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RV glossary · Weights & towing limits

80% rule

Also called: 80 percent rule

A common rule of thumb: keep a trailer’s loaded weight (or GVWR) at or below 80% of your vehicle’s tow rating. It leaves a margin for wind, hills, heat and rating optimism. It’s a guideline, not a legal limit.

The 80% rule is popular because tow ratings are measured under ideal conditions, and real towing adds headwinds, grades, high temperatures and imperfect weight balance. Staying under 80% usually means better control, less strain on the engine and transmission, and more stopping margin.

Using the trailer’s GVWR (rather than its dry weight) for the 80% comparison is the conservative approach, because it covers the trailer at its maximum allowed load. The rule doesn’t replace checking payload, GCWR and axle ratings.

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Related terms

Tow rating
The maximum trailer weight a vehicle is rated to pull, as published by its manufacturer. It depends on engine, axle ratio, cab, bed, drivetrain and tow package, so the same model can have very different ratings.
GVWR
The maximum an RV (or a truck) is allowed to weigh when fully loaded, including everything inside it: cargo, water, propane, batteries and, for motorhomes, passengers. It is set by the manufacturer and printed on the weight label.
Payload capacity
How much weight a truck or SUV can carry: its GVWR minus its curb weight. Passengers, cargo, the hitch itself and the trailer’s tongue or pin weight all count against payload.

More weights & towing limits terms

UVW · Dry weight · CCC · OCCC · GCWR · GAWR · GVW · Hitch weight

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