Before you purchase an RV, you need to find out what your RV towing capacity is! Not only is it dangerous to pull an RV that exceeds your vehicle's maximum towing capacity, but it can put a lot of wear and tear on you vehicle too. Let's determine how large of an RV your vehicle can handle.
Your towing capacity, also sometimes referred to as payload, is how much weight a vehicle can support aside from passengers and cargo. To calculate this, let's gather some numbers off the stickers on the vehicle. Look in the door jam for a sticker that shows the vehicle's GVWR, or Gross Vehicle Weight Rating. This is the total amount of weight that can be put on the vehicle, including its own weight. This includes passengers, cargo, and the weight of an RV. Let's find out how much everything but the trailer weighs to determine what’s left for towing. Load all of your camping supplies and passengers into the truck and get it weighed at a weigh station or truck stop. Subtract this amount from the GVWR and you get the amount left for a trailer. As an example we used a 2016 GMC Sierra 3500 with a GVWR of 10,700 lbs. Our loaded weight was 7,363 lbs. We subtracted this from the GVWR to get a 3,337 lbs. towing capacity.
If you are unable to find your GVWR or get your vehicle weighed, look for a sticker that reads “Occupant and cargo weight may not exceed ...” followed by a weight. This is your Occupant and Cargo Carrying Capacity (OCCC). This is what is left after the weight of the vehicle alone. Now you just need to weigh all the cargo and occupants separately. When we weighed everything separately we got 384 lbs. We subtracted that from the OCCC rating, which is 3,721 lbs. on our GMC, and again we get 3,337 lbs.
Now we need to take a look at the engine in the GMC and see how much it can pull. This is called the Gross Combined Weight Rating which is how much weight an engine can pull, including the tow vehicle and the trailer. Our GCWR is 21,100 lbs. (we'll save this number for later). Now we just need to take a look at the trailers!
There are a lot of different weights and measurements listed on an RV. There’s shipping weight or dry weight, GVWR, hitch weight, and much more. The number we want to work with again here is the GVWR to figure out how much weight the trailer is going to put on the hitch. You'd assume that hitch weight would be the correct amount, but unfortunately it's not that easy. Since travel trailers and fifth wheels put a different percentage of their weight on a vehicle, the calculations vary slightly.
Travel Trailer Tongue Weight
A travel trailer transfers about 15 percent of its GVWR onto the ball of the hitch. This weight is called tongue weight. To calculate this, simply multiply the GVWR by .15 and you will get the amount of weight it will put on the vehicle. Let's look at a Catalina travel trailer with a GVWR of 10,900 lbs. as an example. If we multiply 10,900 by .15, we get a tongue weight of 1,635 lbs.
Fifth Wheel Pin Weight
A 5th wheel rests a little more of its weight on a hitch than a travel trailer does at about 25 percent. These RVs rest on a king pin hitch and this weight is called pin weight. We’ll use another Catalina that has a GVWR of 17,000 lbs. If we multiply this by .25, we get a pin weight of 4,250 lbs.
Our suspension is well within range of our payload, but let's see if the engine can handle it. What we need to do is add the GVWR of the GMC to the GVWR of the trailers and make sure it comes out under the GCWR.
10,900 + 10,700 = 21,600 lbs.
17,000 + 10,700 = 27,700 lbs.
While our suspension can handle the weight of the trailer, it doesn’t look like our engine can! So what can we tow? We can calculate max weight for both the suspension as well as the engine and then use the lower number so we ensure that our vehicle can handle the RV.
Max Trailer Weight
After finding that we can’t pull the Catalinas, we want to find out how much weight we can pull. Again, the math here is pretty simple. Take the payload of the vehicle and divide it by the percentage of the trailer that will be put on the hitch. So we’re going to divide the 10,900 by 15 percent for the travel trailer weight and by 25 percent for the 5th wheel weight. When we do this we find that we can handle a travel trailer up to 72,666 lbs. and a 5th wheel up to 43,600 lbs. Then we want to subtract the GVWR of the truck from the GCWR and see how much weight is left that the engine can handle. This gives us 10,400 lbs. which is WAY lower than what our suspension can handle.
Now you have the tools to figure out what your vehicle can tow and you can use it to find the right-sized trailer. When shopping in person, look for information stickers near RV doors, and when shopping online, refer to the Specs section on the product page.