When you are making your first forays into the world of RVing, many things are expected to be unknown to you, it is the nature of being a novice. Some of those things are very important for the safety of towing a trailer, such as how to calculate tongue weight.
So, how exactly do you calculate tongue weight?
Appropriate tongue weight is very easy to calculate, it should be 10% to 15% of your gross trailer weight (GTW). However, to get the actual tongue weight of your trailer, you will have to measure it using a commercial scale, tongue weight scale or even a bathroom scale is an option.
There are several ways to go about this, but before that, let’s cover what is the tongue weight and why it is important.
Definition of Tongue Weight
Tongue weight is the part of the trailer’s weight that is directly carried by the tongue of your towing vehicle. When two vehicles are connected to each other by hitch, you can think of them as if the trailer is leaning on the towing vehicle. Just like when someone is leaning on you, physically, part of the weight is transferred to the towing vehicle.
This weight is different from the pin weight, and it is a characteristic of trailers that are towed by a conventional hitch. While the pin weight is a characteristic of the 5th wheel trailers. But on the other hand, both of these can be called hitch weight, because while these trailers use different types of them, they are still types of hitches.
Tongue Weight Importance
Tongue weight is important to know for two reasons:
- towing safety
- towing vehicle limits
When you are towing a trailer, you want to do it as safely as possible, so the weight distribution of the trailer should be done properly. There should be more than half of the trailer’s weight in its front half because when isn’t, the trailer can easily start behaving like a pendulum. And calculating the tongue weight will give an estimate of when the weight is properly distributed.
All vehicles have certain towing limits, and they depend on the construction of several of their parts. One of those limits is the maximum tongue weight they can carry. So, knowing the exact tongue weight of a trailer, and in which range it is desirable for it to be, will tell you whether such a trailer can be towed with your vehicle.
You will see in many places the recommendation for tongue weight to be 10%-15% of the trailer’s weight, and this is not without a reason or some arbitrary number. This number can be achieved only if around 60% of the trailer’s weight is in its front half. If you don’t hit this range, be certain that more than half of the weight is in the back.
Towing is safe when the trailer is front-heavy, granted the towing vehicle puts a limit on how much that should be. Back-heavy trailers behave like pendulums, which is not safe. You could presume that going above 15% of trailer weight on the tongue could be safer, but it is not. Higher percentages will cause the towing vehicle to squat, which makes the front wheel lose traction.
Thus, the towing vehicle will severely understeer. So, keeping the tongue weight between 10%-15% is a balance between the safety of towing and the safety of driving. And overall, the safest situation.
How To Calculate Appropriate Tongue Weight
Because you need to calculate what is the sweet spot range between 10 and 15 percent, all you need is to calculate these percentages from the weight of your trailer.
This is where you should aim for your tongue weight to be. If you have access to commercial truck scales, you can easily weigh your trailer. The math of calculating the desired tongue weight is very simple, and you should start by calculating 10%. Whether you will actually calculate the number on a calculator, or just put a decimal point one place from the right, it doesn’t matter.
By multiplying this number by 1.5 you will get a 15% number. To get the actual tongue weight of your trailer, you will have to measure it.
How To Measure Actual Tongue Weight
There are a few ways to measure a tongue weight of a trailer:
- commercial scales
- tongue weight scales
- bathroom scale
Measuring the tongue weight with commercial truck scales is very simple, you need to weight your towing vehicle with the trailer hitched to it, and then without the trailer.
Tongue weight you will get by subtracting the second number from the first. Tongue scales can be integrated with the ball mount or stand-alone, but in both cases, you can just read out the tongue weight.
With bathroom scales, you will need to macgyver a contraption for weighing. First, you need 6 feet 2×4, two 6-inch long 1-inch pipes, and cinder and wooden blocks in sufficient amounts to place the scale 3 inches below the hitch height. First, you need to mark the 2×4 one and a half feet from any end, this is the mark where you need to center the trailer’s tongue.
Next, you need to build two stable bases, one for the scales on which you will put one pipe and the other where there is just the pipe. On these pipes goes 2×4, and the scale pipe should be 4 feet from the mark, while the other pipe needs to be 1 foot. When you place your tongue on the mark, the scale will read a quarter of the weight.
Adjusting Tongue Weight
When you measure the tongue weight, there is no guarantee that you will be in the 10%-15% range, so you will have to adjust it. This is done by simply redistributing the weight around the trailer. If you are under, you need to move some heavier cargo to the front and replace the lighter items with them. But, if you are over, you need to do the opposite, move heavier items to the back of the trailer.
When towing, it is best to do it in a safe manner, and to do so you need to know how to calculate the tongue weight of your trailer. Towing is safe when it is in the 10%-15% range, so you need to calculate these percentages if you know the exact weight of your trailer. But, for the exact tongue weight, you will have to weigh it.
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(Featured image: forestriverinc.com / Independence Trail)
Erick is a freelance writer and outdoor enthusiast. Growing up in Nairobi Kenya and now calling Glasgow, United Kingdom home. Sipping on homemade spiced swahili tea and enjoying a good book is his idea of bliss.