In the RV industry, we hear this question a lot: "Will my vehicle be able to pull it?” This is a great question and one that should be addressed during the RV buying process to ensure that you don't end up purchasing an RV that is too heavy for your tow vehicle. Overloading a tow vehicle can be dangerous! If your RV is too heavy for your vehicle, you will most likely end up with transmission and suspension problems and your tires will wear down very fast. In addition to ruining your vehicle, you'll also be putting yourself and those on the road around you in peril if you're not equipped to pull such a heavy load. So let's avoid all of this unnecessary stuff by calculating what your vehicle can safely tow.
Because there are a lot of weights listed on RVs, it can be difficult to determine exactly how much an RV weighs. Most of an RV's weight is going to be carried on its own axles, so it’s only going to transfer a portion of its weight onto the vehicle. In order to find out how much, you need to calculate tongue weight for travel trailers and pin weight for fifth wheels.
Tongue weight is the amount of weight the trailer is putting on the hitch ball. A travel trailer will generally put around 15 percent of its weight on the ball. To calculate tongue weight, you first need the Gross Vehicle Weight Rating (GVWR). It’s important that you use this number. This is the amount the trailer would weigh if you put the max allowable amount of cargo in it. You want to use this number so that you don’t have to worry about the weight of the cargo you put in it. All you have to do is multiply the GVWR by the 15 percent and you will have the amount of weight it’s going to put on the hitch.
A fifth wheel rests on a king pin, hence the term pin weight. Fifth wheels tend to rest a little more weight on a vehicle. It is around 25 percent of their GVWR. The same calculation will yield the weight on the pin. Simply multiply the GVWR by 25 percent and you will get the amount of weight that will be put on the pin.
Now that you know how to figure out how much weight the RV will transfer to your tow vehicle, you want to find out if your vehicle can handle it. This is going to be called towing capacity, or payload.
The payload of a vehicle is the amount of weight it can handle on the chassis aside from itself, occupants, and any cargo in the vehicle. We need to start with GVWR here too but from the vehicle itself. Check your vehicle's door jams and you should be able to find this number on a sticker. Now that you have your GVWR, you need to find out how much the vehicle weights, as well as the people and stuff you plan to have in it. The easiest way to do this is load everyone and everything up and head to a weigh station or truck stop to have it weighed. If this isn't doable, you need to research your vehicle’s curb weight. Curb weight is how much your vehicle weighs with all fluids included, but without any passengers or cargo. Then you simply weigh your passengers and cargo separately and add it to the curb weight. Once you have the weight of the vehicle along with all the passengers and cargo, you subtract that number from the GVWR. This gives you the amount of weight you have left to tow.
If you are unable to find your vehicle’s GVWR or can’t look up the Curb Weight, there is an alternative way to figure it out. There will be a Tire and Loading sticker on the vehicle that will tell you the max allowable weight of cargo and occupants. This is basically GVWR with the weight of the vehicle already taken out. It is called the Occupant and Cargo Carrying Capacity (OCCC). So now you just need to weigh passengers and cargo and subtract from this number.
Now that you have determined how much weight you have left to tow, you just need to be sure that your trailer percentage stays within that. If you don’t have a specific trailer picked out and you just want to know how much weight you can pull, there’s a simple equation you can use. All you have to do is divide the payload by the percentage of weight to be put on the vehicle and you have the total weight it can handle. Let’s look at an example so you can see exactly how this works.
These calculations are all about the suspension, so you need to also keep in mind what the engine can handle. Now you want to look for Gross Combined Weight Rating (GCWR), which is the total weight the engine can handle between the trailer and the vehicle itself. To calculate this, just add together your GVWR of the trailer with the GVWR of the tow vehicle and make sure it’s under the GCWR.
We want to look at both a fifth wheel and a travel trailer to see how this math is going to work. Get ready to dust off your old algebra skills and show your kids how solving for X really does come in handy!
The truck we’re working with is a 2016 GMC Sierra 2500. The fifth wheel we like is a Salem and the travel trailer is Sunset Trail Reserve. Here are the weights we have based on using the truck's GVWR and having it weighed:
Sunset GVWR: 10,408 lbs.
Salem GVWR: 10,072 lbs.
Truck GVWR: 9,300 lbs.
GCWR: 21,100 lbs.
Scale Weight: 6,265 lbs.
First let’s figure out how much of the trailer weight is going to be put on the truck.
Tongue & Pin Weights
We need to multiply the trailer GVWR by the percentage of the weight it’s going to transfer onto the truck.
Sunset: 10,408 * .15 = 1,561 lbs. tongue weight
Salem: 10,072 * .25 = 2,518 lbs. pin weight
Next we need to know what our payload is to see if we can handle these trailers.
Payload Using GVWR and Scale Weight
We will subtract the weight from the scale from the GVWR of the truck.
9,300 – 6,265 = 3,035 lbs. max payload
Using these calculations, we can see that this truck will easily pull either of these trailers. Now let's see if we get the same number using the OCCC method.
Payload Using OCCC and Individual Weights
This is going to take a little more time since you have to weigh everyone and everything separately, but you should be able to get the same number as the previous example using this method, or at least very close.
OCCC: 3,559 lbs.
Driver: 203 lbs.
Passenger 1: 181 lbs.
Passenger 2: 110 lbs.
Cargo: 30 lbs.
We will subtract our passenger and cargo total from the OCCC:
3,559 – (203 + 181 + 110 + 30) = 3,035 lbs. max payload
Either way we calculate it, we’re able to tow either trailer on the chassis. This doesn’t always mean the engine can pull it though, so we need to check that next. Let's add the GVWR of the vehicle and trailer together and see if it’s under the GCWR.
10,408 + 9,300 = 19,708 lbs.
10,072 + 9,300 = 19,372 lbs.
Since our GCWR is 21,100, our engine can also handle either RV.
Max Trailer Weight
Now, if we decide we don’t actually like either of these RVs and want to keep shopping around, we can simplify this process. All we have to do is calculate the total trailer weight our truck can handle. Remember that we said we simply divide the payload by the percentage of the trailer weight that will be put on the hitch.
3,035/.15 = 20,233 lbs. max travel trailer weight
3,035/.25 = 12,140 lbs. max fifth wheel weight
Then let’s see the max weight the engine can handle by subtracting the GVWR of the tow vehicle from the GCWR to see what GVWR of trailer we can handle:
21,100 – 9,300 = 11,800 lbs. GVWR
As you can see, the weight our engine can handle is lower than the weight our suspension can handle, so we need to use the lower number of 11,800 lbs.
Now you’re ready to start shopping based on how much weight your truck can pull. When you’re shopping for RVs, you can find the weights you need in the specs online and also on a sticker near the door. If you’re checking out our website, you can filter your search by the amount of weight your truck can pull! Give us a call at 1.877.616.4528 with any questions and we’ll connect you with a specialist that can help you out!