How Payload Works

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Calculating payload capacity requires you to know your vehicle's GVWR (gross vehicle weight rating) and curb weight.

So how are you supposed to know how much payload you can afford to carry in your car or truck? To calculate your vehicle's payload capacity, you only need to know two things: your vehicle's gross vehicle weight rating (GVWR) and its curb weight.

Gross vehicle weight rating is simply the maximum allowable weight of an entire vehicle when it's packed up and ready to go -- that includes the weight of the vehicle itself, all of the necessary fluids for operation (gasoline, diesel, oil and so on) and any cargo, passengers and tools. A vehicle's GVWR is calculated by its manufacturer, and you can typically find it in your owner's manual or on the vehicle's doorframe, near the door latch. You might also find your vehicle's GVWR on Web sites that list these numbers.

Curb weight is simply how much the vehicle weighs on its own, without any cargo or passengers. This measurement includes a full tank of gas and any other fluids that keep a car running.

So, a vehicle's payload capacity -- the amount of stuff it can safely carry after you've filled up the tank with gas and topped off all of the fluids -- is just a matter of subtraction.

Gross vehicle weight rating - curb weight = payload capacity

For example, if you have a car with a GVWR of 3,500 pounds (1,588 kilograms), and its curb weight is 3,000 pounds (1,361 kilograms), you would subtract 3,000 pounds from 3,500 pounds.

3,500 pounds (GVWR) - 3,000 pounds (curb weight) = 500 pounds (227 kilograms) of payload capacity

Do you need to take into consideration whether your vehicle's a car, truck or SUV? Read on to find out.

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Your truck's payload is going to be much heavier than other types of vehicles, so knowing how the truck is classified will help you determine what amount is safe.

What you consider payload for a truck is going to be considerably different than what you carry in a car or SUV. You probably wouldn't carry long wooden boards for your house's reconstruction inside a small station wagon. At the same time, chances are you don't need a big, heavy-duty truck to move a few bags of groceries.

For the most part, a truck's payload is typically going to consist of heavier cargo. It's important to note that trucks in the United States are classified according to their maximum gross vehicle weight rating. There are actually two ways we can look at this: by class or by category, although both are related to each other. Weight classes, determined by the U.S. government, divide maximum truck GVWR into eight clas­ses:

The U.S. Department of Transportation (DOT) also groups these classes into broader categories. Classes one and two are considered light-duty trucks, classes three through five are medium-duty trucks, while everything in class six and above is classified as a heavy-duty truck. Knowing where your truck falls within these categories will make it easier for you to determine how much payload you can afford to carry during your trips.

On the next page we'll take a look at how much you should be able to carry in your car.

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Chances are this guy is exceeding his payload capacity for his car.

Most of us who drive a car don't think as seriously about payload as someone who drives a truck. After all, a father wouldn't normally ask "Well, do we have the necessary payload packed up?" once his wife, children and luggage are settled into the car for a long drive. Compared to a truck, a car's payload is typically going to be much lower. Some of the car's load may be heavy, but anything that's heavy enough to exceed payload limits and be considered dangerous probably won't fit in a car anyway.

Still, there are some important things to consider when loading up a car that can affect your planning and the ease of a trip. It helps to remember that passengers count as payload, too, and that most car manufacturers factor in 150 pounds (68 kilograms) per person per seating position. That means that when you're considering how much weight you can carry in your car, you can think about every available empty seat as an extra 150 pounds. For instance, if your back seat that's designed to carry three passengers is empty, then you essentially have 450 pounds (204 kilograms) to fill up before things get a little shaky.

An SUV can carry far more weight than a car, right? On the next page we'll see how payload works for these vehicles.

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An SUV can carry more than a car, but if you treat it like a truck you might run into some safety issues.

When it comes to payload, some think of an SUV as a sort of best-of-both-worlds vehicle -- it has lots of carrying capacity like a truck, but it also has the seating capacity and other luxuries of a car.

It's best to think of the payload capacity of an SUV as in between a truck and a car. Usually it can carry more than a car can. It's easy to make extra space in most SUVs because the back seats almost always have the capability of folding forward, creating one large storage space that can carry some extra-large cargo -- gear that's a bit more heavy-duty.

Unlike most pickup trucks, of course, SUVs have roofs, so there's a limit to how much you can pile up. But more importantly, you wouldn't want to treat your SUVs payload capacity like a truck's anyway because of safety issues. Even though the perception of SUVs is that they're great for carrying cargo and have on-and-off road capabilities, many also view them as potentially dangerous. Because the center of gravity on an SUV is typically much higher than a car's, they're much more likely to roll over, especially once they're overloaded.

Many SUV manufacturers, responding to consumer fears, have developed safer vehicles using electronic stabilizing technologies. Concern over accidents has led to safety legislation, too: Since September 2004, the National Highway Traffic Safety Administration (NHTSA) requires manufacturers to place a label that states the maximum combined weight of all occupants and cargo on the doorjambs of all vehicles with a GVWR of less than 10,000 pounds (4,536 kilograms) [source: Kurczewski].

So what if you need to haul something particularly heavy? Can you increase your payload capacity? On the next page, we'll find out.

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If you're ever thinking about increasing a vehicle's payload capacity, that vehicle's manufacturer probably offers a towing package that can upgrade certain working parts and add special tools.

Knowing your vehicle's payload capacity is great, but what if you wanted to carry even more? Is that possible? What if you see a truck you really want, but its payload capacity isn't enough?

Truck manufacturers almost always offer optional towing packages for their vehicles. What's in these packages can vary from one company to the next, but they typically increase the performance of the tow vehicle and include extra tools for better towing. For instance, a truck with a towing package might come with a trailer wiring harness, a heavy-duty hitch and safety chains. The manufacturer might also install a bigger engine, stronger brakes and a better cooling system for overall increased performance.

Remember, overloading a vehicle with too much payload is a dangerous situation, one that can harm you, your passengers and other drivers. If a police officer pulls you over and determines that your vehicle is overloaded, it's possible that you may get a ticket for unsafely loading a vehicle -- something no one ever enjoys.

Depending on the make and model year of your car or truck, you may be able to find your vehicle's payload on the following chart.