What Is Tongue Weight & How To Measure It
By Marshall Wendler
Last Updated: September 6, 2022
Tongue weight is an often overlooked and misunderstood travel trailer measurement, and there can be severe consequences if it isn't paid attention to.
There is more to towing a travel trailer than hitching up and heading out. You need to load the rig correctly, so it is appropriately balanced while going down the road; otherwise, the handling can be compromised and may lead to an accident.
On this page, you will learn how to measure tongue weight and find out what an acceptable trailer tongue weight is to safely tow your recreational vehicle down the road as you head out on your next grand adventure.
What Is Tongue Weight?
Let's start by first answering the question, "What is the tongue of a trailer?"
A trailer tongue is the part of the trailer frame that attaches to the tow vehicle's hitch. It is typically a "V" shape, with the pointy end of the "V" being the part that attaches to your vehicle.
The amount of downward force that the trailer's tongue (hitch attach point) exerts on the rear of the tow vehicle (trailer hitch) is called "tongue weight."
Tongue weight is something that RV designers take into consideration when they design a rig's layout. Where they place interior furnishing, appliances, slides, and even where they position the trailer's axle(s) directly impact tongue weight.
Also, how you load your RV will affect the weight at the trailer hitch. Put too much heavy stuff at the rear of the trailer, and tongue weight is lowered. Load up the front of the rig, and the weight applied at the hitch increases.
Some trailers are more sensitive to how they are loaded and will be significantly impacted by where you put stuff and even if the water and waste holding tanks are full or empty.
I've weighed my 24-foot travel trailer with both full and empty water tanks (the tank is forward of the axles), and there is a noticeable difference in the tongue weight measurement.
Having the proper tongue weight ensures the stability of your towed trailer as you head to your favorite camping spot. Take the time to understand how to calculate tongue weight so that you don't endanger yourself and others as you tow your home away from home down the interstate.
Tongue Weight vs. Hitch Weight
Is Hitch Weight The Same As Tongue Weight? While both terms are often used interchangeably, they aren't necessarily the same.
Tongue weight is the weight of the trailer that isn't supported by the trailer's axle(s). In other words, as explained above, it is the downward force exerted on the tow vehicle's hitch. This force is applied where the front of the travel trailer (tongue) attaches to the hitch ball.
Hitch weight is the tongue weight PLUS the weight of the hitch itself. So this is the total weight that is being applied to the tow vehicle's hitch receptacle (where you 'plug' in the hitch equipment to the vehicle you are using to tow your trailer).
There is an engineering standard that tow ratings (including tongue weight ratings) are calculated - SAE J2807 (initially issued in April 2008, so older vehicles won't comply with it). This standard allows for a certain weight for hitch equipment: 55-75 pounds depending on the maximum tow weight (source).
SAE J2807 Testing Briefly Explained
If your tow hitch weighs more than the allowed amount, the difference must be included in the hitch weight. Most weight distribution hitches fall within the allowed amount, so tongue weight is the same as hitch weight.
However, some hitches weigh considerably more than the allowed amount. For example, I use the Hensley Arrow hitch, which is 160 pounds. So I need to include the additional weight in the hitch weight calculations.
Why Is Proper Tongue Weight Crucial?
Improper tongue weight can damage the tow vehicle or cause loss of control due to trailer sway. Read on to learn about what happens if you have too little tongue weight or too much.
If the camper tongue weight is too light, there will be insufficient downward pressure where the trailer connects to the tow vehicle (aka the trailer coupler). This can cause trailer sway (or fishtailing), which can compound/amplify until you lose control, resulting in a crash.
Low weight at the front of the trailer can lead to bouncing (porpoising) your entire setup when you go over bumps or uneven pavement. This can unload the rear of your tow vehicle, resulting in loss of control, or at the very least, it makes for an uncomfortable ride.
In extreme circumstances, too little weight at the tongue of your trailer can also cause the front of the rig to lift, which raises the rear of your vehicle, reducing the grip/control of its rear tires.
See the below video to see what can happen when the tongue weight of your trailer is below what it should be.
If the weight at the tongue of the trailer is too much, excessive force can be exerted at the rear of the tow vehicle, potentially overloading the rear axle.
This can cause premature tire wear, tire blowouts, damage to the rear suspension, and if the weight distribution hitch isn't set up right, unloading of the front of the vehicle can result in steering control and braking problems.
Also, having the front of the trailer excessively heavy can mean that you exceed the maximum tongue weight of your tow vehicle, especially if you are already close to the max.
How To Adjust
If your trailer suffers from too high or low tongue weight, you must adjust it before hitting the road.
In theory, the trailer designers properly configured the layout so that tongue weight should be within the proper range when the rig is empty. Therefore the items you place inside will directly impact the weight.
The good news is if this is the case, you should be able to move stuff around to ensure that tongue weight is where it should be.
If the front of the trailer is too heavy, you will need to remove weight from the front of the camper or add weight to the rear (or a combination of both).
The freshwater tank of my camper is ahead of the axles, so when it is full, the tongue weight is increased. I try not to travel with a full fresh tank for this reason (plus, who wants to spend gas dragging water around if you don't have to?).
You may have to relocate heavy lead acid batteries, typically at the front of the trailer, or replace them with much lighter (but more expensive) lithium batteries.
Also, be aware of what you put inside any forward storage bays. Heavy cargo here will increase the weight at the front of your rig.
If there isn't enough weight 'pressing' down at the front of the camper, you will need to shift the interior load forward. Or put some heavier items in any available front storage bays. Or add another heavy battery to the front.
Keep in mind that you want to shift the weight in relation to the trailer's axle(s). Adding weight behind the axle(s) will decrease the weight at the front, and adding weight ahead of the axle(s) will increase the weight at the front.
How to Calculate Trailer Tongue Weight Ideal Range
The ideal range for a trailer's tongue weight is between 10 and 15 percent of the actual weight of the trailer. This is the loaded trailer weight when you are heading out to go camping.
Ideally, you will want to aim for closer to 12%, but you have the range of 10-15% to fall into.
It is not a percentage of the gross vehicle weight rating (the maximum weight the trailer can be) unless your trailer loaded for a typical trip is right at the max weight (not a good thing).
You will need to load your trailer up as if you were going camping and then weigh your trailer. Then you will measure your trailer tongue weight. You can get both of these weights at the same time.
Once you have this measurement, you multiply the weight of your trailer (previously measured) by 12% (the ideal weight) to see what the weight of your trailer tongue should be. Compare it to what you measured it to be.
If the stars are aligned in your favor, it is within the desired range. If not, make necessary adjustments and recheck.
Why You Need To Determine Tongue Weight
The recreational vehicle manufacturer will publish a tongue weight for your particular model and floor plan. Why can't you use this number and call it a day?
While the manufacturer goes through the steps necessary to determine the tongue weight, they don't necessarily do it on each unit. Yes, two rigs that are the same floor plan and model can have different overall weights due to varying options or a change in the supplier of appliances, etc.
Also, a factory tongue weight measurement is done on an empty trailer with no water in its tanks, no personal belongings, and empty propane tanks. Plus, with many rigs, the house batteries are added by the dealer, and since they are frequently at the front of the RV, they are a big contributor to the weight at the front.
In other words, the weight that the factory uses is often nowhere close to the weight of the RV as it is when you are towing.
So you MUST determine your actual trailer's weight.
How To Measure Trailer Tongue Weight
There are four ways to measure your travel trailer's tongue weight:
- Commercial scale
- Bathroom scale
- Tongue weight scale
- Weigh Safe Ball Mount
Of these methods, only one (commercial scale) allows you also to get the gross trailer weight (loaded weight) which you need to know to calculate tongue weight. Therefore, the Commercial Scale method is our top pick.
Commercial Scale Method
Once you have located a commercial scale (located at truck stops) and verified they would let you weigh your recreational vehicle, it's time to get busy!
Below we show you what steps to take if you only want to determine trailer tongue weight, but we strongly suggest you also figure out your trailer weight simultaneously. You will need this measurement to calculate proper tongue weight.
Figuring Out Tongue Weight Only
This requires two separate weighings. One with the trailer connected to your tow vehicle and one with just the tow vehicle (trailer not connected).
For the first weighing, press the call button and tell the clerk that this is your first weight.
They may ask you for your truck number. Just tell them that you are an RV.
Then, when taking your second weighing, be clear that this is a re-weigh.
Evidently, you may be charged the full price for the second weighing (re-weighs are usually cheaper) if you don't mention this.
Weigh As Follows:
- Weigh your tow vehicle with the trailer attached. Position your setup so the trailer axle(s) are on one weighing pad and your tow vehicle's axles are on another. This will give you two separate weights on the printout you will get at the end. When checking tongue weight only, you don't care about the trailer weight number - just the tow vehicle's weight. This is weight A.
- Drive off the scale and detach your trailer from your tow vehicle. Drive JUST the tow vehicle back onto the scale, ensuring it's on just one weighing 'pad.' (Tell the scale operator this is a 're-weigh' so you don't get charged the full amount for a second weighing.) This is weight B.
- Collect your weighing slips from the scale operator (you will get two slips). It's time to do the math! Subtract weight B (tow vehicle without a trailer attached) from weight A (tow vehicle with the trailer attached) to get the tongue weight.
How Do You Calculate Tongue Weight?
Calculating tongue weight is as simple as taking the two weights you figured out above and performing this simple calculation: Weight A - Weight B = tongue weight.
It's that simple!
Bathroom Scale Method
For this, you will need:
Do this on a level surface!
The above chart pretty well explains how to set up your scale system. Additionally, you can view the video directly below to see the process demonstrated.
The main constant is that you must put the tongue 1-foot away from the end that doesn't have the scale. The other side can be 2, 3, or even 4 feet away from the tongue.
Keep it at a 2-foot minimum. The spacing you choose determines how you do your math.
If you use the above scenario, you use a 2-foot scale-tongue gap and a 1-foot block-tongue gap.
Therefore, you have a 2:1 ratio. This means that the scale will only support 1/3 of the tongue weight.
In our example, where you use a spacing of 2 feet and 1 foot, you add the two distances together, which is three.
This is your multiplier. Your math will be to multiply what the scale says by three.
For example, if the scale says 220, then 220 x 3 = 660. Therefore your tongue weight is 660 pounds.
Say you use three feet in between the tongue and the scale, then you have a 3:1 ratio and will multiply the scale reading by 4 (3+1).
Thankfully, it's pretty simple math.
This method aims to keep the tongue weight from being directly on the scale and breaking it.
Most average-sized travel trailers will have more tongue weight than a typical bathroom scale can handle.
Measuring Tongue Weight With A Bathroom Scale
Tongue Weight Scale Method
These scales are made just for this purpose but can be pricey.
They are simple small scales made to take the weight of a trailer tongue up to the number of pounds they are rated for.
Place the tongue weight scale under the trailer coupler (you will have to use blocks to bring up the scale to the level of the coupler - see video below). Lower the trailer using the tongue jack until the entire weight is on the scale, and look at the reading.
When taking this measurement, you will want the trailer to be level from fore to aft.
Using A Sherline Scale
This is the simplest way of determining tongue weight, but it won't give you the actual weight of the trailer, which you need to calculate the actual tongue weight range for your exact trailer.
Weigh Safe Ball Mount Method
The Weigh Safe Hitch is a hitch with a built-in scale. It's as simple as that. You connect the trailer to the hitch, and you see the weight.
You have a reasonably accurate trailer tongue weight showing in the trailer hitch itself.
This option will be more expensive than the other methods but is also helpful as your tongue weight can change with varying cargo, water, and propane levels.
Using A Weigh Safe Hitch
Frequently Asked Questions:
Does A Weight Distribution Hitch Reduce Tongue Weight?
No, a weight distribution hitch doesn't reduce the measured tongue weight. This is because when you are measuring tongue weight with a weight distribution hitch, you do so when the hitch is not in weight distribution mode.
In other words, the hitch spring bars (or chains) are not under tension, and the hitch is not distributing weight.
It is true that when the weight distribution hitch is in towing configuration (distributing weight), it is redistributing some of the hitch/tongue weight (tow vehicle rear axle loading) to the front axle of the tow vehicle, and to a lesser degree, the trailer's axle(s).
However, the correct way to determine (weigh) tongue weight is to do so when the weight distribution hitch isn't distributing rear axle/hitch weight, so the hitch itself doesn't change the measured tongue weight.
What Happens If Trailer Tongue Weight Is Too Heavy?
If the tongue weight is too heavy, you can overload the tow vehicle's rear axle, which can result in a loss of control.
Can Too Much Tongue Weight Cause Trailer Sway?
No, too much tongue weight doesn't cause trailer sway. The opposite is true: Too little tongue weight causes trailer sway.
What Is The Recommended Tongue Weight On The Hitch Of The Towing Vehicle?
The recommended correct tongue weight is between 10 and 15% of the actual (loaded) weight of the trailer. The ideal tongue weight would be about 12% of the trailer weight.
Is 10% Tongue Weight Enough?
You want tongue weight between 10 and 15% of the actual trailer weight, so yes, 10% is enough, but on the low end. Ideally, you want approximately 12% of the actual trailer weight to be at the tongue of the trailer.
There you have it! Now you know what is tongue weight capacity and four different methods to measure it.
You will need to know the max tongue weight of your tow vehicle (that'll be in the owner's manual) so that you don't exceed it. In an ideal world, you will have a margin of safety, so you don't want to be right at the maximum allowable weight.
And you also learned the fine points of hitch weight vs. tongue weight, so you'll be the hit of the next cocktail party you attend. Or woo your significant other. (If this works for you, please comment below!)
Finally, you learned what an acceptable trailer tongue weight is and what can potentially happen if you are too heavy or too light at the front of your trailer.
Get to measuring before you hit the road, so your next grand camping adventure is safe for you and those other vehicles around you.
Author: Marshall Wendler
Camp Addict co-founder Marshall Wendler brings his technical expertise to help explain RV products in an easy to understand fashion. Full-time RVing from April 2014 - December 2020 (now RVing about 50% of the time), Marshall loves sharing his knowledge of the RV lifestyle. Marshall spends the majority of his RVing life boondocking. He is the part of Camp Addict that knows 'all the things'. He's good at sharing his technical knowledge so you can benefit.