Can your truck, SUV, or other vehicle handle that towable RV you’re about to buy? The answer depends on how heavy the trailer is, how much of that weight is distributed to your tow vehicle’s hitch, how many passengers you plan to carry inside of the tow vehicle, and a few other items covered in this post about RV towing weights.
Vehicle Tow Rating
Your vehicle’s manual will include a Tow Rating that is the maximum amount of weight that can be towed, or “pulled.” This is the specification that is often referenced in television commercials and by your local auto dealer. However, this maximum tow rating often represents an unrealistic scenario of trailer weight distribution and tow vehicle usage.
Here’s a great example: the famous towing of the space shuttle Endeavor by a 1/2 ton pickup, the Toyota Tundra. See all those wheels under Endeavor’s nose? They are bearing the weight of the space shuttle, not the Tundra’s trailer hitch.
This photo really proves the point. The space shuttle’s weight rests completely on a set of independent trailer axles whereas the arm connecting that trailer to the tow vehicle, also called the trailer tongue, isn’t transfering any of the Endeavor’s weight to the truck. Even though the space shuttle far exceeds the Tundra’s 10,000 pound tow rating, it can pull this amount of weight, at least temporarily for a media stunt, because hardly any weight is being placed downward on the truck’s frame, wheels, tires, etc.
This photo shows a more realistic example of a similar Toyota Tundra pulling a small trailer that transfers between 10-20% of its weight to the truck via the trailer tongue and hitch. Unlike the space shuttle Endeavor, an RV typically features axles toward the back of the trailer and not in the front. As such, all of the trailer’s front weight is transferred to the tow vehicle. Additionally, most RV’errs are not pulling their trailer down flat roads like when the Tundra paraded the Endeavor through the streets of Los Angeles. Most RV’ers are wanting to take their trailer up and over mountain passes to some amazingly beautiful campgrounds.
So, What’s the Solution?
With all this in mind, let’s take a look at some real-world scenarios and how anyone can use some fairly simple math to determine how heavy of an RV trailer can be safely towed by a tow vehicle while also looking at an easy way to verify that those weights are within safe limits.
Tow Vehicle Payload Capacity
All vehicles feature a Gross Vehicle Weight Rating (GVWR) rating. This is the maximum amount of weight that the vehicle can support on the frame, wheels, tires, and other critical load-bearing structural portions. This rating includes the vehicle itself, which oftentimes referred to as a vehicle’s “curb weight.”
Here’s a sample Toyota Tundra with a GVWR rating of 7,200.
You can then look in the user manual to obtain the truck’s base curb weight, which is the weight of that base model vehicle when it left the factory, plus a full tank of gas also accounted for. The Toyota Tundra used for this example has a curb weight of 5,650 pounds.
There will sometimes be an additional sticker located in the driver’s door jam that indicates the weight of all optional equipment that was added by the factory. This is important because the user manual specifications will assume a base model without any optional components, and I don’t know anyone who drives a base model. In the example Tundra, there are a few optional features such as a truck bed liner and skid plates that were added at the factory. As such, the curb weight is increased by 60 lbs to a total of 5,710 lbs.
Finally, we have to account for any dealer or owner added aftermarket equipment plus any permanent cargo always carried inside the vehicle. For the example Tundra, this totals an estimated 160 lbs after considering a fiberglass truck topper with a pre-installed roof rack, a child car seat, and a few accessories like jumper cables and a tow strap stored under the back seat.
A little math calculates the resulting payload capacity for this example Toyota Tundra:
GVWR: 7,200 lbs
(door jam sticker and owner’s manual)
Base Curb Weight: 5,650 lbs
(owner’s manual for specific base model)
Factory Added Equipment: 60 lbs
(yellow door jam sticker)
Owner Added Equipment & Permanent Cargo: 160 lbs
(estimate for fiberglass truck topper w/ roof rack, child car seat, and jumper cables)
ESTIMATED VEHICLE WEIGHT: 5,650 + 60 + 160 = 5,870 lbs
ESTIMATED PAYLOAD CAPACITY 7,200 – 5,870 = 1,330 lbs
1,330 lbs of payload capacity may seem like a lot. An RV dealer might even claim that someone can still tow that 10,000-pound travel trailer since only 10% of the weight is typically transfered to the tow vehicle’s hitch. But that tow vehicle isn’t just supporting the trailer – it’s also hauling the driver, some passengers, and everyone’s cargo.
Let’s look at a family of four where dad weighs 200 lbs, mom is at 130 lbs, and two kids plus a dog adds another 170 lbs, for a total of 500 lbs in occupant weight – just for an easy but fairly realistic number. Each person will likely bring a duffel bag of clothes and other personal items plus some firewood, a cooler, and a box of dry food for the camping trip – let’s call this another 150 pounds. This all adds 650 lbs to the weight of our sample Toyota Tundra for a revised payload capacity of:
ESTIMATED REMAINING PAYLOAD CAPACITY: 7,200 lbs GVWR – 5,870 lbs truck weight – 650 lbs occupants/cargo = 680 lbs
680 pounds is the maximum amount of hitch weight that a camper should place on this example Toyota Tundra. Other tow vehicles may not have a truck topper but may instead be an SUV with a heavier curb weight and thus a lower payload capacity to start with. Others kids may be older and weigh more, or that family might bring four bikes in the bed of their truck, with each bike weighing 35 pounds or more. Either way, the weight of each passenger and total cargo must be accounted for and deducted from the vehicle’s payload capacity to obtain the correct maximum trailer hitch weight.
Maximum Trailer Weights
RV manufacturer will typically list at least three important specifications for camper trailers.
First is Gross Vehicle Weight Rating (GVWR). This is the same concept as with the tow vehicle, but is the maximum weight that the trailer can hold. This number should never be overloaded or else the trailer axles, frame, or tow vehicle could suffer a catastrophic failure. As crazy as it sounds, there are plenty of RV trailers that will exceed their GVWR by simply filling both their fresh, grey, and black water tanks up with water. These units are built for towing a mostly empty trailer to a full hookups campground. The trailer’s GVWR should also be at or below the tow vehicle’s “maximum tow rating” (how much it can “pull”) while still considering the impacts to the tow vehicle’s payload capacity (discussed again below).
Another common specification is Dry Weight. This number indicates how much the camper weighed when it rolled off the factory floor. As with the tow vehicle’s curb weight, each camper might have optional equipment added at the factory, so there is an updated sticker affixed to the trailer that should be used instead of the website or brochure specifications. It is very important to consider is that this measurement does not include necessary items like propane, batteries, water, and personal cargo.
With the above two numbers, either the manufacturer or anyone else can calculate the Cargo Carrying Capacity (CCC), which is the GVWR minus Dry Weight. This number indicates how much cargo can be safely carried inside of the camper before exceeding the GVWR rating. Even relatively smaller figures like 500 pounds may sound like plenty until considering the weight of a typical RV battery (55 pounds), 20-pound LP tank (which is actually 37 pounds for the tank and 30 pounds of propane), and the water tanks. For example, a dual battery, dual propane RV with a full 35-gallon water tank would already be over a 500 pound CCC even before adding in cookware, clothing, and other personal cargo.
Camper Tongue/Hitch Weight
The Dry Hitch Weight is often quoted by an RV manufacturer or dealer. But this is not how much weight will be transferred to a tow vehicle under typical use. Instead, this is the hitch weight of the trailer before adding heavy items like propane, batteries, water, and other personal cargo – all of which often rides toward the front of the trailer if not on the trailer tongue itself, like LP and batteries.
Calculating the estimated hitch weight with actual camper cargo loaded is a bit of an art. But this can be estimated before even purchasing a camper by noting the weight of each primary cargo item and then calculating how much of that weight will be transferred to the hitch versus the camper axle. If, for example, there is one 20-pound propane tank that weighs 37-pounds when full and it is 3 feet from the very front of the trailer (where hitched to the vehicle) and 6 feet from the trailer’s axle, the resulting tongue weight for this item is 24.66 pounds, calculated as 37 pounds * (6/9). The number 6 represents how close that item is to the trailer axle while the number 9 is the total length between trailer tongue and axle.
Keep in mind that while some items like water tanks, LP, batteries, and food inside of a fridge are mounted in fixed positions, other personal cargo like cookware, clothing, tools, and dry food may be positioned in different locations to optimize hitch weight. Putting something toward the back of the trailer, behind the axle, can actually take some weight off the trailer tongue, just like sitting on a playground see-saw.
Always remember that tongue weight should be between 10%-20% of the total trailer. Anything less will likely result in significant trailer sway.
Here are the calculations I came up with before purchasing our first RV trailer, a Flagstaff MAC 228 popup:
Dry Hitch Weight: 331lbs
(factory weight w/o propane, battery, etc)
Propane Tanks: 37 LBS * 2 tanks (6/9) = 49.3 lbs
(two 20# propane bottles mounted 6′ from trailer axle, 3′ from trailer tongue)
Battery: 55 lbs * 2 batteries * (5.5/9) = 67.2 lbs
(two 55 lb deep cycle batteres mounted 6.5′ from trailer axle, 3.5′ from trailer tongue)
Fresh Water Tank: 20 gallons * 8.34 lbs/gallon * (3.5/9) = 64.9 lbs
(20 gallons of water mounted 3.5′ from trailer axle, 5.5′ from trailer tongue)
TOTAL: 512.4 lbs (331 + 49.3 + 67.2 + 64.9)
Even this lightweight popup camper was barely within the leftover payload capacity for my Toyota Tundra after accounting for my family, our bikes or kayaks, and some other personal cargo.
These are just a few simple examples. Each scenario should account for every item planned for a particular configuration, including the available storage locations within the trailer.
Some owners, and even some vehicle or RV dealers, think that a Tow Package or Towing Mode button changes all of the above. This optional package may help with the vehicle’s tow rating, allowing it to pull more weight thanks to an add-on transmission cooler or modified gear ratio transmission, but it generally doesn’t do anything for the payload capacity measurement.
One small exception is the Ford F-150 truck, model years 2015 and forward. Thanks to aluminum body construction, the curb weight of this vehicle has been reduced, thus increasing payload capacity over most steel-bodied peers. Several F-150 trucks have a payload capacity of 1,800 lbs or higher. A “Heavy Duty Payload Package” (not to be confused with tow packages) further increases this number through the use of a thicker vehicle frame, heavier duty wheels, and other options that when combined together at the factory, increase the truck’s GVWR and resulting payload capacity (as high as 2,600 lbs as of 2018).
I validate my estimates with a scale, which is commonly found at truck stops, a local municipality’s trash dump, or a gravel pit. Weights that I minimally record include:
- Tow vehicle (both axles) with camper cargo fully loaded and hitched to vehicle, plus all occupants/cargo inside vehicle
- Tow vehicle (both axles), same as above but without camper hitched
- Camper (axle only) fully loaded with cargo
#1 is never abovey tow vehicle’s GVWR rating.
To ensure my camper isn’t past its GVWR requires a bit of math, namely:
- Camper Hitch Weight: calculated as #1 minus #2 (or directly w/ a Sherline Tongue Weight scale)
- Camper Total Weight: calculated as #3 (camper axle) + Camper Hitch Weight (calculated in prior bullet)
Shouldn’t My Dealer Know All This?
Most dealer salespeople don’t understand or don’t want to understand these important weight concepts. They are paid to sell campers, and complications don’t generally help sales.
There are some dealers out there that not only understand this concept but explain it to their customers and help calculate everything before doing a final weigh-in just prior to purchase. I recommend buying from these dealers. Roberts Sales in Denver, Colorado is one such example who loaded up my first popup camper with water, batteries, and propane to take an actual hitch measurement before I purchased.
What if I Overload?
Plenty of drivers I see are overloaded. Some incorrectly think that a Weight Distribution Hitch, upgraded shocks, or rear shock airbags solve the problem. Many don’t even realize the problem because they’ve heard that their truck “can tow 10,000 pounds.”
So what happens if someone overloads a tow vehicle or camper trailer?
- If they’re in an accident, they may be assigned blame regardless of the other circumstances just because they were overloaded and in violation of state law. Their insurance might try to disclaim responsibility. Both are a liability concern.
- Their tires may blow out or their wheels may fall off. This is an inconvenience at rest but is a potentially life-threatening accident on the road.
- Their brakes might not stop quick enough, if at all.
- Their vehicle pr trailer components will likely wear down and fail prematurely. Springs, shocks, tires, and brakes will all start to result in an unpleasant ride both with and without the camper in tow. Their engine and transmission might even wear out from the excess stress.
It is in an RV owner’s best interests, both safety wise and financially, to stay within the proper towing guidelines of their vehicle and camper.
All of the above is provided for entertainment purposes, may include mathematical errors and other ommissions, may be based on out of date and now inaccurate information, and should NOT be taken as professional engineering or legal advice.