Why was the SAE J2807 towing standard created?

Before SAE J2807 was published in 2008, there was no standardized test protocol for tow ratings in North America. Each automaker set internal criteria, leading to deceptive marketing wars where advertised capacities could not be verified or compared fairly across brands.

What is the Davis Dam climb in the SAE J2807 test?

The Davis Dam test takes place on Arizona State Route 68, climbing 3,000 vertical feet over 11.4 continuous miles at 5% to 7% grades in minimum 100-degree Fahrenheit ambient heat with the air conditioning on maximum. The vehicle must maintain at least 40 MPH without boiling coolant or overheating transmission fluid.

Do all automakers selling trucks in the United States follow SAE J2807?

Yes, by the 2015-2016 model years, all major pickup and SUV manufacturers selling in the United States (including Toyota, Ford, General Motors, RAM, and Nissan) officially adopted the SAE J2807 testing protocol for all published tow ratings.

How does SAE J2807 account for passenger and cargo weight?

SAE J2807 mandates a standardized base testing weight that includes the base vehicle curb weight plus a 150-pound driver, a 150-pound front passenger, and 100 pounds of optional equipment allowance, ensuring ratings do not assume an unrealistic empty vehicle.

What acceleration hurdles must a truck pass under SAE J2807?

When loaded to maximum GCWR on a level grade, the vehicle must accelerate from 0 to 30 MPH in under 12.0 seconds, 0 to 60 MPH in under 30.0 seconds, and complete a 40 to 60 MPH highway passing test in under 18.0 seconds.

What are the parking brake holding requirements under SAE J2807?

The test vehicle and loaded trailer must be parked on a steep 12% grade facing both uphill and downhill. The vehicle emergency parking brake must hold the entire combined weight stationary for a minimum of 5 minutes without rolling.

Does an SAE J2807 rating mean I can always tow that maximum weight?

No. The SAE J2807 rating represents the absolute maximum trailer weight achievable under ideal testing conditions. Real-world passenger counts, heavy truck bed gear, and tongue weight deductions will reduce your vehicle usable capacity before reaching that maximum limit.

How does SAE J2807 evaluate high-speed trailer sway stability?

The vehicle and trailer are subjected to standardized steering pulse inputs at highway speeds. Using onboard yaw rate sensors and lateral accelerometers, engineers measure the sway damping ratio to ensure the trailer naturally stabilizes within two oscillation cycles without driver intervention.

SAE J2807 Towing Standard: How Ratings Are Tested

The Wild West Era of Automaker Towing Claims

Prior to the widespread adoption of SAE J2807 around 2015, advertised towing ratings in the American automotive market were essentially unregulated marketing claims. Ford, General Motors, Chrysler, and Toyota all utilized distinct internal testing criteria.

One automaker might test with a completely stripped regular cab truck containing zero optional equipment, a five-gallon splash of fuel, and a test driver weighing 120 pounds. Another automaker might test on flat closed tracks without testing engine cooling on mountain grades. The result was widespread confusion among consumers who purchased trucks rated for 8,000 pounds only to overheat climbing mountain passes in summer heat.

In response, the Society of Automotive Engineers assembled a committee comprising lead chassis, powertrain, and brake engineers from every major truck manufacturer. The result was SAE J2807: "Tow Vehicle Gross Combination Weight Rating and Trailer Weight Rating Recommended Practice."

The 5 Standardized Testing Hurdles of SAE J2807

To certify a maximum trailer weight rating under SAE J2807, a vehicle loaded to its Gross Combined Weight Rating (GCWR) must pass five mandatory performance hurdles:

Hurdle 1: The Davis Dam Highway Cooling Climb

Thermal Stress Test

The cornerstone of SAE J2807 testing takes place in western Arizona along State Route 68, ascending from the Colorado River near Davis Dam to the Union Pass crest. The route spans 11.4 continuous miles with grades ranging between 5% and 7%, climbing more than 3,000 vertical feet. The test must be conducted in ambient air temperatures of at least 100 degrees Fahrenheit with the vehicle air conditioning system set to maximum cold. To pass, single-rear-wheel trucks must maintain at least 40 MPH and dual-rear-wheel trucks at least 35 MPH without warning lights, engine derating, or fluid boil-over.

Hurdle 2: Acceleration Benchmarks Under Maximum GCWR

Powertrain Performance

On a level paved surface at maximum certified GCWR, the vehicle and trailer must satisfy three strict acceleration thresholds to prove they can merge and pass safely in highway traffic:

0 to 30 MPH: Under 12.0 seconds
0 to 60 MPH: Under 30.0 seconds
40 to 60 MPH Passing Acceleration: Under 18.0 seconds

Hurdle 3: 12% Grade Launch and Park Brake Holding

Transmission & Brake Hold

The fully loaded combination must demonstrate the ability to stop on an extreme 12% highway grade (significantly steeper than standard interstate mountain passes). The vehicle emergency parking brake must hold the entire combined weight stationary facing uphill and downhill for five minutes. Furthermore, the vehicle must launch smoothly from a complete stop five consecutive times within 5 minutes in both drive and reverse gears without transmission slipping or overheating.

Hurdle 4: Braking Performance and Stopping Distances

Braking Deceleration

Braking tests evaluate stopping distance from 20 MPH. For trailers equipped with electric trailer brakes, the combination must come to a complete stop within 35 feet while remaining within a 11.5-foot highway lane without wheel lockup or yaw deviation. Unbraked trailers must stop within 45 feet.

Hurdle 5: Dynamic Highway Handling & Sway Damping Ratio

Lateral Stability

Using steering robots and gyroscopic telemetry, test drivers induce sudden steering wheel inputs at highway speeds. The yaw rate sensors evaluate the sway damping ratio: the trailer must settle back into straight-line tracking within two oscillation cycles without active electronic stability control intervention.

Standardized Vehicle Testing Weight Rules

To eliminate the old trick of stripping vehicles down to unrealistic weights, SAE J2807 specifies that the test vehicle curb weight must include:

Driver Weight Allowance: Certified at 150 lbs.
Passenger Weight Allowance: Certified at 150 lbs in the front passenger seat.
Tow Equipment Allowance: 100 lbs reserved for hitch receiver, ball mount, and wiring hardware.
Fuel Level: Full tank of fuel.
Factory Options: 33% penetration rate allowance for common options (e.g., center consoles, power windows, tow prep).

SAE J2807 Towing Standard Explained