Worth the Weight - RV Enthusiast Magazine
Photos by Chris Dougherty
Weighing your RV loaded and ready for travel isn’t difficult, and will net valuable safety benefits
If you’ve done your fair share of research on RVs (in this magazine or others), by now you’ve noticed a reccurring subject: Weight. Regardless of whether you’re shopping for a quad-slide luxury fifth wheel or a simple teardrop travel trailer, weight always plays an important role in the RV you choose, how it is loaded and how much cargo it can safely handle.

Elsewhere in this issue, we’ve touched on the importance of your vehicle’s tow rating and how you can find it, as well as considerations like gross vehicle weight rating (GVWR), gross combined weight rating (GCWR), gross axle weight rating (GAWR), cargo carrying capacity (CCC) and payload. All are important for safe towing, but in most cases, you’ve only got the manufacturer’s figures to draw from. In most instances, that won’t be a problem as long as all of the important figures are within range — but getting the actual weight of your specific tow vehicle/trailer or truck/camper is always a good idea.

For one thing, weighing your rig when it is full of water, propane and all necessary supplies will give you the actual weight of your rig, not the stated base weight. It will also give you the actual hitch or pin weight, which is important when making sure the tow vehicle’s payload and GAWR have not been exceeded. It can even sort out problems you may be having with your individual set-up. Perhaps your trailer suffers from sway at a certain speed, for example, which could indicate there is insufficient hitch weight. Actual weight will help you find out for sure, after which you can shift cargo forward or travel with the freshwater tank (usually located ahead of the rear axles) full, placing more weight on the hitch.

Knowing the actual weight will also tell you how much margin is left before the trailer/tow vehicle is overloaded, which may come in handy on a long trip where you may want to travel with more gear or supplies. Getting your actual weight is just a smart thing to do, and it’s neither difficult nor expensive to obtain.

A CAT weigh station at a gas station
CAT offers a nationwide network of three-platform scales. The company’s website offers a scale locator — catscale.com/cat-scale-locator — to find one near you, and has helpful instructions on how to weigh a tow vehicle/trailer and a motorhome. Photo: Cat Scale
The best way to weigh a vehicle is by wheel position (individual wheel weights), and the RV Safety and Education Foundation (RVSEF) does this for RVers all over the country. However, if you can’t connect with the RVSEF, getting your rig weighed on a truck scale in your community is the next-best option. These can often be found at truck stops, moving companies, landfills and the like — just Google “truck scales” and your zip code or “truck scales near me” and you should be met with a list of nearby scales or, at least, on the way to your next destination. A truck scale will provide overall vehicle weight and — if you can position the vehicle properly — the axle weights as well. With trailers, you can also get front (pin or hitch) and axle weight.
If you’ve never weighed before, a good first step is to park your rig and pay a visit to the weighmaster, the person who monitors and records the weight of each vehicle that crosses the scale. Explain to him/her that you would like to get the overall weight as well as axle weights, and ask if the timing is okay. Depending on the day/time of the week, truck scales can get pretty busy, and you don’t want to feel rushed. The weighmaster may also guide you as to the signals he/she uses to direct a vehicle to move forward and stop in order to get axle weights — some scales have red/green lights while others rely on an intercom system whereby you and the weighmaster can communicate.
2-axle vehicle weigh diagram
The simplest weigh to understand is a 2-axle vehicle like a motorhome. The steering axle is on the first pad, and the rear axle is on the second. This gives you vehicle gross and axle weights. You would use this same method for a truck camper weigh.
Tow vehicle and travel trailer weigh diagram
When towing a travel trailer, your tow vehicle steering axle is on the first pad, drive axle on the second and trailer on the third. To get an accurate calculation for your actual weights while towing, make sure your weight distribution system is properly setup and adjusted before the weigh.
2-axle vehicle with dingy or trailer weigh diagram
Now, add a dinghy or trailer to the motorhome. You will want the dinghy on the third pad. Since the dinghy is supported by its own wheels, this number will help determine that it isn’t too heavy for the motorhome to tow and for the towing equipment to handle.
Tow vehicle and a fiver weigh diagram
As with a travel trailer, weigh the truck and fifth wheel as shown. Because of the added pin weight of a fiver, it is essential to compare the scale weights with each of the ratings for the tow vehicle, including GVWR, GAWR and cargo weight ratings, to make sure none are exceeded with the vehicle loaded (including the kids and the dog) for a trip. Everything. This is the only way to know if you’re over loaded.

Tires and Loading

A load range E tire on a Ford F-350 single rear wheel truck
It’s common not to associate tires with load capacity — for many people, as long as they hold air and still have adequate tread, they are happy. But tires must carry the load safely.

Consider that the tire size and load rating is part of the tow vehicle’s GAWR, which means if the tires are not inflated to the pressure indicated by the tire placard inside the vehicle driver’s side door jamb, the load carrying capacity for the rear axle is diminished. The load range E tire pictured here, which is on a Ford F-350 single rear wheel truck, is rated for 3,640 pounds at 80 psi, which jibes with the truck’s 7,000-pound rear GAWR (two tires at 3,640 = 7,280 pounds).

Generally speaking, it’s always a good idea to keep the tires at the stated maximum inflation pressure for safety’s sake. Manufacturers like Cooper, Goodyear, Michelin and Toyo publish load/inflation tables that can help you determine how much load a tire can carry at reduced pressure, but the concern is that if you only inflate to load and the tire loses pressure (due to a slow leak, for example) it can become overloaded and could fail.

Unlike passenger car tires, where the maximum inflation pressure on the sidewall should never be exceeded, the pressure figure on the sidewall of a light truck (LT) or trailer (ST) tire is the minimum pressure necessary to carry the maximum load. In other words, if a tire reads “Max load single: 3000 lbs. at 65 psi cold”, 65 psi is the minimum cold inflation pressure necessary to carry the maximum load figure.

If the weight of the tow vehicle or trailer exceeds the tire’s ratings, moving up to a higher load range tire (example: from a load range D to load range E) is not the answer. Like tires, rims also have load and pressure ratings — and a tire with a higher load rating can exceed it, possibly resulting in catastrophic rim failure. Always replace tow vehicle or trailer tires with the same size and load rating, keep them properly inflated and use a tire pressure monitoring system to keep tabs on inflation pressure for all the tires (tow vehicle and trailer) while you’re driving.

Lastly, all tires have a speed rating (or default speed of 65 if not stated on a trailer tire) and that speed must not be exceeded. The tire is tested under load at speed to ensure it won’t fail, which is how it gets the rating. Exceeding the speed rating (along with inflation and load) can cause additional heating and the forces on the tire can cause it to fail. If you don’t take your tires for granted, they will almost certainly reward you with reliable, safe performance.

An RV being weighed for safety
A close-up of an RV wheel on top of a scale
A close-up of the weight on the RV displayed on a scale
Weighing by wheel position is the most accurate way to not only determine axle weight, but the weight on each individual wheel. This is important because while an axle may not be overloaded as a whole, one side of the axle may be overloaded if the RV is not correctly balanced. Brazel’s RV in Centralia, Washington (brazelsrv.com) is one company that offers weight by wheel position. A scale is placed underneath each wheel and the weight is recorded on a worksheet, which is provided to the customer.
Truck scales generally consist of separate sections or “platforms” that conform to the axle positions for tractor-trailers, but these will work for tow vehicles with trailers and motorhomes as well. To get the most complete picture, pull your front axle up to the front of the forward most platform. Take a look back at which axles are on the respective platforms: If you’re weighing a tow vehicle and trailer, you will want your front or “steer” axle on platform No. 1 and the drive axle on platform No. 2 on a three-or-more platform system. Your trailer axles should be on the third platform. Your weight report will list each platform as a separate axle, so if you need to adjust your rig on the scale, do so before hitting the intercom button for the final weight numbers.

This first weigh will give you the gross combined weight and axle weights, depending on where the axles fall on the scale. Now, if you’re towing a trailer and want to know its weights, you’ll have to do a second weigh. After the first weigh, tell the operator that you’ll need a second weigh for the trailer. He/she will ask you for company and truck and/or trailer number, so have this information ready. This is to identify you and your equipment at the fuel desk or weight booth. If you are weighing a motorhome, the weigh ticket will provide axle and total weight. There is no need for a second weigh. However, if you’re towing a dinghy it’s a good idea to weigh it, as well, in order to determine the gross combined weight of your rig.

Because you now have the weight of the tow vehicle and trailer, mathematics will allow you to extrapolate the trailer pin or hitch weights by weighing the tow vehicle alone without the trailer. Drive off the scale and drop your trailer in an appropriate parking spot, then proceed back to the scale for your second weigh. Once you’re on the scale, hit the intercom and tell the operator this is your second weigh. This will give you the tow vehicle weight only. Once the operator confirms the weigh, go back and reconnect the tow vehicle and trailer and proceed to the fuel desk to get your tickets.

The first weigh will give you:

  • Gross combined weight (GCW) of the truck and trailer
  • Gross vehicle (GVW) and axle weights for a motorhome.
  • Tow vehicle front and rear axle weights, which will show you the operating weight of the tow vehicle axles. Note: This weigh should be done with weight-distributing equipment in place (if applicable) as you would have it while driving.
  • Trailer axle weight(s).

The second weigh will give you:

  • The truck’s actual weight and individual axle weights without the trailer, but otherwise loaded for travel.

With this information you can determine:

  • The hitch/pin weight of the trailer. Subtract the total tow vehicle weight without trailer from the tow vehicle with the trailer. The difference is the operating trailer hitch/pin weight, since the weigh was with the weight distribution system in place (travel trailers). Fifth wheel trailers will be the actual pin weight.
  • The rear-axle weight of the tow vehicle to determine if it is overloaded
    Remember, the trailer and tow vehicle should be loaded as though you’re going to travel. In fact, you may want to schedule a weight check en route to your next destination. All fuel tanks and cylinders should be full and water- and holding tanks empty.
If the weighing process has disclosed that one or more of the vehicle ratings have been exceeded, then the load should be adjusted to shift weight, if possible. This can be done by reducing cargo or shifting its position; it is not safe to continue operating equipment until the ratings are within range because overloading can have numerous consequences.
Components such as brakes, bearings, universal joints and tires can wear more quickly and may fail prematurely. More importantly, an overloaded motorhome, tow vehicle and/or trailer can create a hazard for yourself and other drivers. Overloaded tires can blow out, brakes can fade or fail, or more serious structural components can break — which can all lead to loss of vehicle control at speed and cause a crash.

As eluded to earlier, the one value you won’t get by weighing at a public scale is weight by wheel position. While it may be possible to have the vehicles half-on the scales in some truck scales to weigh each side, it is generally not possible to do this. The best possible weighing scenario is to have the RV weighed by wheel position; this is how the RVSEF weighs RVs at the events they attend. For information on events near you, visit https://www.rvsafety.com/schedule. If this doesn’t work for you, contact a local RV or heavy-truck repair center in your area to see if it can weigh your rig by individual wheel position. RV forums are another good place to network with other enthusiasts who may be able to help locate a shop with wheel scales. Also, there’s a smartphone app called RV Tow Check which helps with the process.

Tire and Weight Analysis Worksheet from Brazel's RV Performance
Here you can see why weighing by wheel position is important. This customer’s Thor Axis Class A, which is based on a Ford F-450 chassis rated at 12,500 pounds, is pretty well balanced — but it’s overweight by 300 pounds. The excess weight should be removed.
Obviously, anything added to an RV increases its weight, but it can be easy to underestimate not only the added weight but also its impact on a specific location. Many RVs come prepped for items like a satellite dish, a second air conditioner and a washer/dryer — all of which add considerable weight. Aftermarket accessories like solar panels and battery banks may not seem like much, but if the RV is already near its limit these accessories can also contribute to an overloaded condition. Then, of course, there are heavier items that some RVers like to bring along, like a motorcycle or a pair of kayaks and the related gear.
This is where weighing by wheel position is important. While an RV may be within its weight rating for a particular axle, it’s possible for one wheel position to be overloaded depending on how the RV is balanced and how it is loaded. With individual wheel weights, it may be possible to shift weight to improve handling/stability.

We all want our RV experiences to be safe, enjoyable and as economical as possible. Paying attention to tow vehicle, trailer and motorhome weight at the beginning of a trip — and making sure you don’t add weight later or pick up too much weight while on the road — will go a long way toward that goal.

Did You Know?

If you find a CAT or multi-platform scale on a quiet day and no one is waiting for the scale, you may be able to get trailer pin or hitch weights while on the scale, but do not hold up a line of trucks to weigh your rig. Pull your tow vehicle slightly ahead until the rear axle of the tow vehicle is off the scale, the trailer jack(s) are on the front pad and the trailer wheels are on the second. Now, use the jack(s) to just raise the trailer enough to remove the weight from the hitch (easier on a fiver) and ask for a second weigh. This will give you the actual hitch/pin and axle weights as well as the GVW for the trailer.

Weighing a Pickup Camper

A pickup camper at a CAT weigh station
Slide-in truck campers are a popular solution for those RVers who like to camp off the grid and have the freedom to park just about anywhere. Depending on the size and how they are equipped, however, they can quickly overload a truck.

If you’re shopping for a camper, keep in mind that these also have a label that lists the camper’s base weight (no additional options) with water and propane on board. Make sure that this figure does not violate the stated maximum payload and GVWR of the truck, and remember that maximum payload includes passengers as well as all cargo you normally bring in the truck — not just how much it can carry in the bed.

Truck camper labeling does not list GVWR (because it’s not a vehicle), so determining the weight when it is loaded and ready for travel is on you.

If the camper has optional equipment like an A/C unit, generator or larger refrigerator, those must be added to the stated base weight. The manufacturer should be able to help determine additional weight based on optional equipment.

When weighing a truck/camper combination, start with the truck by itself, full of fuel and anything you would normally carry in it for a trip, including passengers.

If you already own a camper, load it on the truck, again filling the freshwater tank and loading the stuff you would ordinarily bring on a trip. Repeat the process above with the camper onboard to ensure the payload, GVWR and GAWR have not been exceeded. If you are overweight by a few hundred pounds, reconsider what you normally bring, or travel with the freshwater tank at, or nearly, empty if possible.

Campers are popular because they give you the freedom to tow a dinghy vehicle, boat or utility trailer. If you are going in that direction, it’s important to take the trailer’s weight and hitch weight into consideration, and make sure the tow rating and GCWR aren’t exceeded.

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