5th Wheel Pin: How Do I Find Out The Trailer King Pin Weight?

Many times RV owners want a nice neat equation so they can figure out their weight capacities without any hassles. Unfortunately, there is no magic formula when it comes to getting accurate weight measurements. You will have some hassles involved.

The best and only way to get an accurate 5th wheel king pin measurement is by going to what is called CAT scales. You will have two measurements to take. One is the truck without the 5th wheel and one with it. Other than that you are merely estimating and that could be risky.

To learn more about this topic just continue to read our article. It has the information you want to know about so you know how to get accurate weight measurements before you hit the road. Staying underweight is vital.

What is The Pin Weight On a Fifth Wheel?


The first thing you need to be aware of is that you cannot get an accurate measurement by looking at the hitch or assuming what it might be. Both methods will not provide any sort of pin weight.

The pin weight is the amount of weight the trailer puts on the 5th wheel hitch and pin when hooked up. This weight must be 20% of the total trailer weight or you will experience some towing difficulties.

If you go under 15% of the weight of the trailer, you would be too light and your 5th wheel may look like a porpoise swimming in the ocean. The 5th wheel will be bobbing up and down as you drive along the highway.

Then you may know this term through one of its other names. It is also called king pin weight, hitch weight, or tongue weight but the latter is more for a travel or bumper pull trailer.

There are possibilities that you can go to 25% of the total trailer weight when you hook up to the tow vehicle but that is the uppermost limit you can go. It is best to stay around the 20% level to be on the safest side of towing a 5th-wheel trailer.

How do I Find Out The Trailer King Pin Weight?

Unfortunately, there is only one way to do this measurement and get the right results. Unlike bumper pull trailers, you cannot hook up a scale and see what the pin weight is.

Bumper pull hitches can come with tongue weight scales that help you see if you are over the tongue weight or not. With measuring the pin or king pin weight, you are not going to be so lucky.

The way to get the actual pin weight is one of two ways. First, you drive your truck to the CAT scale and get it weighed. Then you go back and hook up your 5th wheel and go back to the same scales and get weighed again.

Or you can drive to the CAT scale with the 5th wheel attached, get weighed, then drive a little into the parking lot or empty space and drop the trailer. After the trailer is off the hitch, go back to the scale and weigh the truck.

After you get the two weights, you subtract the lesser from the greater totals and you have your pin weight. Make sure to have both axles weighed so you get a very accurate weight measurement.

There is one catch when you go to weigh the 5th wheel and your truck together. You have to be fully loaded with supplies, equipment, and passengers or you are not getting an accurate weight measurement.

5th Wheel Pin Weight Percentage


This is important to know as pin weight is a vital part of a good towing situation. This is as important to know as tongue weigh this when you are pulling a bumper pull trailer.

If you fall outside the range of acceptable weight on either side of the scale, you are asking for trouble when you tow. The percentage for the pin weight has been stated at 20%.

So if your trailer weighs 14,000 pounds empty, your empty pin weight will need to be 2800 pounds. But since you need equipment, supplies, and passengers, you would need to add those in to get the actual trailer and pin weight.

As an example ONLY, if your passengers, equipment, and supplies add another 1000 pounds to your trailer weight, then your pin weight can only be at 3,000 pounds.

Now, there are some people who extend this percentage to provide a range of weights to make towing more fun or whatever reason they may have. They say you can go as low as 15% and as high as 25% of the total trailer weight.

You can do the math with the example we provided. The bug in the ointment will be your tow vehicle’s combined tow rating. You have to make sure that the total trailer weight and the total truck weight do not exceed this rating. Plus, you should make sure not to exceed the payload weight rating either.

When it comes to towing, weight capacities are numerous and they must all be met. What that means is that you need to be good at math or a family member needs to be good at math. It is not trigonometry but it is still important math.

How do You Calculate Pin Weight On a 5th Wheel?

The only thing we can do here is to be blunt. There is no magic formula, no equation, or calculation that you can do outside of going to the scales and getting weighed. If someone tells you there is, they are either lying or misinformed. We suggest going with the latter when telling them their mistake.

The only formula or equation you have to get the accurate pin weight is the weight of the trailer-less truck subtracted from the weight of the truck, trailer, cargo, etc., combined.

When you do that simple math equation, you then multiply the combined weight by 20% to get the pin weight you need to meet. When you see you are too heavy, you have to practice the game of what can you vacation without.

If you are too light, you can see what items will be useful and needed on your trip and put them in storage somewhere in the trailer or the bed of your truck (if there is room).

Of course, you can try the 15 to 25% option and see how your towing experience goes. You can always make adjustments as you tow or for the next trip.

5th Wheel Pin Weight Calculator


The internet is full of interesting websites that provide the needed devices or aid you need. You will find these 5th wheel pin weight calculators on many websites dedicated to talking about 5th wheel trailers.

We will link to three of them so you can access them easily. Just follow their instructions to see if they will be accurate for you or not. We will not make any guarantees or warranties that these calculators will be accurate or even helpful.

You use them at your own risk. One may only be good for bumper pull trailers so make sure you pick the one that will get you your maximum and safe pin weight. The first website is here, the second one is here, and the third can be found at this link.

Does Pin Weight Count Toward The Payload?


It is time for some bad news. Yes, the pin weight counts toward your payload weight capacity. What that means is that you have to go to your owner’s manual and find the payload weight rating.

Or it may be placed on a sticker on the driver's door, as well as the glove box. Once you get the payload weight rating, you need to subtract the pin weight from that.

If your total remains on the positive side of the scale, you can add some items to your truck or truck bed. But do not go overboard as you cannot exceed the payload weight rating.

If the pin weight lands on the negative side of the scale, then you have to either remove items from the trailer to lower the pin weight or redistribute those items so the weight is placed on the trailer’s axles.

If you are thinking of buying the 5th wheel trailer whose pin weight will be too heavy for your payload weight rating, then you cannot buy the trailer. It can be a difficult choice to make.

Some Final Words

No matter what it is called, the pin weight is very important. Not just because you need to tow the trailer but because you have to make sure your truck’s axles can handle the extra weight.

When it comes to towing, you cannot leave any item’s weight off the list or ignore any of the many weight capacities. Towing any type of trailer gets complicated at this stage.

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