5 Tips to Make Sense of Trailer Tow Capacities

Figuring out how much your car can tow or what car you need to buy to tow a camper can feel daunting. I am not an expert on this so I highly recommend you do your own research. I’ve pasted a couple of links below for resources I found helpful. Here are 5 few tips that helped me to figure out what I was comfortable towing.

1. Know your terms

There are a lot of acronyms when it comes to figuring out towing information. Keep a list handy until you get familiar with them. Here are they key ones that I used while trying to figure out my car’s true tow capacity:

1. Gross Vehicle Weight Rating (GVWR) is the maximum loaded weight of your that vehicle or trailer can take. This is the key (in my opinion) number to know because most RV manufacturers list this in their RV specs. This is the number I use in my trailer guide. This number relates to the trailer itself or the car itself but not both together. There is a lot of confusing and contradictory information about this online.

2. Dry weight is the weight of the trailer when it ships from the factory with no added gear, water, or food

3. Carrying Capacity or Cargo Capacity is the total amount of gear, water, and food that your trailer can carry.

4. Tonge weight is the amount of weight the tongue will put on the hitch attached to your tow vehicle

Often, an RV manufacturer will list the GVWR for the trailer, great, you know the maximum weight the trailer can carry. Some manufacturers list the dry weight and the carrying capacity or cargo capacity. In that case, you have to add those 2 numbers together to get an approximation of the GVWR for the trailer.

Here are a few more terms that you might come across

1. Payload is the weight of all of the gear, passengers plus the tongue weight of the trailer. It does NOT include the weight of your vehicle.

2. Gross vehicle weight is the total weight of the car, passengers, gear, and fuel plus the tongue weight of an attached trailer.

3. Curb weight is the weight of the vehicle without any payload or passengers. It is gross vehicle weight minus payload.

4. Combined gross vehicle weight is the total weight the manufacture has determined the vehicle can handle. This includes the vehicle, all passengers, cargo, and fuel plus attached trailers.

5. Max trailer weight is the most amount of weight that a vehicle can tow.

6. Max tongue weight is the maximum amount of weight that can be put on the hitch and is included in the max payload. This may vary depending on the type of hitch being used. As an example, it might be 500 pounds for a weight bearing hitch and 1200 pounds for a weight distributing hitch.

7. Dry weight is how much the camper weights without adding any water, gas or gear.

8. Max trailer payload is the maximum amount of gear, water and gas that can be safely carried in the trailer. The dry weight plus the max trailer payload is the trailers gross vehicle weight.

9. Trailer Gross vehicle weight is the total weight of the trailer with all contents.

2. Be cautious about what you read on the internet.

The information about how to calculate tow capacity is very confusing. I personally don’t agree with all the people that say you have to include the passengers and payload of your tow vehicle. I read my car’s manual and they don’t define it that way. Check your vehicle manual to understand terms.

I have a Subaru Outback XT with a tow capacity of 3500 lbs. If I search for “what camper can a Subaru Outback XT tow” I find articles that say I can tow an Airstream Basecamp! I would not tow any of the Airstream trailers with the Subaru Outback XT. The lightest Airstream Basecamp, the 16, has a dry weight of 3000 lbs. Dry weight, or factory weight, is the weight of the trailer without anything in it. Because I live on the West coast and go over mountain passes, I follow the 80% rule where I assume that my final, fully loaded, trailer should weight no more than 80% of my tow capacity. That means I can tow a trailer that weights 2,800 lbs fully packed with gear, food and water. The Basecamp is already above that without anything in it! Do your research and know your tow vehicle’s limits, don’t trust anyone else to know for you.

3. Know your tow vehicle and set your own boundaries

You have to set your own limits on what you will tow based on your comfort level and what you know about your tow vehicle. We tend towards cautious so the 80% rule we are following might not be right for you. Further, your tow vehicle might have a different set of packages that allows you to feel comfortable towing closer to the tow limit. My brother tows an R-Pod with a Jeep that has a 3500 lb tow capacity. The R-Pod has several versions that are 3,000 lbs dry weight and if you load it carefully can be at 3500 lbs. With the Jeep he has no problems, but that car is configured differently than our Subaru and so we considered our boundaries differently.

4. Water weights a lot!

You can get a small trailer with no water tanks (the Armadillo brand is a good example, see this post) but most have at least fresh water and grey tanks and many have fresh, grey and black tanks. Water weighs 8.34 lbs per gallon. If we continue with the Airstream Basecamp 16 example, that model has a 21 gallon fresh water tank so if you fill up the tank with water before you leave, you will have 175 lbs of weight just from water. It has a 24 lb combo grey/black tank so if you travel home with that full, you will have 200 lbs of water alone. If you travel with both full (which is unlikely) you would have 375 lbs of water which is 75% of the total carrying capacity for that trailer.

5. Watch for a low carrying capacity

Occasionally, you will see a trailer that seems to have everything you want in a very small size and low GVWR. In this case, check the carrying capacity! I’ve seen several trailers with lots of amenities but carrying capacities of 500 lbs. Not to pick on the Airstream Basecamp, but that one has a carrying capacity of 500 lbs. If you are going to travel with any of your water tanks full, you have to immediately deduct that from your carrying capacity. As it happens, we recently sold our pop-up camper and bought a new trailer and everything that was in our pop-up is was in our garage so I weighed it all, it was ~365lbs without clothes or personal items. Look for a future post for more about what our stuff weighs!

Assume you are heading out for the weekend with your Basecamp 16. You are boondocking so you load the camper with 21 gallons of water (175 lbs). Then you add 2 propane tanks (40 lbs), 3 days worth of food (~50 lbs I have not actually weighed that yet, stay tuned!), and all the stuff from our camper (365 lbs). Add that up and you have 630 lbs. More than your trailer carrying capacity. So if you love a trailer with a low carrying capacity be prepared to make some trade offs or be able to put a lot of your stuff in your tow vehicle.

Here are a couple of resources that I found helpful

What Camper Can my Vehicle Tow? A Safe Towing Guide