What Is Gross Combined Weight Rating And Why Is It Important?

The gross combined weight rating (GCWR) represents the maximum combined allowable weight of a tow vehicle and its trailer when both are fully loaded. The GCWR is determined by the vehicle manufacturer. It includes the weight of:

• The vehicle
• The trailer
• Passengers
• Fuel
• Cargo
• Tongue weight

The vehicle manufacturer sets the gross combined weight rating based on the engine output, braking capacity, axle ratios, and overall structural strength. 

The GCWR is measured by adding the gross vehicle weight (GVW) with the gross trailer weight (GTW) with the trailer fully loaded.

Below is a visual illustration from Ford’s Towing Guide.

What Does the Gross Combined Weight Rating Mean?

The gross combined weight rating is typically established using a testing standard like SAE J2807, which evaluates acceleration, maintaining safe highway speeds on inclines, and braking distance. 

It specifically means that a vehicle has been specifically engineered to operate under safe conditions when carrying less than the absolute GCWR limit. At or above the GCWR, you are placing more strain on the vehicle’s components than it was designed to safely handle.

Why Does GCWR Matter?

The GCWR matters because it represents the maximum limit of what a towing vehicle is engineered to safely handle. Every component of a vehicle is created and tested based on a set weight ceiling.

When you keep your vehicle and trailer load below capacity, it helps ensure your vehicle handles safely and has the power to perform within safe driving limits. This includes the impact on your drivetrain, steering response, and overall control on the road.

Measuring the GCWR is important because measuring GVWR and towing capacity alone aren’t enough to be completely safe on the road. Without factoring in passengers, cargo, fuel, and tongue weight, you may think you’re at a safe towing capacity when you’ve actually gone over the limit.

What’s the Difference Between GCWR vs. GVWR vs. Towing Capacity?

GCWR, GVWR, and towing capacity each define specific safe limits of a towing setup:

• GCWR (Gross Combined Weight Rating): The maximum weight limit of the fully-loaded tow vehicle and trailer combined. The purpose of knowing the GCWR is primarily to protect the vehicle’s handling, powertrain, and braking system.
  
  
• GVWR (Gross Vehicle Weight Rating): The tow vehicle’s maximum weight when it is fully loaded. This includes the vehicle’s base curb weight, passengers, fuel, cargo, tongue weight, and any accessories. The GVWR’s purpose is to advise regarding the vehicle’s weight limit in order to protect the frame, axles, suspension, brakes, and tires.
  
  
• Towing Capacity: The GCWR minus the loaded weight of the tow vehicle. Towing capacity is the maximum trailer weight a vehicle is designed to pull, assuming an empty vehicle. 

GCWR vs. GVWR vs. Towing Capacity Compared

How Do I Know If I’m Exceeding My GCWR?

The most reliable way to know if your setup exceeds the GCWR is to measure your actual load and compare it to the manufacturer’s GCWR.

A public CAT scale is the most accurate measurement system. Pull the fully loaded truck and trailer onto the scale, with driver, passengers, fuel, cargo, and gear. By adjusting the position to measure the vehicle alone (GVW), the trailer alone (GTW), and the two combined (GCW), you are able to compare the GCW to your GCWR to see if the setup is within the limit.

Where Do I Find My GCWR?

Most tow vehicles will list the GCWR under specifications, along with towing capacity and payload details. Manufacturers will also typically publish a dedicated towing guide for each model and year, since the GCWR depends on the exact engine, trim, axle, ratio, and drivetrain.

Best Practices: How to Stay Within GCWR

Your tow vehicle’s GCWR is a fixed number set by the manufacturer, but the actual weight of your loaded setup changes every trip. The following best practices help you be sure your load remains below the GCWR limit:

• Check your payload capacity. Subtract the vehicle’s curb weight from its GVWR to get the available payload.
• Use a public CAT scale for an accurate read of your GVW, GTW, and GCW, so you know the weight of your fully loaded setup.
• Plan around your vehicle’s actual loaded weight, including fluids, gear, and cargo.
• Keep your tongue weight between 10% and 15% of the loaded trailer’s total weight.
• Look into using a built-in scale tongue weight hitch, which lets you read your tongue weight before pulling out, keeping your payload and the combined setup within their rated limits.
• Position around 60% of your cargo weight ahead of the trailer’s axle and 40% behind it to keep the tongue weight within the safest range.
• Consider that the manufacturer’s towing capacity assumes an empty vehicle with the driver only. If you have passengers, tools, or other equipment, this should all be factored into your vehicle’s total capacity.

Know Before You Tow with Weigh Safe

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