Weight
Weight is something we may worry about personally but don’t pay much attention to with our vehicles. Believe it or not, there IS a limit to how much you can safely carry.
This is not how we travel, but they might benefit from doing some of the calculations below.
RVers must be aware of weight capacity and the actual weight of their rigs. This section explains the importance of the numbers and how to find out if you’re within limitations. I’ll use the data for our truck and fifth wheel in the following examples:
Tow Vehicle - 2016 Ford F-350 King Ranch 4-wheel drive (4x4), 4-door (CrewCab), Long Bed (LB), Dual Rear Wheel (DRW) with a 6.7 Liter Powerstroke Diesel engine
Fifth Wheel - 2015 Redwood 38RL
your truck SPECS
The sticker on the driver’s side door post is the official manufacturer’s specification for my vehicle. Modifications like air bags, heavier springs, changing the axle ratio, etc. might actually increase the weight capacity of the truck but doesn’t do anything to officially change the certification of the vehicle by the manufacturer.
The Gross Vehicle Weight Rating (GVWR) is the maximum weight capacity of the truck - not the amount you can load in the back or the amount you can tow, but the maximum weight for the truck including fuel and passengers.
The Rear Gross Axle Weight Rating (GAWR) is the maximum load for the rear axle.
What the sticker tells me:
Gross Vehicle Weight Rating - 14,000 lbs.
Rear Gross Axle Weight Rating - 9,650 lbs.
The Axle Code is 3L, which I’ll need to find out my axle ratio.
Next, I check the specifications on the truck tires. This information is easily available on the internet - just Google your brand and tire size.
Each tire on my truck has a load capacity of 3,195 lbs. at 80 psi.
3,195 x all 4 rear tires = 12,780 total load capacity on rear tires
I compare the tire load capacity (12,780) to the rear axle weight rating (9,650). This tells me that my tires will handle any load on the truck as long as I don’t exceed the Rear GAWR.
I Googled “2016 Ford Truck Towing Specs” and found the 2016 RV and Trailer Towing Guide, published by Ford. The charts show me the factory towing specs for each model of truck made in 2016 combined with towing any type of trailer. These charts are thorough, but you have to make sure you’re looking at the correct data.
The guide tells me a “3L” axle code is a 3.73 ratio.
For my truck, engine and axle, the chart shows valuable information:
How much can this truck safely haul? Maximum loaded fifth wheel trailer weight - 23,500 lbs.
What is the maximum safe weight for the truck and fifth wheel trailer combined? Maximum combined vehicle weight - 32,100 lbs.
Summary of Truck Specs:
GVWR - 14,000 lbs
Rear GAWR - 9,650 lbs
Combined vehicle weight rating - 32,100 lbs
Maximum trailer weight - 23,500
Now I can move on to the Fifth Wheel…
Fifth Wheel Specs
Every trailer is required to have a manufacturer decal similar to this. It’s wise to take a picture of your decal because they will fade over time.
Here’s the data obtained from this sticker:
GVWR - 16,500 lbs
GAWR - 7,000 lbs per axle
Tire size - 215/75R17.5H
Cargo carrying capacity - 1,687 lbs (I used Google to convert kg to lb) with fresh water tank full and waste tanks empty
An important note: I upgraded the 7,000 lb axles/springs to 8,000 lb. This gives me an extra 2,000 lb capacity even though not reflected by the factory decal. Even after suspension upgrades, the factory decal cannot be changed. The decal reflects the standards that the rig was certified to meet when it was manufactured.
I looked up the load capacity of the tires I have on the Redwood. According to the chart, this tire on a tandem axle (2X) has a load capacity of 4,540 lbs., or 9,080 lbs. per axle.
Summary of Fifth Wheel Specs:
GVWR - 18,500 lbs
GAWR - 8,000 lbs per axle (16,000 lbs total)
Tire Load Capacity - 9,080 lbs per axle (18,160 lbs total)
Now to weigh the truck and trailer…
Weighing Your Rig
Weighing your rig for the first time can be intimidating. Here’s how you do it.
Find a truck stop with CAT Scales.
Fill up your fuel tank.
Pull through the scale heading the correct direction. There are marks for the location of your front axle and drive axle, and a speaker button very close to your driver’s window.
Push the speaker button that notifies the attendant you want to be weighed. They will ask, “Is this your first weigh?” and may ask, “Name of your rig?” Tell them the brand of your trailer.
The process of weighing takes about 15 seconds. The attendant will tell you to pull around.
Park your rig in the truck parking area and see the attendant inside for payment and your receipt.
Unhook your fifth wheel in the parking lot and pull your truck through the scale, repeating the process. This gives you the weight of your truck with a full tank of fuel.
Pay for your second weigh and hook your trailer back up.
The receipt gives you four lines of information:
Steer axle weight (truck front axle)
Drive axle weight (truck rear axle)
Trailer axle(s) weight
Total gross weight
The cost of your first weigh is usually between $10 and $15. A second weigh on the same day is usually half price.
Some owner and education rallies provide an individual wheel weigh, which can be very useful information to find out if your RV weight is balanced or overloaded on any individual wheel.
My Weight Information
Truck Weight Unhitched
Steer Axle - 4,960 lbs
Drive Axle - 3,920 lbs
Total Truck Weight - 8,880 lbs
Truck & Trailer Weight
Steer Axle - 5,420 lbs
Drive Axle - 8,500 lbs
Trailer Axles - 14,500 lbs
Total Combined Weight - 28,420 lbs
Now the hard facts:
The data reflects that I am well within limitations in most categories, but need to reduce about 1,000 lbs. of weight in the RV, preferably in the front section to reduce the pin weight. Just having this information helps our awareness when tempted to add new things, and gives us incentive to purge excess “stuff”.
I weigh the rig about once a year to make sure we are staying as close to limits as possible. We periodically reorganize and clean out storage, clothes and kitchen areas but we also tend to add things along the way. It all affects the overall weight, and those numbers are critical for safety and ensuring the longevity of our truck and home.