tongue weight ÷ loaded trailer weight × 100
- Recommended range = trailer weight × 10% to 15%, or 15% to 25% for a fifth wheel
- Margin = hitch rating − tongue weight
Example
A 5,000 lb travel trailer with a measured tongue weight of 550 lb, towed with a hitch rated for 600 lb:
- Tongue weight: 550 ÷ 5,000 = 11%, within the 10–15% range
- Recommended range: 500 to 750 lb, capped at 600 lb by the hitch
- Margin: 50 lb
Measuring tongue weight
- Tongue weight scale: a simple gauge that sits under the coupler.
- CAT scale at a truck stop: weigh the vehicle with and without the trailer attached to find the load transferred.
- Bathroom scale: for light trailers up to about 300 lb, directly; heavier tongues need a lever setup with a beam and blocks.
Measure with the trailer loaded as you will tow it, tanks included, and level.
Adjusting the load
- Too light: move heavy items forward, ahead of the axle.
- Too heavy: move cargo back, or use a weight-distributing hitch to transfer part of the load to the front axle of the vehicle and the trailer axles.
- Keep heavy items low and centered, and secure everything so it cannot shift.
Sway control devices help, but they do not fix a badly balanced load. If a trailer starts to sway, ease off the gas, keep the wheel straight and apply the trailer brakes gently with the manual controller, rather than braking hard with the vehicle.