A Weighty Issue

Weight and loading are perhaps the biggest issues affecting the safety, handling and longevity of RVs. But if you’re new to RVing, you’re probably wondering why. After all, there doesn’t seem to be so much concern over weight in a car or even most pick-ups and SUV’s, so why RV’s?

The simple reason is that RV’s are both a vehicle and a home, and they are subject to build considerations not found in any other industry. If you want ideal balance in car, you do things like shift the weight rearward, use lighter components in the front, etc.-and side to side balance isn’t in issue unless your passenger is significantly heavier than you are. In an RV, manufacturers usually don’t enjoy that kind of freedom. Think about what sells an RV. Is it the performance or handling? Nope-it’s the floor plan! Manufacturers have to make an nice floor plan that attracts customers when they walk into the coach on a dealer lot. The problem is, the layout that draws customers in may not be perfect for weight balance. After all, you can’t have the appliances staggered from side-to-side throughout the galley, for example, to keep weight balanced…no one would like your floor plan. Then there’s the placement of the tanks, the generator and the storage bays, and they can all conflict with one another. It’s all about compromise, and some coach builders are better at it than others.

Weight that is poorly balanced can cause a lot of problems in a motorhome. Take overhang, for example. Coach builders want to give buyers as much room as possible, so many resort to rear overhang, where body is extended off of the frame, and supported by a welded-on frame extension. This is a much more cost effective solution than stretching the wheelbase of the chassis, because then you’ve got to deal with lengthening the driveshaft, brake lines, electrical, etc. The problem is, an overhang acts like a lever that pulls the front wheels up, and makes you feel like you’re driving a pick-up with a load of gravel. The coach won’t handle properly, and in many cases we’ve had to add weight to the front of motorhomes to get the balance right. Generally speaking, you want at least 50% of the rear axle’s weight to be over the front axle.

In 1996, the Recreational Vehicle Industry Association (RVIA) introduced a weight labeling program, requiring manufacturers to place weight information on all of their units. This information includes Gross Vehicle Weight Rating (GVWR), Unloaded Vehicle Weight (UVW), Gross Axle Weight Rating (GAWR), Cargo Carrying Capacity (CCC), and other info. This information makes it easier for the consumer to determine if the coach will fit his/her needs, but it still doesn’t tell you how the weight is distributed, whether or not any dealer accessories have been added, and how that weight will affect the ride and handling of the coach.

This is why it is always a good idea to drive the coach you plan to purchase, and compare it to other similar coaches, whether you are considering those or not. Ask the dealer if you can have the coach weighed. Many good dealers have scales on their lots, but if not, ask them if there is a place locally where you can weigh it for yourself. If they are reluctant to help, go someplace else. Good places to check weight include truck stops, dumps and rental yards.

Tell the person who runs the scale what you want to do, so they know what to expect when you drive on. You want to drive the front half on to the scale, get a weight reading, then drive the whole coach on and get another reading. By subtracting the weight of the front from the overall weight, you’ll know what the rear of the coach weighs. Depending on the scale and how it’s laid out, you may also weigh the coach from side to side, but this is an iffy proposition. The aprons on either side of the scale may not be completely level, and this can have an affect on the readings. For one thing, any fluids in the coach, including fuel and water, will shift to one side, affecting the weight distribution. Moreover, we’ve found that weighing coaches side-to-side isn’t particularly accurate, depending on the scale. That’s why at Henderson’s Line Up, we use individual wheel scales so that we can get an accurate picture of how much weight each wheel is carrying. Here is a photo of our wheel scale being used on a fifth wheel:

Take a look underneath and see where the tanks are placed. Are they all on one side, staggered, or centrally located? The coach may feel well balanced now, but that can change once that driver’s side water tank is filled with 80 or 100 gallons of water at 8.3 lbs. per gallon.

If you already own a coach, make sure that you weigh it ready for travel, filled with water, propane and all the supplies you normally bring. If it has a weight or handling problem, the first thing to ask yourself is if there is any way you can shift weight. For example, if you have a motorcycle on a carrier on the back of the coach that weighs 600 lbs. or more-you may want to carry it up front, instead. Move heavy items in the storage compartments forward. And in some extreme instances, as I mentioned earlier, it may be necessary to have weight added to the front of the coach in order to restore balance. Some people don’t like that idea, but the fact is, it’s common practice at the factory level. And as long as there is enough reserve capacity over the front axle, it causes no harm and will make a big difference to the handling.

In the next post, I’ll be talking about another component that affects handling and safety: The tires.