Most people can easily determine when they're adding a little too much cargo weight to the family vehicle. For example, let's just say you were at the local home improvement warehouse store shopping for new ceramic tile. If you were to load box after box of ceramic tile to the cargo area of your hatchback subcompact car, it wouldn't take very long for you to realize that you were overloading the rear suspension. In fact, after loading just a few of the heavy boxes of tile into your car, you'd likely see that your rear bumper is noticeably closer to the pavement and your front bumper is moving upward just as quickly. In this case, it's very easy to establish that your small car is just not designed to carry that much weight.
Even if you had a pickup truck or SUV, there's a good chance that you might still see similar results. Of course, it would take a lot more weight (in this case, several more boxes of tile) to make the back end of a pickup truck or SUV sink like that because they're designed to carry much more cargo weight.
Now imagine that you were loading those boxes of tile into a massive recreational vehicle (RV). Unless you purchased an abnormally large amount of tile, you really wouldn't even know that the boxes of tile were there unless you actually looked inside. The reason is because some of the really big RVs are designed to carry a lot of cargo weight.
So how would you ever be able to determine if you were overloading an RV? After all, recreational vehicles carry things like furniture, appliances, televisions and people -- often lots of people. How much is too much? The short answer is that you would need to know the RV's cargo carrying capacity, or CCC. The long answer involves a little bit of simple math and a few definitions. Here's how to calculate an RV's cargo carrying capacity:
- Start with the vehicle's gross vehicle weight rating (GVWR)
- 20,000 pounds (GVWR)
- Subtract the vehicle's unloaded vehicle weight (UVW)
- The UVW is a manufacturer provided weight measurement of the vehicle that includes a full tank (or tanks) of fuel, coolant and oil
- 14,500 pounds (UVW)
- Subtract the weight of the sleeping capacity weight rating (SCWR)
- The SCWR is another manufacturer provided weight measurement (a maximum weight) determined by multiplying 154 pounds times the number of sleeping positions
- 924 pounds (SCWR) (6 sleeping positions x 154 pounds)
- Subtract the weight of the propane fuel (LP gas)
- Propane weighs 4.2 pounds per gallon
- 50.4 pounds (LP gas) (12 gallons x 4.2 pounds)
- Subtract the weight of the fresh water on board
- Water weighs 8.3 pounds per gallon
- 207.5 pounds (fresh water) (25 gallons x 8.3 pounds)
- The result is the cargo carrying capacity (CCC) of the vehicle
- 4,318.1 pounds (CCC) (cargo carrying capacity)
It's important to understand that the cargo carrying capacity definition, as outlined for you here, is a weight limit, or maximum weight, as determined by the vehicle's manufacturer. For safety's sake, the RV CCC should never be exceeded.
If you're curious about your own vehicle's cargo carrying capacity, the manufacturer should be able to provide you with this data. Another option is to search for the information on the Internet. Most manufacturers will publish this and other important vehicle information online.
The chart on the next page may be helpful, too.