Does tongue weight affect MPG? (A 3point guide)

In this article, we will answer the following question: Does tongue weight affect MPG? We will explain what tongue weight is, how to measure and regulate it for a safe towing experience. 

Does tongue weight affect MPG?

Yes, tongue weight can affect both MPG and how easy your vehicle is to drive. An overloaded trailer can represent a 2% to 5%  fuel increase. 

  • If the tongue weight is light, the weight moves behind the axis; 
  • If the weight of the tongue is heavy, it moves in front of the axis, making it more difficult to manage the towing vehicle. 

This also affects the way your camper or caravan sways, stops and moves on the road.

What is tongue weight?

Tongue weight is the force applied by the tongue of the trailer to the hitch of the towing vehicle. 

The industry standard for tongue weight is between 9% and 14% of the total trailer weight (GTW). This weight allows you to control the trailer when coupled, which makes driving safer. When the tongue weight is incorrectly calculated, it affects the trailer and can cause accidents when towing.

For the more experienced RVer, the weight of the tongue is a lever. The trailer axle is the hub, and that’s where the lever rotates to be towed. This allows a trailer to turn and adapt to road conditions, speed and wind without moving back and forth all over the place. 

How to determine the tongue weight?

When you think about the tongue weight, you may not know what you are looking for, especially as a beginner RVer. The simplest way to determine if tongue weight is an issue is to step back from setup after setting up your hitch.

See the trailer itself and the towing vehicle. If either of them is leaning forward or backwards, your tongue weight is uneven and you will have problems when towing.

There are a few ways to figure out the right tongue weight for your RV setup. Depending on who you talk to, they swear by one method and take down another. It is important to find the right way to determine the tongue weight for you. It takes some practice to get the weight right, but it’s important that you take the time to learn how to calculate and adjust it.

Note: Remember that the correct tongue weight must be between 9% and 14% of the GTW, depending on the setting. Check with the manufacturer’s guidelines for your RV and towing vehicle for the correct weight.

The equation for calculating the weight of the tongue is simple:

GTW X Percent (manufacturer recommended) = Tongue Weight

Measurement and regulation of the tongue weight

As we said before, there are several ways to adjust the tongue weight. Once you have more experience with it, you will be able to do it by eye in most situations. For now, we recommend finding a more comfortable method for your setup.

  1. If you travel and check your tongue weight every time, you can make it easier by purchasing a tongue weight scale. Tongue scales are compact specialized devices that take the guesswork out of measurements. This is by far the best way to measure your tongue weight if you can’t get to a commercial weighing station.

Here’s how to measure your tongue weight with a tongue weight scale:

  1. Park the vehicle and trailer on a level surface.
  2. Slide the ladder under where the trailer tongue grip touches the ground.
  3. Pull the trailer jack in until it is pressed into the scale.
  4. Detach the trailer and view the numbers.

Most tongue weight scales can handle up to 2,000 pounds or about a 20,000-ton trailer. Be sure to read the capacity of the scale before purchasing and follow the instructions on how to use the scale related to the tow configuration.

2. Use a bathroom scale to calculate the tongue weight. If the trailer weight is smaller, such as 3,000 pounds or lighter, a bathroom scale can be used to measure the tongue weight. This method is a little more complex than a tongue weight scale, but it’s easy once you get the hang of it.

Note: You can use a bathroom scale to calculate your tongue weight, but it may not be as accurate as using a tongue weight scale or visiting a commercial weigh station. Keep this in mind if you get close to the weight limit.

Make sure your bathroom scale is up to the challenge of supporting the weight, otherwise you will have a broken scale and no reading. We recommend that you invest in a bathroom scale to measure the weight of your tongue relative to that of your bathroom.

You will need a bathroom scale, a brick, two pieces of pipes, and a 2 ‘x 4’ piece of wood that is four to five feet long.

Here are the steps to follow to use a bathroom scale to measure your tongue weight:

  1. Place the brick and scale three meters from each other and make sure they are the same height.
  2. Lay a pipe on long routes through the brick and ladder.
  3. Set yours 2 ‘x 4’ above the pipes.
  4. Place the tongue ball socket on top of the 2 ‘x 4’ two feet from the ladder and one foot from the brick. This will distribute the weight in a 3: 1 ratio on the scale.
  5. Make sure the socket is at the same height as the ball attachment. (You may need to use an extra piece of wood on the 2 ‘x 4’ for this.)
  6. Now get the reading on the bathroom scale and multiply it by three since the weight on the scale is at 3: 1 ratio and you have your tongue weight.

3. Use a commercial weight scale to find the tongue weight. This involves a few steps but is simpler than using a bathroom scale. Drive your trailer to a commercial ladder at a bus stop or material supply centre.

Here’s what to do at a commercial loading station to measure the weight of the tongue:

  1. Drive your vehicle on the scale only with the trailer loaded; make sure all four of your tires are on the scale.
  2. Take your weight measurement, and this is the X measurement.
  3. Detach the trailer from the vehicle while the vehicle remains on the scale.
  4. Take the measurement, and this is the Y measurement.
  5. Now subtract Y from X, this is your approximate tongue weight.

Play around with these different methods to find out which one suits you best. It takes some practice with each method to get it right. Once you find the most efficient way to measure the tongue weight for the towing setup, towing the trailer will be safer for you. Before you know it, you’ll be a tongue weight measuring machine!

The bottom line

Understanding the weight of the tongue is essential to staying safe when towing a vehicle, no matter where you are going or what you are towing. Trailer swaying is a fatal danger on the road. When the trailer is out of control, it will collide with other vehicles or take you off the road. In severe weather, this can be tragic. 

Please feel free to contact us should you have any questions or comments on the content!

FAQ on Does tongue weight affect MPG?

How to regulate RV gasoline consumption?

To regulate RV gasoline consumption: 

  • Avoid accelerating the accelerator. 
  • Avoid climbing too high in the towers.
  • Anticipate traffic. 
  • Stop the engine. 
  • Shift gears quickly. 
  • Shift down rather than brake. 
  • Avoid leaving the air conditioning always on.
  • Use cruise control.

What happens if you tow too much weight?

If you tow too much weight, the rear of the car will be pushed up and the front is pushed in. The result is that the grip deteriorates, the trailer becomes more unstable and the range of the low beam is shortened.

What is the tongue weight?

The tongue weight is the downward force that the trailer coupler exerts on the hitch ball. An unbalanced reed weight can cause kicking or loss of control. 

By loading your trailer 60% of the weight in the front you are placing 10-15% of the GTW on the hitch ball of the vehicle. For a minimal fee, you can weigh your trailer at a highway truck stop. Never exceed the maximum tongue weight of your truck.


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