Tongue Weight

[KenEllen]

How does one measure tongue weight?

[John in Michigan]

Over the past several years we have weighed all three FG trailers that we have owned at a state certified drive-on scale at a landscape supply store. In each case we drove onto the scale, then unhitched the trailer, then moved tow vehicle OFF the scale. Thus determined the total trailer weight. To determine the tongue weight, you could tow the trailer onto the scale, then move the tow vehicle off the scale. This would indicate the trailer axle weight. Then unhitch the trailer. This would indicate total trailer weight. Then subtract trailer axle weight from total trailer weight, resulting in tongue weight.

I was also able to check the tongue weight with a bathroom scale. This only works if the tongue weight is within the bathroom scale weight capacity.

[Iowa Dave]

There are at least two scales on the market
for checking tongue weigh. The Sherline with 1,000 lb dial resembles a small bottle jack. The jack comes with good instructions. Second is a post type scale that available and is probably less than half the cost of the Sherline. The people I know who have one and have used it and checked accuracy against the Sherline say it’s very good. It’s available at auto parts stores and some RV parts stores. Sorry I don’t have a name for the post type unit. Somebody will weigh in on this. ��I weigh our 21 when I get it ready for the season each spring at my local rock quarry and use the Sherline to determine the tongue weight at dead level towing height which I prefer. Weights don’t vary much year to year once you set up to camp your way but can creep up if you tend to accessorize. Mine personal weight tends to creep up when I candyize and beerize.
Iowa Dave

[AC0GV]

Originally Posted by KenEllen

How does one measure tongue weight?

You can use a bath scale to get the hitch weight, but it is better to know both hitch and total weight. Most RVs tow well at 10 - 15 % of the weight on the hitch. Be sure to weigh it at the height you tow it as it will change the weight a little. Here is the weight of my 2017 16' as built. (Deluxe, side dinette, with bath)

[minke]

Some people get ball mounts with scales, e,g,:


https://www.etrailer.com/dept.aspx?f...sort=-sb-Price

[gordon2]

I looked on the internet on how to measure tongue weight and then went to Goodwill and picked up a analog bathroom scale for $5 . It has max range of 300 lbs so its fairly accurate for tongue weights up to 200-220 or so, or you can use a leverage board as described on so many of those internet sites to measure higher tongue weights.

I had Sherline at one time also.. but the $5 bathroom scale was more than sufficient for a small fiberglass trailer.

[floyd]

I use a Health-O-Meter balance scale like in the doctor's office,
accurate to 350 pounds. similar to this...

[rubicon327]

Originally Posted by Iowa Dave

Second is a post type scale that available and is probably less than half the cost of the Sherline. The people I know who have one and have used it and checked accuracy against the Sherline say it’s very good. It’s available at auto parts stores and some RV parts stores. Sorry I don’t have a name for the post type unit. Somebody will weigh in on this.

https://www.ebay.com/i/192874481388?...UaAsTyEALw_wcB

[Jon in AZ]

I’ve never seen the post type before. Wondering if it might be too tall for some trailers, like my low-slung Scamp 13? There were no specs listed for this one.

[k corbin]

if you want to know the dimensions of a product just write a message to the seller.

[k corbin]

this etrailer article shows how to determine tongue ball weight with a bathroom scale and also at a weigh station scale.

https://www.etrailer.com/faq-how-to-...ue-weight.aspx


But something important to remember when doing it with a bathroom scale. You need to have the trailer sitting at the exact same height it will be when physically connected to your tow vehicle. A variance in that height during the weighing process will give you a false reading instead of the true tongue weight.

[Raspy]

Bathroom scales are not the last word in how to measure tongue weight at home, or the last word in predicting safety. They can be made to work, but their accuracy is seriously in question and the procedure must be done in a way to minimize inaccuracy. The balance type used in doctors offices or commercial settings are the best, but those are not "bathroom" scales.

At some point, the exact number is not that important anyway.

So many here claim tongue weight should be 10-15% of total weight for stability. That is a 5% variable, so if the weight was 300 lbs, 5% variability would be 15 lbs. My trailer has a factory spec tongue weight of only 7 1/2% of total, and it is very stable. So, the generally discussed number of 15% would be 50% off. I disagree when someone declares that one must have 15% to be safe.

My bathroom scale is known to be 10% off. And it also locks up if the weight is not evenly distributed across the surface. It is made to receive a load from two human feet. Putting the foot of the tongue jack on it, binds it up, so a distribution platform has to be built to make the scale work. In heavier settings, a fulcrum can be made to expose the scale to a percentage of the total, and then calculations done to get the total.

Then the cargo in the trailer and it's position in the trailer can vary wildly. My old toy hauler, for instance, had a 100 gallon water tank in the front. When full, it changed the tongue weight by nearly 800 lbs, compared to when it was empty! While on trips the tank weights change, as water was transferred, and the tongue weight constantly changes.

Bottom line, don't try to get an exact number and think it will make or break the safety or viability of your rig. Use common sense while loading the cargo. Be sure you have real numbers to work with in your initial measurements. Stay away from absolute proclamations that the weight should be "X" to be safe. Understand how to stop unwanted oscillating sway if it begins to happen, by applying the trailer brakes. Realize that some movement from passing trucks and gusts of wind is normal and OK. Watch your trailer carefully at various speeds and various conditions until you are confident of it's stability. If it seems too busy, or wants to wiggle at some speed, correct the problem with weight distribution, tire pressure, hitch height, or add a friction type sway bar.

If you need an accurate number, especially if you need that number repeatedly, get a Sherline scale. If your tow vehicle is bottoming out, you know you have too much tongue weight for it without even getting out the bathroom scale.

If you have instability at speed, maybe you have too much load on the back of the trailer. Adding weight at the rear will lighten the tongue, and possibly even bring it to your sought after 10%, or relieve some load on the tow vehicle, but it will also add a lot of potential instability. It is very unsafe to load the rear of the trailer, even if you end up with your desired tongue weight.

Tongue weight is not the entire story, or a very good predictor of stability. Measuring it inacurately gives you nothing.

[k corbin]

Think like an engineer, spread the load across a wider area instead of point loading the bathroom scale.

Put a wide board on top of the scale before you rest the tongue on it. Subtract the weight of the board from the results or if the scale allows for it zero the scale out with the board on top of it.

[Jon Vermilye]

Originally Posted by k corbin

Think like an engineer, spread the load across a wider area instead of point loading the bathroom scale.

Put a wide board on top of the scale before you rest the tongue on it. Subtract the weight of the board from the results or if the scale allows for it zero the scale out with the board on top of it.

You may also need a board UNDER the scale. I use a bathroom scale (500 pound limit) and while it works well on cement or asphalt, when I attempted to weigh some trailers on sand the feet sunk in, putting much of the weight on the bottom of the scale where it didn't register. I now carry a scale size piece of 3/4" plywood.

I made an adapter that sits on the scale and extends a post to a normal ball height.

You can also go to any CAT scale & make two weighings - one with the tow vehicle & trailer, which will give you axle weights for the trailer and front & back for the tow, and one with just the tow. A bit of math gives you trailer & tongue weight. I generally stop by a nearby CAT scale at the start of each trip - $12 for the first weigh, $2.50 for the second (truck alone).

[War Eagle]

In addition to our 17' EggCamper and 21' Escape, I also frequently tow farm implements and a wide variety of "stuff" in and on three different utility trailers, and the Sherline (1,000 lb. model) has been a good investment for me. It's compact and easy to take along to re-check tongue weight whenever I change the load. Our local Farmer's Coop (only 5 miles from our home) has certified drive-on truck scales, and they are happy to weigh for free any non-commercial trailers.

[mimie]

Originally Posted by k corbin

this etrailer article shows how to determine tongue ball weight with a bathroom scale and also at a weigh station scale.

https://www.etrailer.com/faq-how-to-...ue-weight.aspx

But something important to remember when doing it with a bathroom scale. You need to have the trailer sitting at the exact same height it will be when physically connected to your tow vehicle. A variance in that height during the weighing process will give you a false reading instead of the true tongue weight.

Great link and additional info, thank you!

[LarryB.]

Originally Posted by k corbin

.... You need to have the trailer sitting at the exact same height it will be when physically connected to your tow vehicle. A variance in that height during the weighing process will give you a false reading instead of the true tongue weight.

Last year, I calculated my TT's total weight at a scrap yard’s scale by weighing my TV and subtracting that weight from the combined weight of the TV & TT. I did that exercise using a standard hitch.

But, when camping with my TT, I use my Curt weight distribution hitch. How does that factor into calculating the tongue weight?

To calculate the tongue weight, do I need to weigh the trailer hitched up on the WDH with the TV off the scale and then subtract that from the weight above?

Originally Posted by John in Michigan

... To determine the tongue weight, you could tow the trailer onto the scale, then move the tow vehicle off the scale. This would indicate the trailer axle weight. .... Then subtract trailer axle weight from total trailer weight, resulting in tongue weight.

[Civilguy]

Originally Posted by LarryB.

To calculate the tongue weight, do I need to weigh the trailer hitched up on the WDH with the TV off the scale and then subtract that from the weight above?

The tongue weight of the trailer is best measured with a separate scale. You just measure the weight that would rest on the ball of a "regular" hitch, also described as a "weight-bearing" hitch.

When a weight-distribution hitch is employed, tongue weight isn't measured with the weight-distribution function active.

The forces involved when you cinch up the spring bars are beyond most people's interest. If you're curious, you can see more here and on similar forum posts:

https://www.caravanersforum.com/viewtopic.php?t=68129

[Civilguy]

Originally Posted by KenEllen

How does one measure tongue weight?

There's a good illustration and explanations here.

https://www.etrailer.com/faq-how-to-...ue-weight.aspx

[Bruce H]

Keep in mind tongue length trumps tongue weight.