Pickup Truck Capacities for Towing RV Trailers

Is the 80% Towing Rule Safe?

As explained in our other articles, such as the Travel Trailer Towing Weight Calculator, the 5th Wheel Towing Weight Calculator, the EZ Towing Weight Calculator,  and the Cargo and Truck Selector Calculator, calculating the actual towing capacity of a vehicle at any time takes some time!

In an effort to avoid this math and issue a general rule of thumb, many people preach the 80% safety margin rule: You should never exceed 80 percent of your tow vehicle’s maximum towing capacity.

For instance, if your vehicle has a maximum towing capacity of 8,800 lbs, as a rule of thumb, you should never exceed 8,800 x 0.80 = 7,040 lbs.

This rule, like most general guidelines, is a useful back-of-the-envelope calculation. It alerts people to the fact that you should rarely, if ever, max out your vehicle’s capacities. However, the results are rarely accurate on an individual basis.

In fact, in many cases, particularly for smaller tow vehicles like crossovers, SUVs and half-ton pickup trucks, applying the 80% rule will often allow you to exceed your capacity! You’ll be overloading your tow vehicle. 

For larger vehicles, such as one-ton trucks, the 80% rule may be too conservative. You won’t get as much cargo carrying capacity out of your RV as you could.

For a truly accurate calculation, use one of the Changing Gears towing weight calculators. 

What Is SAE J2807? 

SAE J2807 is a towing standard developed by the American Society of Automotive Engineers. It contains rules a series of tests for how vehicle manufacturers can specify maximum tow ratings for their vehicles.

The standard was first written in 2008. Over the next 10 years, beginning with Toyota, auto manufacturers began to adopt it, realizing that customers required transparency and reliability.

Today, J2807 has been adopted by every major automotive manufacturer. So you can (usually) trust that manufacturers are issuing maximum towing capacities based on the same standard.

The star of the show standard is the Highway Gradeability test, which takes place on the  11.4-mile-long Davis Dam Grade in Arizona. It’s hot, steep, long, and punishing. The tow vehicle must tow the tested load at a minimum speed of 40 mph with no failures of any type or diagnostic codes. A minimum temperature of 100 degrees Fahrenheit is required at the base of the climb, and the A/C must be running non-stop!

The Davis Dam highway test is designed to stimulate the toughest sustained towing conditions a vehicle might face. However, the test also allows for near minimal tow vehicle weight.

Here’s the equation used by the standard to calculate the Towing Weight Rating (TWR):

TWR = GCWR – TVTW

Subtract the weight of the tow vehicle from the Gross Combined Weight Rating, and you get the maximum towing capacity.

The standard also has provisions and requirements for braking performance, acceleration, handling and sway, reversing, etc.

For a full review of the standard, check out this Motor Trend introductory article.