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Old 02-16-2019, 07:58 AM   #15
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My thoughts are to hook up and tow and see how it does rather than obsessing over tongue weight. You either trust the builder to build with the proper weight ratios, and distribute your cargo evenly, or you don't. It ain't like you're going to be able to release pins on the axles and slide them forward or backward. If you're driving yourself nuts over whether you're in the "sweet spot" based on published standards you may need find something that's less stressful. The tongue weight is going to vary to some degree every time you load it.
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Old 02-16-2019, 08:07 AM   #16
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Another really easy way to get the trailer tongue weight. Pull thru the scales until the truck rear tires clear the scale, and the tongue jack is still over the scale. This way you get the TT weight only. After that. Drop the jack, and unhook. You get the TT, and tongue weight together. Subtract TT weight only from total with jack down on the scales. There you have the tongue weight.
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Old 02-16-2019, 09:49 AM   #17
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Originally Posted by Yellowcub View Post
My tires weigh 224#. My truck is not carrying those tires. Why would the weight of the tires be included in the weight of the truck.
Because GVWR includes the weight of the tires and wheels when the vehicle is sitting on the scale.

Payload capacity = GVWR minus the weight of the truck, including the tires on the truck.

If you replace the tires with heavier tires on the truck, the GVWR doesn't change, but payload capacity does change.
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Old 02-16-2019, 10:00 AM   #18
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[QUOTE=terryallan;4638187]Another really easy way to get the trailer tongue weight. Pull thru the scales until the truck rear tires clear the scale, and the tongue jack is still over the scale. This way you get the TT weight only. [quote]

Nitpicking semantics, but you don't get the weight of the TT, but only the weight on the TT axles. You can compare that weight with the combined GAWR of the trailer to determine if the trailer is overloaded.

Quote:
After that. Drop the jack, and unhook. You get the TT, and tongue weight together. Subtract TT weight only from total with jack down on the scales. There you have the tongue weight.
Nitpicking continued:

Weight on the trailer axles, plus weight on the tongue, = gross weight (GVW) of the TT.

Weight of the TT minus weight on the trailer axles = tongue weight (TW)
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Old 02-16-2019, 11:48 AM   #19
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[QUOTE=SmokeyWren;4638359][QUOTE=terryallan;4638187]Another really easy way to get the trailer tongue weight. Pull thru the scales until the truck rear tires clear the scale, and the tongue jack is still over the scale. This way you get the TT weight only.
Quote:

Nitpicking semantics, but you don't get the weight of the TT, but only the weight on the TT axles. You can compare that weight with the combined GAWR of the trailer to determine if the trailer is overloaded.



Nitpicking continued:

Weight on the trailer axles, plus weight on the tongue, = gross weight (GVW) of the TT.

Weight of the TT minus weight on the trailer axles = tongue weight (TW)
ain't that what I said?
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Old 02-16-2019, 12:03 PM   #20
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ain't that what I said?
No, you said "This way you get the TT weight only." But you don't get the TT weight. You get the weight on the trailer axles, but not the weight of the TT. But as I noted, it's semantics, and I know what you intended.
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Old 02-17-2019, 06:59 AM   #21
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Originally Posted by SmokeyWren View Post
No, you said "This way you get the TT weight only." But you don't get the TT weight. You get the weight on the trailer axles, but not the weight of the TT. But as I noted, it's semantics, and I know what you intended.

I guess I didn't word it correctly. But with the TT sitting on the jack on the scales. you have the entire weight of the TT. With the TT hooked up, and only the TT axles sitting on the scales you get only the weight the TT axles are carrying. Minus that from the total with the jack, and axles sitting on the scales. you get the tongue weight. Better?


I guess another way would be to stop on the scales with only the jack over the scales. Unhook, and drive the TV off. Leaving only the tongue weight on the scales. but that would only work if the entrance to the scales was level. All are not.
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Old 02-17-2019, 08:42 AM   #22
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Whatever you guys do, don't forget to add weight of the bottle of water you normally carry in the cup holder. You wouldn't want a false weight reading and be lulled into a false sense of security. At any rate, I'd suggest doing this exercise before you purchased the rig rather than a month down the road, find out you're 12 lbs over and have to go buy a new ton and a half dually diesel.
(I wonder how long its going to take before the wives catch on to what ya'll are doing.)
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Old 02-17-2019, 09:11 AM   #23
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Originally Posted by terryallan View Post
But with the TT sitting on the jack on the scales. you have the entire weight of the TT. With the TT hooked up, and only the TT axles sitting on the scales you get only the weight the TT axles are carrying. Minus that from the total with the jack, and axles sitting on the scales. you get the tongue weight. Better?
Much better. But since that requites two scale tickets, why not do it the normal way? One pass over the scale with the trailer hooked up but with the spring bars loose. Another pass over the scale without the trailer. Add the axle weights on the truck to get GVW. GVW with the trailer minus GVW without the trailer = tongue weight (TW).

Then gross combined weight of truck and trailer with the spring bars loose, minus the weight of the truck = gross trailer weight. Or to double check, weight on the trailer axles plus TW = gross trailer weight. Gross trailer weight is not useful for anything except to compute percent of tongue weight. To determine if the trailer is overloaded, compare the weight on the trailer axles to the combined GAWR of the trailer axles. But you need percent of TW (TW divided by gross trailer weight) to see if the wet and loaded trailer is properly loaded. You want 12% to 14% TW, with a goal of 13%. Less than 12% can result in the trailer being more prone to sway, and more than 14% is a waste of precious tow vehicle payload capacity.

With a third pass over the scale, with the trailer and with the hitch adjusted for highway travel, you can compare weights on all axles of the rig, with and without the spring bars tight, to see how much weight distribution your WD hitch is achieving. The goal is 20% to 25% of TW distributed to the front axle, another 20% to 25% of TW distributed to the trailer axles, leaving 50% to 60% of TW on the rear axle of the tow vehicle.

The percent of TW on the rear axle is determined by how tight you get the spring bars. If the remaining 40% to 50% of TW is not evenly distributed between the front and trailer axles, then you adjust that by changing the angle of the ball to the coupler. Every time you adjust that angle, you need another pass over the scale to see the results.
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Old 02-17-2019, 09:27 AM   #24
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My thoughts are to hook up and tow and see how it does rather than obsessing over tongue weight. You either trust the builder to build with the proper weight ratios, and distribute your cargo evenly, or you don't. It ain't like you're going to be able to release pins on the axles and slide them forward or backward. If you're driving yourself nuts over whether you're in the "sweet spot" based on published standards you may need find something that's less stressful. The tongue weight is going to vary to some degree every time you load it.
x2, it ain't rocket science.
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Old 02-18-2019, 12:32 PM   #25
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If it sways around there isn't enough. If it pulls like a lead anchor and the nose is low there is too much. After you pull trailers for a while you can tell without a scale.
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Old 02-19-2019, 05:25 PM   #26
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Originally Posted by fvstringpicker View Post
Whatever you guys do, don't forget to add weight of the bottle of water you normally carry in the cup holder. You wouldn't want a false weight reading and be lulled into a false sense of security. At any rate, I'd suggest doing this exercise before you purchased the rig rather than a month down the road, find out you're 12 lbs over and have to go buy a new ton and a half dually diesel.
(I wonder how long its going to take before the wives catch on to what ya'll are doing.)
Looks like you not only joined the "Weight Police," you've become a member of the Nazi Division of the Weight Police.
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Old 03-02-2019, 11:13 AM   #27
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Good morning my friends:

It's a relatively easy procedure to calculate the real, no joke tongue weight of a pull-behind on a receiver ball hitch, thanks to 'ole Archimedes back around 250 years or so BC. He was about the first to mathematically describe, or state the principle of a lever and fulcrum.

When we hook any trailer onto the ball on a receiver, what we have is a lever and fulcrum situation. In today's terms, Archimedes determined the "moment", or torque, applied to the lever arm on one side of the fulcrum must equal the "moment" applied to the other side of the fulcrum.

We can apply this to our situation to compute the tongue weight of our trailer. The lever is the truck, or the frame of the truck itself, from the receiver ball to the front axle. The fulcrum is the rear axle. One "arm" (distance from the fulcrum to the force, or weight on one end) is the wheelbase, or the distance between axle centers. This can be found in the owner's manual. The arm on the other side of the fulcrum that must be balanced is the distance from the fulcrum to the ball on the receiver hitch.

The "moment" is the force, or weight X the arm, or distance from the fulcrum to the weight. We have to balance the moment on one side with an equal moment on the other.

Example: Let's state our assumptions first.

The distance between axle centers is 16 feet (I'll call this our forward arm).
The distance from the rear axle to the receiver ball is 4 feet (I'll call this our rear arm).
From the Cat scale we have:
Front axle, trailer hooked: 3500 pounds, Without trailer: 3750 pounds.
Rear axle, trailer hooked: 5000 pounds, Without trailer: ?
Trailer axles, hooked: doesn't matter for now. We just want our tongue weight.

We took off 250 pounds from our front axle with nothing more than hooking our trailer. The moment is weight X arm (250 pounds X 16 feet = 4000 ft/pds moment). This moment must also be on the rear arm of the lever.

Therefore, if we divide the 4000 ft/pds moment by the rear arm (4 feet), we get 1000 pounds tongue weight that we must have in order to equal the 4000 ft/pds moment on the forward arm.

Now with the trailer hooked, we took 250 pounds off the front axle. Where did that go? It had to go onto the fulcrum, rear axle, along with the 1000 pounds of tongue weight increasing the gross rear axle weight by 1250 pounds. So, if we subtract the 1250 pounds that we must have added to the rear axle with the trailer hooked, we see that our rear axle weighs 3750 pounds without the trailer. And thanks to good 'ole Archimedes, we don't need a scale slip to tell us that.

I'll be glad to respond to any questions. Please don't hesitate to email me.

Dave
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Old 03-02-2019, 12:11 PM   #28
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Please allow me to qualify my previously posted comments on calculating tongue weight.

Certainly an LDH will change matters some. The gross combination weight will increase by the weight of the extra hitch hardware.

It's the balance, or axle weights that will change.

So in my basic, simple example posted previously, you need to weigh the combination without the LDH bars chained up if you wanted to know the accurate tongue weight.

However, knowing that is really of little value if you're pulling something large enough to require an LDH.

Adding an LDH in the mix is a bit more complicated than my basic example from earlier. But is still doable with the correct information from the Cat scale.

The main point to keep in mind is, no matter what your weights are, the "moment" on each side, fore and aft, of the rear axle must, by the nature of the beast, be equal.

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