What is Tongue Weight? Understanding Hitch Weight & How It Impacts Towing

This in-depth guide explains ‘what is tongue weight?’ Plus, the importance of hitch weight and how it impacts towing capacity. Our goal is to deliver all the details you need to have lots of fun on your next adventure!

If you are headed for the lake or a river to go boating, chances are, depending on the size of the boat, you will haul it on a trailer behind your truck. That means you will need to put a hauling ball, also known as a hitch, on the back of the vehicle. This allows you to connect it with the tongue extension on the front of the trailer.


Hitch ball on backend of truck

what is tongue weight

Trailer tongue

what is hitch weight

But wait. It is not as simple as that. There are some things you need to know first to set up everything properly for hauling. If you only have a car, you will be limited to the amount of weight you can haul, based on the car’s manufacturer’s warranties and documentation. In the case of kayaks, you can easily mount these on top of the car on racks. Vault Cargo has excellent options for doing just that. Check out our innovative Universal Folding Kayak Rack—meant to fit on just about any vehicle.

Gross Combination Weight Rating (GCWR) and Gross Trailer Weight (GTW)

If you are planning to use a pickup truck, check your towing vehicle’s documentation to see how much you can safely tow. Add up the vehicle weight, how many people will be in the vehicle, and the weight of the trailer. Plus, what will be parked on the trailer, such as a motor boat, or several canoes, camping gear, or a small trailer home in lieu of a boat trailer.

Related: What is a Hitch Rating

While you may have good documentation on your towing vehicle, you might not have much idea about the weight of a trailer with a medium-sized motor boat. The best way to get this weight is to have someone haul your boat and trailer to a Department of Transportation (DOT) truck scale location. Get the trailer and boat over the scale, disconnect from the tow vehicle, and get the weight. From this measure of the weight, you will get your gross trailer weight (GTW). You can also do this for your vehicle too, separate from the trailer. Just to be sure you have the weight correct. With both measures combined, you now have your GCWR. Just add in any body weights (amount of people), and what cargo you will have in the truck with you.

What is Tongue Weight?

Before you go out and buy just any hitch ball, you must first recalculate the full weight of the trailer with boat, camper, or whatever you are hauling behind you. The tongue weight will be roughly 10% of your fully loaded trailer (with boat). So, if you had a 5,000-pound (trailer and boat) behind you, the tongue weight will be 500 pounds. This is the amount that will press down on your hitch and ball that is installed on your towing vehicle. You may need a 2” ball.

If you do not have the right class of hitch and ball installed now, you can go over to an automotive parts place to get what you need. Measure the cap that goes over the ball first so you know what size you have on the trailer. Take a ruler and measure across the bottom opening. Then stick the ruler up into the cap to get its depth. You might need a very narrow ruler to do this to get to the top of the inside of the cap.

Hitch Class

Check online first to see what places have what you need. Then call ahead before you go, to save yourself from the aggravation of the store not having what you need in stock. You may need a whole towing package which includes:

  • The hitch adapter
  • A hitch extender (you don’t want the trailer too close to your truck)
  • The trailer ball, which comes in three sizes (1-7/8”, 2”, 2-5/16”)
  • And the hitch pin that locks the ball mount into the hitch tube. That is if you do not have anything installed yet.
  • The kit may also include a trailer tongue which you would remove the old one off the trailer and put on the new one, if you need to.
  • You will need the wiring kit for trailer lights and trailer turn signals. These must always be working properly on the road.
  • Add chains for more a more secure hookup.

What Happens with Improper Weight Distribution?

If your trailer’s tongue weight is too light while sitting on the hitch ball, the trailer will weave or sway. This can make any towing situation very hazardous. Too much weaving and you will have an accident, if not you, maybe for someone coming up behind you on the road. The second scenario is if the trailer tongue weight is too heavy, then the towing car or truck you are driving, may have trouble steering properly on the road. You need to be in full control of your vehicle to avoid accidents.

Visual Inspection

Visually, you can see either problem in plain sight after a hookup. If the trailer tongue is too light, you will see the connection between the trailer and the vehicle hitch bowing upwards. The cap over the ball will not be properly aligned horizontally. What you can do to solve this problem is to move weight from the back of the trailer to the front of the trailer. If you are hauling a boat, you may need to shove it forward onto the trailer until the connection is horizontal. The overall connections of both sides should be horizontal in appearance.

If the trailer tongue connection to the hitch is too heavy, you will see the connection bowing downwards, and the front of the towing vehicle may look like the front wheels barely have any vehicle weight on them, while the back wheels are compressing under the wheel wells. In this case, move the boat back farther on the trailer to take the pressure off the back end of the towing vehicle. That should fix your problem so you can go have fun!