Determine RV's Correct Weight
The GVWR (Gross Vehicle Weight
Rating) and GAWR (Gross Axle Weight
Rating) stickers on your motorhome (normally located on the support pillar next to the driver's seat) will show you the chassis manufacturer's and/or the motorhome manufacturer's total vehicle maximum weight ratings and per axle
The GVWR is the maximum total weight for which the vehicle is rated - including passengers, fluids, and cargo. The GAWR is the maximum for which a single axle
is designed. These per axle and total maximum weight ratings could be limited by the tires
, wheels, axle and axle bearings, springs, the vehicle frame, or other components of the vehicle.
The GAWR sticker is only a guide in knowing your maximum loaded axle weights and subsequently your correct tire inflation pressure. Every motorhome, even of the same make and model, will vary in actual loaded axle weights, because of different options and personal loads.
While your actual, loaded axle weight should be below the GAWR, you must weigh your motorhome in a loaded condition to know its actual weight. Weigh the front axle, the total unit, and then the rear axle. It is possible for a vehicle to be within the GVWR yet overloaded on an axle. It is even possible for one wheel position to be overloaded, even though the GAWR has not been exceeded. For this reason (if there is room to the sides of the scale) Michelin recommends weighing
each wheel position of the vehicle. This will give you a clear indication of exactly how the weight of your motorhome is distributed. The Tire Industry Safety Council publishes a "Recreational Vehicle Tire Care and Safety Guide" which includes instructions on how to weigh your vehicle by wheel position.
Links to selected instructions and diagrams are presented here: Weighing
Your Single Axle Recreational Vehicle or Weighing
Your Tandem Axle Recreational Vehicle. Print the correct diagram/instruction from the links for your type of RV and use in conjunction with the "How to Weigh Your RV" section found below.
Where to Weigh Your Vehicle
There are probably several certified public scales in your area. You will find public-access scales in a variety of places, such as moving and storage company lots, farm suppliers with grain elevators, gravel pits, recycling companies, and large commercial truck stops.
If you are not aware of a nearby public scale, check your phone book's yellow pages under "scales-public" section or "weighers". A nominal fee will be charged, but this is money wisely spent.
How to Weigh Your RV
Your RV must be weighed fully loaded, that is, with passengers, food, clothing, fuel, water, propane
, supplies, etc. Any towed vehicle (car/pickup, boat or trailer) or item loaded on brackets on the back of the RV, such as bikes or motorcycles, should also be included in the weighing.
There are three types of scales: 1. Platform. 2. Segmented Platform. 3. Single Axle.
1. The platform scale is long enough to weight the complete vehicle.
2. The segmented platform scales can provide individual axle weights and total vehicle weights simultaneously, when the vehicle is positioned properly.
3. Single axle scales weigh one axle at a time.
1) The platform scale is long enough to weight the complete vehicle. The following steps are suggested and are illustrated with diagrams found in the above links under "How to Determine Your RV's Correct Weight".
a) Pull onto the scale so that only the front axle is on the platform (with the end of the scale midway between the front and rear axles), and record the scaled weight.
b) Pull forward until the full unit is on the scale, and record the scaled weight.
c) Pull forward so that only the rear axle is on the scale (again with the edge of the scale midway between the front and rear axles), and record the scaled weight.
d) If the RV has a rear tag axle, pull forward so that only the tag axle remains on the scale, and record the scaled weight.
If there is no towed vehicle, this weight will represent the actual weight on the tag axle. To determine the actual load on the rear axle, subtract this value from the recorded weight in step 1c. If there is a towed vehicle, proceed to step 1e (see link above for "Weighing Your Tandem Axle Recreational Vehicle"), to obtain the "towed vehicle only" weight. Subtract that value from the value above and then subtract that from the weight recorded in step 1c.
If a boat, trailer or other vehicle is being towed, it should be weighed and combined with the towing vehicle's GVW (Gross Vehicle Weight) to ensure the total weight does not exceed the GCWR (Gross Combined Weight Rating).
2) The segmented platform scales can provide individual axle weights and total vehicle weights simultaneously, when the vehicle is positioned properly.
Position the vehicle on the scales so that each axle is centered as much as possible on separate segments, and record the weight. Reposition the vehicle so that only one side is on the scale, again centered on the segment as much as possible. Subtract the weighed wheel positions from the total axle weights to determine the unweighed wheel positions' weights.
3) The single axle scale weighs one axle at a time.
Drive your front axle onto the scale and stop long enough for the weight to be recorded. Pull vehicle forward until the rear axle is on the scale. To obtain the gross vehicle weight add the two axle loads together. To obtain the individual wheel position weights, repeat this process with only one side of the RV on the scale.
Note: Even though the weight of the total axle may be within the axle's rating, it may be overloaded on one side. This causes one wheel position to be overloaded. Therefore, side-to-side weighing should also be done.
To determine individual wheel position weights, it is necessary to repeat the previous three steps (1a, 1b and 1c), but this time, use only one side of the scale, as shown in the diagrams (see links above)
To calculate the opposite side of the vehicle wheel position weight, subtract this side's weight from the weights recorded in steps 1a, 1b and 1c.
Your RV must remain as level as possible on the scale (even though an axle or side is not physically on the scale). Obviously, to obtain the side-to-side weights, there must be enough space on either side of the scale to accommodate the RV being partially off the scale.
If there is a difference in the weights on one side of the vehicle as compared to weights on the other side, components (tires, wheels, brakes
, springs, etc.) on the heavier side could be overloaded, even though the total axle load is within the GAWR. It is important to redistribute the load to avoid component failure, as well as to improve the handling characteristics of the vehicle. With these actual weights, it is now possible to compare them against the GAWR, GVWR and tire capacities. These weights are also what should be used to help determine the proper air pressure for the tires
If you are towing a vehicle or trailer, you need to know your RV's GCWR (Gross Combined Weight Ratings). This is the total actual loaded weight of your RV (or tow vehicle) plus total actual loaded weight of the towed vehicle (or trailer). The total actual loaded weight of the RV and towed vehicle should not exceed the GCWR. While the GCWR has more to do with the drivetrain (engine, transmission, axle, brakes
, and bearings) design limits, this additional weight can also affect the tires
and how your RV (or tow vehicle) handles. And finally, please don't forget to consider the tongue weight of the trailer.