When driving a car, most of us rarely give much thought to how much it weighs. But when driving a full-size RV, knowing how much you weigh can literally mean the difference between life and death!
FYI: This is a somewhat technical post on RV weight and safety. If you’re an RVer, this is information you really need to know. If you just want to read about our travel destinations and adventures, we’ll have a new post up for you soon. Either way, we hope you’ll enjoy this short video!
Every RV comes with a plaque that lists the maximum safe weight for the vehicle when fully loaded. In our case, the maximum is 22,000 pounds, or 11 tons! That’s a lot of weight. It also lists the maximum weight on each axle, and the maximum if you are towing another vehicle.
Driving overweight can cause a list of catastrophic problems with your vehicle:
- The suspension/shock absorbers can fail, causing you to (best case) bottom out when hitting bumps in the road, or even (worst case) lose a wheel while driving at highway speeds.
- The brakes can fail by becoming overheated while trying to stop more weight than they can handle.
- The transmission can fail.
- The tires can fail, causing a blowout at highway speeds.
And if your own vehicle doesn’t fail, what about that bridge you’re crossing with a six-ton weight limit?
So, the first thing any RV owner should know is how much your unit weighs with everything you usually carry in it – because everything counts! For instance, our motorhome has a 100-gallon fresh-water tank. Water weighs 8.34 pounds per gallon, so when we have a full tank, we are carrying an extra 834 pounds in water alone! Gasoline is 6.3 pounds per gallon, so if our 75-gallon tank is full, that’s another 472.5 pounds. Now, add three dogs and a cat, two people, all of our clothing, food, tools, pots and pans, camping equipment, games, books, computers and electronics, bicycles and heavy-duty rack, and you can see how it all adds up very quickly.
That’s why we made a detour during our trip to have our RV weighed at the Escapees “SmartWeigh” station at the Sumter Oaks RV park in Bushnell, Florida. The advantage of SmartWeigh over the scales in most truck stops is that it weighs every wheel, not just every axle, which can help you redistribute the weight in your vehicle as evenly as possible.
GOOD NEWS! We passed. And we learned something new about our tires!
Fully loaded, our rig weighed 21,200 pounds, leaving us 800 pounds to spare even when our three grown kids are traveling with us!
Our front axle balanced out perfectly with 3,200 pounds on each wheel. The rear axle was close with 7,200 pounds on the right and 7,600 pounds on the left.
So, what does this have to do with tires?
I learned to inflate my car’s tires to the maximum pressure listed on the tire itself. But this is absolutely wrong! Each of the tires should be inflated according to the weight that its axle is supporting.
On a car, the weight is low enough that you can usually just inflate the tires to the pressure listed on the sticker on your door (or in some cases, inside the gas door). On a heaver vehicle like a motorhome you should look to the chart that most tire manufactures post on their website, based on the weight each axle is carrying. This inflation based on weight will assure that your tires have just the right amount of tread in contact with the road for maximum life, drivability, and stopping power. In our case, this means that our four rear tires should each be inflated to 80 pounds when cold. The front tires need 95 pounds.
Always fill your tires when cold! The heat of driving down the road causes the air to expand and can increase the internal pressure by as much as 15 pounds. The tire manufacturers take this into account on their recommend inflation charts.
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