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How RV Towing Safety Works

RV Weight Safety
Never exceed your vehicle's weight limits -- and don't forget to properly balance the load, too.
Never exceed your vehicle's weight limits -- and don't forget to properly balance the load, too.
Kent Weakley/iStockphoto

Some of the most serious problems that can occur when using an RV for towing, or when towing a fifth wheel Page SavedRV, can be prevented simply by knowing the your vehicle's weight capacities or weight ratings and acting accordingly. Every RV has a manufacturer-recommended carrying capacity -- and exceeding it is asking for trouble. Let's define some terms that will help us better understand RV weight safety:

­Tongue Weight is the weight that a towed trailer places on the tow vehicle's hitch.

Gross Vehicle Weight Rating (GVWR) is the maximum weight that the vehicle can safely carry, including its own weight plus the weight of any fuel, oil, water, cargo, passengers and the tongue weight of any trailer being towed. GVWR is calculated by the manufacturer and should be discussed with you when you purchase the RV. In many cases, the GVWR of an RV is clearly displayed on a placard somewhere inside the RV.

Gross Axle Weight Rating (GAWR) is the maximum weight that should be placed on any single axle of a tow vehicle or trailer, as measured at the wheel.

Dry Weight is the weight of the RV without any fuel, water, oil, coolant, cargo, or passengers.

Gross Combined Weight Rating (GCWR) is the combined weight-carrying capacity of a tow vehicle plus its trailer.

Curb Weight is the weight of the RV with fuel, water, oil and coolant, but no passengers or cargo.

Net Carrying Capacity (NCC) is the total weight that an RV can carry, including cargo, passengers and trailer tongue weight. NCC doesn't include the weight of the vehicle itself and can be calculated by subtracting the vehicle's curb weight from the GVWR.

Once your vehicle is fully loaded, how do you go about finding out how much your tow vehicle and trailer weigh? Some truck stops have large public scales that you can use for a small price. Look in the phonebook under "Public Scales" or "Scales, Public" to see if any are available in your area. You can also use these terms to search the Internet to find nearby scales.

You should never attempt to carry more weight than your RV is rated for -- and remember, the weight you're adding to your RV includes the tongue weight of any trailer or other vehicle being towed. You may be tempted to ignore the weight limit because overloading a vehicle doesn't necessarily cause any immediate problems. But over time, the extra weight can literally destroy the suspension, the brakes, the frame, the tow hitch, the engine and any other parts of the vehicle involved in carrying, moving (or stopping) that weight. Furthermore, the excess mass gives the vehicle a dangerous amount of inertia -- giving your RV the tendency to keep moving even when you don't want it to. Imagine that you're towing a fifth wheel RV down a hill and need to slow down or stop. Your tow vehicle's brakes might be overwhelmed by the excessive weight -- and even if the brakes do work properly, it will take you a great deal longer than usual to stop. The result could be a serious accident, damaging not only your RV but other vehicles, too; not to mention the personal injury you may cause to yourself, your family and other bystanders.

Also, when going uphill you might find that you simply can't reach the top, or that you can reach the top only at the expense of straining the engine, which can lead to costly repairs. Or you might just find yourself far from home with damaged tires and a faulty suspension -- that's enough to ruin any vacation.

Even if you keep the vehicle's weight within appropriate limits, it's also important to distribute the weight for proper balance. Not doing so can affect your ability to control the vehicle including loss of steering control, reduced braking effectiveness and even an increased chance of trailer sway in some circumstances. Experts recommend not only keeping weight evenly distributed from side to side but from front to back, too. The tongue weight of a trailer should be between 10 and 15 percent of the total weight of the loaded trailer. Fifth wheel hitches can accommodate much heavier weights at the tongue -- often as much as 25 percent of the trailer's weight. One critical point to remember when loading up any tow vehicle or trailer -- don't forget to maintain the proper axle weights, based on the GAWR.

Up next, we'll take a look at a basic RV towing safety checklist. Read the next page to find out if you're prepared for that cross-country road trip.