Tongue weight: the 10–15% that keeps your trailer straight

What tongue weight is

Picture the trailer as a see-saw balanced on its axle. Everything loaded ahead of the axle tips weight onto the coupler at the front — that's tongue weight, and it rides on your hitch ball and, through it, on your truck's rear axle. It isn't a fixed property of the trailer: it changes every time you move cargo, fill a water tank, or strap a generator to the A-frame.

Why the 10–15% rule exists

For a conventional (bumper-pull) trailer, the industry guidance is to keep tongue weight at 10–15% of the loaded trailer weight. Both edges of that band are there for a reason:

• Below ~10% — sway. A tail-heavy trailer is dynamically unstable. At highway speed a gust or a passing semi can start a pendulum oscillation (fishtailing) that gets worse, not better, as it builds. This is one of the most common causes of loss-of-control with travel trailers, and no sway bar fully rescues a badly balanced load.
• Above ~15% — overload. Extra tongue weight piles onto the hitch and the tow vehicle's rear axle, unloads the front (steering) axle, and eats the truck's payload. The trailer tows straight — but the truck is the problem now.

On a 7,000-lb loaded trailer, the band works out to 700–1,050 lb of tongue weight, with about 840 lb as a comfortable middle.

Gooseneck and 5th-wheel trailers are a different geometry: their pin weight sits over or ahead of the rear axle, and the guidance is higher — roughly 15–25% of the loaded trailer. Sway matters less; payload matters even more.

How to measure tongue weight

Always measure with the trailer loaded the way you'll actually tow. Three ways, most to least accurate:

• CAT scale (truck stop). Weigh the hitched rig with the truck's axles and trailer axles on separate pads, then unhitch and weigh the truck alone. The difference in truck weight, hitched vs. unhitched, is your tongue weight. Costs a few dollars and gives you every other number you need — see how to weigh your trailer.
• Dedicated tongue-weight scale. A small scale that sits under the coupler jack. Fast, repeatable, accurate enough for adjusting load between trips.
• Bathroom scale + lever (light trailers only). The classic driveway method: coupler on a beam across a scale and a fulcrum, with the geometry multiplying the reading. Works for small utility trailers; don't put a heavy travel-trailer coupler anywhere near a 300-lb bathroom scale's rating.

How to fix tongue weight that's off

Tongue weight is set by where the load sits, not just how much there is. A common rule of thumb is to keep roughly 60% of cargo weight ahead of the trailer axle. Too light on the tongue? Shift cargo forward. Too heavy? Shift it back — a little at a time, because load position acts like a lever. Watch your tanks too: a water tank ahead of the axle adds tongue weight when full and removes it when empty, so the same trailer can be balanced on the way out and swaying on the way home.

One more thing tongue weight does: it counts against your truck's payload and GVWR like any other cargo. That's the link that makes payload — not the tow rating — the real limit on most half-tons. And if your tongue weight runs over about 500 lb, a weight-distribution hitch is usually the next conversation.

Related: tongue weight calculator · how to weigh your trailer · payload vs towing capacity.