Whether you’re towing a trailer or hauling a load in your truck bed, knowing how much weight your vehicle can handle is essential. Overloading your car, truck, or SUV can damage the axles, transmission, and even your vehicle’s frame. Not only that, but it can cause serious safety issues, both for you and for other drivers on the road.

Today, we’re going to talk about how to determine your vehicle’s maximum payload. We’ll be focusing specifically on trucks because they’re the obvious choice for towing and hauling. The same principles apply to cars, SUVs, and any other motor vehicle.

To determine your vehicle’s maximum payload, you first need to know the gross vehicle weight rating (GVWR). The GVWR is your car's maximum total weight, including cargo, passengers, etc.

Finding your GVWR is simple. Most modern trucks have a sticker on the driver’s door jamb with the GVWR and other essential data. If there’s no sticker on your vehicle, you’ll be able to look up the GVWR in your owner’s manual. Most vehicle models come in different variants, so you’ll need to look up the correct variant.

In the US, trucks are categorized into different weight classes. Class 1 trucks are the lightest, with a GVWR of 6,000 pounds or less. Class 8 trucks are the heaviest, with GVWRs of 33,000 pounds or more.

Your vehicle’s curb weight is the weight when empty. This includes a full tank of gas and full fluid reservoirs but no passengers or cargo. Knowing your curb weight gives you a baseline for determining how much you can haul. Subtract your curb weight from your GVWR, and you know how much weight you can load into the vehicle.

The gross combined vehicle weight rating (GCVWR) is the maximum weight of your vehicle and trailer together. In most cases, this will be higher than the GVWR because you can tow a heavier load than your truck bed can accommodate.

This is because the bulk of a trailer’s weight rests on the trailer’s axles, not on your vehicle’s. Instead, GCVWR is mainly constrained by your brakes. Even if you can pull a load, you still need to be able to come to a stop safely.

Tongue weight is the portion of your trailer’s weight supported by the tow hitch rather than your axle. Depending on the trailer's design and how it’s loaded, tongue weight can be between 10 and 15% of the total weight.

The tongue weight can differ between two vehicles of the same model if they have different tow hitches. For example, a Class II hitch has a maximum tongue weight of 525 pounds, regardless of whether the vehicle can support more. The same vehicle with a Class III hitch could support up to 800 pounds of tongue weight.

If you exceed your vehicle’s GVWR, you can damage your vehicle's transmission, suspension, and other essential parts. Towing a trailer that’s too heavy can be even more dangerous. For instance, you might not be able to stop in time for a red light and be forced into the middle of a busy intersection.

Calculating your vehicle’s maximum payload is straightforward. You take the GVWR and subtract your vehicle’s curb weight. The remainder is your total maximum payload. Remember that this doesn’t just mean the weight of whatever is in your truck bed. It also includes the passengers. If you’ve got five 200-pound people in the vehicle, that’s 1,000 pounds of payload!

Suppose your truck has a curb weight of 5,000 pounds, with a GVWR of 7,500 pounds. You would calculate as follows:

So your maximum payload would be 2,500 pounds.

When you’re hauling a trailer, things get a little more complicated. Remember, the trailer weight counts towards the GCVWR, not the GVWR. However, the tongue weight does count towards your GVWR. It’s best to assume that your tongue weight is heavier rather than lighter. Count 20% of your trailer’s weight towards the payload, and you’ll have plenty of margin of error.

Determining your towing capacity is similar to determining the payload capacity. However, instead of using the GVWR as a baseline, you’d use the GCVWR. Let’s use our earlier example of a 5,000-pound truck with a 7,500-pound GVWR and assume it has a GCVWR of 12,500 pounds. In this case, we would calculate:

So you would have a towing capacity of 7,500 pounds.

However, things aren’t always that straightforward. You also have to account for the weight of passengers and cargo. Even if you’re the only person in the truck and weigh 150 pounds, your actual towing capacity would be 7,350 pounds. If you had 2,000 pounds of gravel in your truck bed, the weight would reduce that to 5,350 pounds.

Often, truck manufacturers will inflate their advertised maximum payload. This isn’t to say they’re lying, but they can often stretch the truth like many advertisers. For example, a truck might be rated to tow 5,000 pounds, and the frame might technically support that, but you could have poor acceleration and braking.

The Society of Automotive Engineers (SAE) has a standard called SAE J2807. This standard puts trucks through a series of towing tests and determines a more realistic weight rating. For this reason, it’s wise to look for third-party ratings rather than relying solely on the manufacturer’s documentation.

Your vehicle’s maximum payload equals the GVWR, minus the curb weight. On the other hand, Towing capacity is equal to the GCVWR minus the curb weight. Thankfully, both numbers are easy to calculate so that you can travel safely and reliably.

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© 2022 J.D.Power. All rights reserved.

© 2019 J.D.Power. All rights reserved.