The tongue weight is one of the most important limits to consider when towing anything – in simple terms, it is the total weight that the trailer tongue exerts downwards on your trailer hitch. When this hitch component happens to be a ball mount and a ball, this measurement is also often referred to as the ball weight.
The tongue weight plays an important role in the balance and safety of your tow setup. One of the main causes of excess tow weight is improper weight distribution, and once you get past the limits of what the trailer hitch can safely support, that’s the point where you start running into potentially dangerous issues.
The tongue weight is the actual weight being exerted by the trailer tongue. The trailer tongue is the extension from the trailer, which forms an arm that connects to the tow vehicle’s receiver or ball.
In general, the tongue weight of a proper tow setup should never be negative – that is, the trailer should lean forward if it’s unhitched, with the tongue being forced by gravity towards the ground. A trailer that droops forward to the ground will have most of the weight loaded in a way that most of it are placed in front of the trailer axle.
How Your Trailer Relates To Tongue Weight...
A typical loaded trailer should have around 60 percent of its weight placed somewhere in front of the trailer in order to maintain some tongue weight. The actual tongue weight that gets transmitted to the tow ball or the receiver as a downward force depends on the amount of weight placed in front of the trailer axle.
It also depends on the distance the center of mass is placed relative to the axle, too. The farther forward the majority of the trailer cargo weight is placed, the higher the tongue weight relative to the gross weight of the trailer.
Most trailer manufacturers and towing experts recommend that trailers should be loaded in way that around 9 to 15 percent of the gross trailer weight is transmitted to the trailer tongue as the tongue weight.
The exact proportion depends on the type of trailer hitch and trailer that you have. Weight-bearing hitches, for example, will usually have a lower maximum tongue weight compared to load distributing hitches.
Tow vehicles, tow hitches and the trailers themselves also have what is known as a tongue weight rating. The tongue weight rating is the maximum weight that a tow component can safely carry as the trailer exerts its downward force on it.
This is a different, separate metric from the tow capacity rating or weight distribution rating of your towing component. For example, your trailer hitch that is rated for a tow capacity rating of 5,000 pounds will also have a separate tongue weight rating of around 500 pounds.
As a general rule, the tongue weight rating is less than the tow capacity rating of a component. Your typical trailer hitch, receiver or tow mount will usually have a tongue weight rating of around 10 percent of its tow capacity rating, barring a few exceptions of course.
Your tongue weight, then, is the actual weight of the trailer at the tongue, which you can measure with a trailer scale. You can also get a good estimate of the tongue weight of your trailer if you have a good idea of what your gross trailer weight is.
The tongue weight will change depending on a few factors. You can have a different tongue weight depending on the placement of the cargo inside your trailer. Of course, the tongue weight will also increase the more weight you add to your trailer if you place the additional weight in front of the trailer axle. The tongue weight can also change depending on the rise height of your trailer or hitch, as well.
The tongue weight rating of each of your tow components, however, remains constant, and you can check their ratings as specified by the manufacturer. Based on the tongue weight ratings of your tow gear and vehicle, you can also figure out the tongue weight rating for your entire tow setup as well.
Why Is Tongue Weight Important When Towing?
The tongue weight is important when towing since it directly affects the balance of your tow setup. Since the force exerted by the tongue weight acts directly on the flexible link between the tow vehicle and the trailer, then a certain level of tongue weight can cause the coupling to sit straight level, dip down at a downward angle, or be at an upward angle.
Excessive Tongue Weight:
Obviously, a coupling link that dips down is a dangerous thing to drive around with. The link can dip down low enough to hit the ground if the driver applies the brakes, or it could cause the front tires of the tow vehicle to momentarily clear the ground.
A situation like this, where the tongue weight is too heavy for a balanced tow setup, can impair the steering of the tow vehicle which might lead to an accident, or at least an unpleasant driving experience.
It will also cause a lot more stress on the rear axle of the tow vehicle, as well as the tow components you have installed. Your rear axle bears more of the weight, and the rear tires of your tow vehicle also wear out more. Since the coupling link dips down due to the excess tongue weight, your trailer hitch, tow ball, trailer tongue, and other components are also subjected to unnecessarily higher loads as well.
Not Enough Tongue Weight:
You might think, then, that a light tongue weight will fix everything, balance-wise, with your tow setup. Surprisingly, a tongue weight that is too light for the trailer weight can also pose problems, as well.
If your trailer cargo is distributed in a way that most of it are placed behind the trailer axle, then it may cause the coupling link to dip up. This may cause issues, again, as you brake or decelerate. The driving issues can get worse if your trailer does not have its own braking system.
A trailer that has a tongue weight too light can also lead to a dangerous situation called trailer sway. Loading your trailer such that it is heavier in the rear can lead to the trailer swaying as you try to take turns since the rear weight tends to counteract the direction that the tow vehicle is trying to turn to. When the imbalance is bad enough, this can lead to what is known as whipping – an uncontrollable and potentially violent sway that might even lead to the trailer getting overturned.
Even a slight wobbling motion caused by an imbalanced trailer can quickly escalate to dangerous whipping once you reach a certain speed, or if you happen to pass large trucks or similar vehicles going the other direction. If you notice trailer sway starting to develop, then you need to quickly rein it in before it can lead to a dangerous situation for you, your passengers, and other vehicles on the road.
Your first step to control trailer sway should be to ease off the gas pedal while keeping the steering wheel straight and steady, and wait for the vehicle to slow down to a speed at which the wobbling stops. As much as possible, you want to let the vehicle and its trailer to slow down by itself, without applying your brakes as much as possible.
Once you have the trailer sway under control, you should stop as soon as possible so you can redistribute the weight inside your trailer.
Load Your Trailer Correctly:
To avoid having a rear-loaded trailer, you need to make sure that you load your trailer in a way that 60 percent of the cargo weight is placed in front of the trailer axle. Most trailers are designed so that their cargo bay lets you easily accomplish this, so trailer owners should load cargo inside the compartment as much as possible. On the other hand, loading heavy cargo on the outside of the trailer, particularly out the rear, can potentially cause tongue weight issues.
A tongue weight that is well within the tongue weight capacity of your weakest tow component, combined with matching rise heights for both the trailer hitch and the trailer coupler, will result in a towing setup that sits straight and level. It will be a setup that is well balanced among the axles of the tow vehicle and the trailer, and it will not buckle down, dip up, or wobble whenever you brake or accelerate.
In short, it will be a well-balanced setup that will be a lot safer for the driver, passengers, and everyone else on the road. It’s also a tow setup that will be fun to drive with, and it will not add unnecessary wear and tear to the tow vehicle as well.
How To Calculate Tongue Weight?
The most accurate way to calculate the tongue weight of a loaded trailer or RV is to measure it using a tongue weight scales. Towing experts familiar with the trailer and the way the load has been distributed can make a fairly accurate guess by looking at the way the trailer behaves once it is hitched, but a tongue weight takes all the guesswork out completely.
A tongue weight scale is a portable device that directly measures the downforce exerted by a loaded trailer at the tongue point. To measure the tongue weight with a tongue weight scale, first you will need to park the trailer on a hard level surface and prop up the trailer tongue with a tongue jack. Then, you slide the scale under the trailer tongue, right at the spot where the tongue arm goes on to the tow mount ball.
Once the scale is in place, you can then crank down the trailer jack until the tongue weight is supporting the full weight of the trailer. At this point, you can put the trailer jack out of the way and get a reading.
A Tongue Scale Can Be Helpful:
A tongue scale is one of the easiest ways to measure the actual tongue weight of a loaded trailer. The alternative is to haul the trailer all the way to a commercial weigh station, or you can also rig together a tongue weight scale using a piece of lumber and a heavy duty floor scale. Some people would even use a bathroom scale for this in a pinch.
To calculate the recommended tongue weight to target for your trailer, you just need to use your gross trailer weight and a simple formula. Most manufacturers will recommend a percentage of the GTW as the recommended tongue weight. For example, a trailer with a GTW of 3,000 pounds multiplied by 10 percent as recommended by the manufacturer should have a tongue weight of around 300 pounds.
Where To Find Your Maximum Tongue Weight
To find the maximum tongue weight that your setup can carry, you need to look for the weakest link in your tow setup. The maximum tongue weight that a component can carry is usually listed as its tongue weight rating. For the tow vehicle, the tongue weight rating and related information can usually be found on the user’s manual.
The tongue weight rating for a trailer hitch is usually found on an information plate, or engraved on the side. The same goes for any receiver attachment you use, which will usually be a tow ball mount or a similar accessory. The trailer itself will also have its tongue weight rating listed in the owner’s manual, as well.
List down all the tongue weight ratings for the towing components that you plan to use. The maximum tongue weight for your setup generally should not exceed the lowest tongue weight rating you have.
How To Reduce Tongue Weight
To reduce the tongue weight, the easiest method is to redistribute the weight of the load. By placing some of the weight directly over the trailer axle, or behind it, you can reduce the tongue weight while still towing the same gross trailer weight.
Another way to reduce tongue weight is to simply reduce the cargo that goes in the trailer. You can put some of them in the tow vehicle, or you can just leave them behind.