All RVs (both trailers and motorhomes) have two weight ratings. These ratings (numbers) are very important, and it is vital that you know and understand the significance of these ratings when you buy your RV and when you load your belongings and loved ones in them for travel.
GCWR (gross combined weight rating) is the weight of the vehicle when it is completely empty — that means no fuel, no luggage or gear, no food or drinks, and no driver or passengers. GVWR (gross vehicle weight rating) is the maximum weight that the vehicle can carry when fully loaded. The difference between these two numbers is the amount of weight you will be able to load into the rig for travel. You need to figure in everything you will be putting into the RV, and that includes the people, pets, and food you will want to take on your trip and the fuel that you need to power you.
If you are tempted to add too many items or baggage to your rig, you are risking handling problems that could prove dangerous on some roads. You will find that your suspension, brakes, and tires may wear out much sooner than you expected. The damage that causes can be costly, not only in replacing parts that have worn prematurely, but also in the future when you are trying to trade the RV in on a newer rig.
You will usually find the GCWR and the GVWR on a metal plate located inside the door of a trailer for easy accessibility. You should also be able to find them in at least one other location, such as in the engine compartment of a motorhome. A serial number for the unit is likely to be in the same place; this can be useful for verifying with the chassis builder that the weight ratings are correct.
Some RV manufacturers will list GCWR as the weight before optional equipment is added. Air-conditioning units and microwaves will add a significant amount of weight. If the sales brochure lists these items as “optional,” you will need to find out their weights and add them to the GCWR before you can figure out the weight you have available for your gear. If possible, you should try to weigh the vehicle before you purchase it and verify that the ratings are correct. If you are able to get the rig weighed and have to take it to a truck weigh station, remember to figure in the weight of the fuel in the gas tanks (about 6.15 pounds per gallon for gasoline).
Once you have an accurate number for the cargo-carrying capacity of your rig, you will then need to determine the weight of the cargo (you, your passengers, and all the stuff you need) that you plan to carry on your travels. If you want to be safe, you should write down these weights (and weigh things — yes, including yourself — to be accurate). If you find that you are over your weight limit, you will need to start eliminating things.
A smart traveler can pack well within the weight limit of his RV. If your travels will take you though populated areas, don't pack food for more than a day or two and shop along the way. With water, just keep enough in the tank to flush the toilet and carry a small amount in water bottles to drink, restocking as you run out.