Why weigh our vehicles - first topic TONGUE WEIGHT

[A W Warn]

Since I have been a member of the Forum I have been involved in several discussions about weighing our tow vehicles and trailers. To discuss what we are trying to accomplish when we weigh, the proper way to describe the results, and why all of this is so important will be the purpose of this thread. I hope every aspect of weighing will be discussed!

Let's start with the definition of trailer TONGUE WEIGHT, since it seems to be disagreed upon more often than any other.

Recently I got involved here: (http://www.airforums.com/forums/f238...ts-121859.html).
Instead of continuing to hijack mikekey's thread about sharing our trailer weights with each other, I thought we might continue the discussion in this thread.

Since my last post about weight measurements, #75 on mikekey's thread, I have been searching the internet for several hours in the last two days trying to determine what the definition trailer TONGUE WEIGHT really is. Some other Forum members have claimed that some hitches, the PP and HA specifically, when attached to the trailer A-frame assembly become part of the tongue weight. I see the logic in this, but do not agree.

What I found during my online search: As described by tow vehicle manufacturers, hitch manufacturers, and trailer manufacturers, the following are gleaned from some manufacture's published documents which I found online. The part between "quotation marks" is the exact wording from the manufacturer's document. Where there was a drawing in lieu of wording, the wording with no quotation marks is my description of the manufacturer's drawings.

DESCRIPTION OF TONGUE WEIGHT BY MANUFACTURER

From Ford Owners Manual – 2014 F-150
“Tongue Load or Fifth Wheel King Pin Weight - refers to the amount of the weight that a trailer pushes down on a trailer hitch.”

From Chevrolet Owners Manual – 2014 Silverado 1500
I found no written description of tongue weight in the manual, but there is a drawing in the Owners Manual showing tongue weight measured with a scale beneath the trailer tongue jack.

From Dodge Owners Manual – 2014 Ram 1500
“Tongue Weight (TW) The tongue weight is the downward force exerted on the hitch ball by the trailer tongue.”

From Toyota Owners Manual – 2014 Tundra
“Tongue Weight The load placed on the trailer hitch ball.” In addition to this description, there is a drawing in the Owners Manual showing tongue weight measured with a scale beneath the trailer tongue jack.

From Pro Pride Hitch website – Towing Definitions
“Tongue Weight (TW) – The static downward force exerted on the hitch ball by the trailer coupler.”

From Reese Hitch – 2014 Towing Vehicle and Vehicle Accessory Application and Technical Guide
“Tongue Weight (TW) is the downward force exerted on the hitch ball by the trailer coupler”

E-Hitch website – how to determine your tongue weight
“tongue weight. This is the weight that the fully loaded trailer exerts downward on the hitch ball of the tow vehicle.”

From Airsteam Owners Manual - 2014 Classic
I found no written description of tongue weight in the Owners Manual, but there are two drawings showing tongue weight measured with a scale beneath the trailer tongue jack.

From Forest River website – Travel Trailer/Fifth Wheel Towing Guide
“Tongue Weight -The weight of the tongue as it bears down on the hitch of the towing vehicle.”


The following statements are mine, but based on the facts, as I understand them, that I have read in manufacturer's published data. I invite you please comment (without getting into hostile arguments, let's keep it civil as possible) If you disagree, please provide manufacturers' published data or some reliable source to support your statements:

1. Manufacturer's written or drawn information (without exception that I have found) for tow vehicles, hitches, and trailers indicate the definition of TONGUE WEIGHT is the vertical dead weight of the trailer tongue where it bears on the ball and/or hitch.
2. The purposes of determining trailer TONGUE WEIGHT:
   1. To determine if trailer TOUNGE WEIGHT exceeds the weight capacity as designed by the trailer manufacturer.
   2. To determine if the trailer TOUNGE WEIGHT exceeds the ball manufacturer's specified weight for the ball. Every ball has its own separate rating for trailer TONGUE WEIGHT.
   3. To determine if the trailer TOUNGE WEIGHT exceeds the hitch manufacturer's specified weight for the hitch. Every hitch has its own separate rating for trailer TONGUE WEIGHT
   4. To determine if the sum total of the TOUNGE WEIGHT, weight of the ball, weight of the hitch, and weight of the sway control exceed the capacity of the tow vehicle's hitch receiver.
3. Dead weight of the hitch ball, the hitch, and/or sway control never becomes part of trailer TONGUE WEIGHT.
   1. Exception: The weight of any part of a hitch or a sway control which is permanently welded or bolted to the trailer, left in place when the ball and hitch are disconnected and/or removed from the trailer, does become part of the trailer TONGUE WEIGHT.
   2. When it is not practical to remove the ball and/or hitch when measuring the trailer TONGUE WEIGHT on a scale, the weight of the hitch and ball must be deducted from that weight when calculating trailer TONGUE WEIGHT.
   3. The ball, hitch, and sway control devices are cargo, which is added to and/or becomes part of the tow vehicle's payload weight.
   4. The sum total of the TONGUE WEIGHT and the weight of ball and hitch is used to determine the load on the tow vehicle's hitch receiver. I do not know the proper name (or terminology) for this sum total weight, but I do know it is not trailer TONGUE WEIGHT.
4. Dynamic or live loads are not used additionally to calculate or adjust the dead load of TONGUE WEIGHT.
   1. Rotational loads of torque on the ball, hitch and/or receiver, created by tensioning the weight distribution, are not considered when measuring trailer TONGUE WEIGHT.
   2. Vertical loads, created by tensioning the weight distribution spring bars, downward on the hitch ball and/or downward on the brackets mounted on the A-frame, are not considered when measuring trailer TONGUE WEIGHT.
   3. Transferred loads, weight transferred from the rear axle of the tow vehicle, then distributed onto the tow vehicle front axle and trailer axles, are not considered when measuring trailer TONGUE WEIGHT.

[A W Warn]

I got a PM, from a fellow forum member, telling me to "keep it simple". I whole heartedly agree.
Though, it takes a lot of "blah blah" to refute incorrect info that has been put forth elsewhere in this forum. It enables one to get to that point of information that should be so simple.

[HowieE]

Tongue Weight. It all depends on who and what they want it to define. The manufactures Tongue Weight is the load extended to the ball as the unit left the factory. Other than that day that number is useless and nothing more than an advertising statement. Every trailer out there has had modifications to the trailer that change that number. Gas tanks, WD hitch assembly, electric jack, plus load inside the trailer all effect the tongue weight. You are interested in the resulting weight before you leave the house

What you should be interested in is the weight placed on the ball before you make any adjustments in the hitch. That is the number that tells you if you have exceeded the receive rating or axle bearing ratings. While you can reduce the weight on the rear axle with hitch adjustments you want to be sure that the net number is within the 10 to 12 % of the gross trailer weight to insure proper handling while towing. Yes a WD hitch will effect sway but there is no reason to go beyond the accepted design recommendations.

PP and HaHa discount the fact that their hutches are included in the tongue weight. That is smoke and mirrors. That 100+ pounds is loaded directly on the TV.

Vehicle manufactures only give suggestions for tongue weights limits based on coupling to ball loads and do not take any form of WD hitch into consideration.

[dkottum]

Tongue weight. I think keeping it simple is

1) What is the tongue weight for selecting weight distribution bars?

I want to be able to distribute an equal amount to our 2012 Ram 1500 axles (some will go to the trailer axles). Add the Airstream hitch weight from their specification, my ProPride hitch weight, and anything we may carry in the truck's bed behind the rear axles. These are the weights the w.d. bars should be able to distribute, so we need ProPride 1400# w.d. bars. We get a smooth ride with good handling and braking in varied weather and traffic conditions.

2) How much does the loaded Airstream add to the loaded truck payload?

Pull the truck and Airstream onto a truck scale so the truck's axles are on, but the Airstream's axles are not. Weight distribution set and trailer level. Weigh it. Then disconnect the hitch from the truck and weigh again. The difference is the payload the trailer adds to the truck.

[A W Warn]

Originally Posted by HowieE

PP and HaHa discount the fact that their hutches are included in the tongue weight. That is smoke and mirrors. That 100+ pounds is loaded directly on the TV.

THANK YOU for responding!
That is exactly one of the points I was trying to make. Load of the hitch is on the tow vehicle as payload, not on the trailer tongue.

Originally Posted by dkottum

Tongue weight. I think keeping it simple is

1) What is the tongue weight for selecting weight distribution bars?

I want to be able to distribute an equal amount to our 2012 Ram 1500 axles (some will go to the trailer axles). Add the Airstream hitch weight from their specification, my ProPride hitch weight, and anything we may carry in the truck's bed behind the rear axles. These are the weights the w.d. bars should be able to distribute, so we need ProPride 1400# w.d. bars. We get a smooth ride with good handling and braking in varied weather and traffic conditions.

2) How much does the loaded Airstream add to the loaded truck payload?

Pull the truck and Airstream onto a truck scale so the truck's axles are on, but the Airstream's axles are not. Weight distribution set and trailer level. Weigh it. Then disconnect the hitch from the truck and weigh again. The difference is the payload the trailer adds to the truck.

THANK YOU for responding.
1) Good point! I missed mentioning the selection of spring bars based on tongue weight. That should have been item 5 under the purposes for determining tongue weight.
Though, I've do not remember reading that one should include the weight of the hitch in addition to tongue weight when selecting those bars! Can you point me toward PP's literature that says to do this? I have read their install guide, but not much else. I might have missed it.

2) I've weighed many times, so I'm familiar. Still, I'm hoping to learn more and share what I have learned. This will come up again in a future topic in this thread.

One of my goals: when this thread is done, someone new to towing can come here, read through and learn quickly. And, be able to take what they learn and quickly apply it.

[youngpeck]

Originally Posted by A W Warn

THANK YOU for responding!

One of my goals: when this thread is done, someone new to towing can come here, read through and learn quickly. And, be able to take what they learn and quickly apply it.

That would be me, and I thank all of you for your time, insight, and shared experiences.

I know after reading this thread (and others) that I'll get it right!

[A W Warn]

[QUOTE=dkottum;1479757]Tongue weight. I think keeping it simple is

1) What is the tongue weight for selecting weight distribution bars?

I want to be able to distribute an equal amount to our 2012 Ram 1500 axles (some will go to the trailer axles). Add the Airstream hitch weight from their specification, my ProPride hitch weight, and anything we may carry in the truck's bed behind the rear axles.
QUOTE]

Doug,

Thanks for pointing something out to me that I did not know. At first I thought you were saying adding hitch weight to tongue weight was unique for hitches like the PP or HA. I was wrong! After corresponding with Sean at PP and researching online I realized what you were trying to tell me. Your statement made me learn I have been calculating incorrectly for as long as I have been using weight distribution. (30+ years). Luckily I had the correct spring bars, even though my calculations were wrong!

I think the intent is not to use the manufacturer's stated trailer tongue weight or empty trailer tongue weight, but the actual trailer tongue weight when loaded, when making these calculations.

What I learned:
The weight of all the gear added behind the rear axle of the tow vehicle (cargo in the bed, the ball & hitch, the sway control) should be considered in addition to trailer tongue weight when choosing the correct spring bars for a weight distribution system.


The statement below is copied/pasted from E-HITCH.COM:
"If you want to use a weight distribution system, remember to include the weight of any gear you might load behind the rear axle of the tow vehicle. You should add the weight of this gear to your tongue weight to select a weight distribution system of the proper size."

[Tincampers]

Glad that is cleared up. I've been searching for that same answer.

[A W Warn]

I created an Excel spread sheet to help me quickly analyze the results when weighing at the Cat Scales. I have adapted it for PP & HA users (correctly I hope). For some reason the document will not attach to this post.

I have added some instructions to make it easier for others to understand how to use it. It works like this:

1. First section - enter data in blank spaces = the specified maximum load limits for your tow vehicle, trailer, and your hitching equipment.
2. Second section - enter data in blank spaces = your Cat Scale results
3. Third section - results are automatically calculated by the spreadsheet.

If anyone would like to try it, PM me and I will be glad to email it to you. Or, can someone (moderator?) tell me if I can attach Excel to a post so I can share it.

[Al and Missy]

From the truck's perspective, it seems to me that the difference between the weight measured on the tow vehicle's axles without any components of the WD installed and the same weight with the trailer connected and WD engaged is the tongue weight. If weight is placed on the hitch it should be measurable at the tow vehicle axles. At least with an Equalizer hitch it seems that the torque applied by the WD bars serves to reduce the torque generated by the tongue weight and thus the effect of the weight applied to the truck receiver.

That said, I think the static tongue weight of the trailer as measured with a scale is the number to use when selecting a hitch head because that is the weight applied to the ball on the head.

Al

[A W Warn]

For my 1,000th post. I am attaching the spreadsheet I created to analyze results of weighing my trailer using Cat Scales.
My intent is to measure the load on every component of the tow vehicle, hitch, sway control, and trailer which has a load rating. And, to measure the ratio of trailer to trailer tongue load. I hope it is helpful.

If you find something that is incorrect, or have suggestions for improvement, I am always open to change.

[ghaynes755]

Alan suggested changes would be in Section 1 you could automate data points such as the Max Payload by using the weights from the third weigh against the GVWR. There are a few such calks that could be automated. Similar spreadsheet to the one I have published several times. Only weights I don't have are for all of the ProPride pieces. But the results get to the same place. Mine was based on the PP instructions from awhile ago.

[Ron Gratz]

Alan,

It seems to me there is a fundamental disconnect between the definitions of "tongue weight" summarized in your Post #1 and the definition of "tongue weight" embodied in your spreadsheet.

I find nothing in any of the sources for "tongue weight" cited in your first post which states or implies that "tongue weight" is the downward force acting on the hitch when weight distribution is applied.
To the contrary, I believe every one of those sources intends for the "tongue weight" to be measured free from any effects of WD.

The values for "trailer tongue weight" presented cells F71, F73, and F85 are based on the value in cell F67 which is calculated as (G45+I45)-(G49+I49).
The sum of G45+I45 is the TV's GVW with WD tensioned.
The sum of G49+I49 is the GVW of TV only.
In essence, you have deducted the load transferred to the TT's axle(s) from the tongue weight.

Therefore, it seems to me that your spreadsheet's definition of "tongue weight", which does include the effect of WD, is in conflict with the results of your research presented in Post #1.

IMO, the term "tongue weight" should be defined as vertical load, resulting from weight of trailer and cargo, as applied to the ball.
I agree with including the weight of any accessory which essentially moves as part of the trailer -- such as a friction sway bar.
I would argue that only 50% of the weight of WD bars should be included as tongue weight since the front part of a WD bar moves as part of the TV while the rear part moves with the TT.
For the HA/PP hitches, I would consider the weight of the drawbar and lower (front) unit as part of the TV, the weight of the upper (rear) unit and strut/yoke assembly as part of the TT, and would distribute the weight of the linkage bars and WD bars equally between TV and TT. For simplicity, I would allot 50% of the total weight to the TV and 50% to the TT.

I respect and applaud all of the effort you are putting into defining these important terms. My remarks are offered in an effort to promote understanding and agreement and are not meant as a negative criticism of your work.

Ron

[A W Warn]

Ron & Gary,

I appreciate the input! Critique is good.

I appreciate you pointing out the formula error. I'll look at it in more detail. In my working days I dealt with spreadsheets like this on a daily basis. Guess I've gotten a little rusty, starting my 5th year of retirement.

The vehicle industry clearly defines trailer tongue weight, I tried to represent that. Though, I wanted my spreadsheet to show the load rating and/or the actual weight of each component. Since there seems to always be contention where some loads should or should not be applied, I thought I would not apply portions of the hitch or sway to one category or another. The user can shift those loads/weights to suit themselves.

Thanks again!

[A W Warn]

Originally Posted by Ron Gratz

The values for "trailer tongue weight" presented cells F71, F73, and F85 are based on the value in cell F67 which is calculated as (G45+I45)-(G49+I49).

Ron

Error corrected.
Thanks Ron

Towing weight calculator and result analyzer-rev1.xls

[ghaynes755]

And a big thanks to Ron as I believe that my spreadsheet and many other calculations are based on his original post. Really does help dial in a WD system.

[A W Warn]

Originally Posted by ghaynes755

And a big thanks to Ron as I believe that my spreadsheet and many other calculations are based on his original post. Really does help dial in a WD system.

Gary,

I got back from a week of camping this evening, so I am just now reading your post. I found a spreadsheet you posted in another thread. Is this the one you are referring to? (http://www.airforums.com/forums/f464...ml#post1460987). I wanted to see if I could learn something from your spreadsheet. I found it works specifically for your truck, but not for everyone without some modification.

I was trying to create a spreadsheet that anyone could use, even someone that knows nothing about Excel formulas/spreadsheets, a spreadsheet that anyone can read the instructions, simply fill in the blanks, get the result, without doing the math/calculations. I want the spreadsheet to work for any tow vehicle, for any hitch, for any sway control, and for any trailer.

[A W Warn]

I'm a little disappointed that there have been so few comments on the calculator spreadsheet! Two weeks and no one has tried it?
I was hoping to get some feed back, good or bad.

I'll move on to another subject: Tow Vehicle Weight Ratings.

Generally, a tow vehicle will not carry its maximum payload while towing its maximum trailer load without exceeding some other limit. I created a chart to demonstrate this so that I would know how I could load my truck and trailer.

The chart shows the load limits of my tow vehicle and the varying loads upon it as payload and trailer weights change.

The chart highlights the three different trailers that I tow, at their GVRW.

The chart demonstrates the point at which payload has to be decreased as a heavier trailer is towed.

Hope you find this helpful.
varying towing loads.pdf

add edit:
After I posted I noticed some of the color coding is incorrect. Too late to do over and re-attach it. The numbers are correct.

[Ron Gratz]

Originally Posted by A W Warn

The chart shows the load limits of my tow vehicle and the varying loads upon it as payload and trailer weights change.

Alan, your chart is a novel approach at demonstrating the relationship between trailer weight and available payload for given values of GCWR and TV Curb Weight.
Expressed as an equation, that relationship is:
Available Payload = GCWR - TV Curb Weight - TT GVW

Your chart also shows the relationship among TT weight, tongue weight percentage, and tongue weight for six values of TW% from 10% to 15%.
And, via color coding, the chart shows those combinations of TT weight and TW% which produce tongue weight in excess on a given value (1200#).

Although not stated, the "Available Payload" must include the vertical load which the TT imposes on the TV.
I think it would be informative to show how much payload capacity remains after accounting for the vertical loading.
I also think the tongue weight values currently displayed in the right six columns are not a particularly good use of space since they are easily calculated by a simple multiplication of TT weight times TW%.

I would recommend that, instead of tongue weight, you use the right six columns to display "Remaining Payload" which would be defined as your current "Available Payload" minus vertical load imposed by the TT. The vertical load could be set equal to tongue weight, or it could be some percentage of tongue weight to account for the effect of WDH load transfer to the TT's axles.

For example: using the 9800# weight of your Excella and assuming vertical imposed load is equal to tongue weight, you could calculate and display "Remaining Payload" values, instead of tongue weights, for the six TW%s.
At 9800# the six values of "Remaining Payload" would be 620, 522, 424, 326, 228, and 130# for TW%s of 10, 11, 12, 13, 14, and 15%.
The relationship is:
Remaining Payload = TV GVWR - Curb Weight - Vertical Imposed Load

In addition to displaying the Remaining Payload values in the six right columns, you also could use color coding to indicate those combinations for which the calculated tongue weight exceeds a given value.

Now, I expect that you and I will be scolded for obsessing too much about weight and ratings -- but, hey, it's your thread.

Ron

[A W Warn]

Ron,

As always, I appreciate your thoughts. Thank you!

My original purpose was not to evaluate the results of one specific weighing or one specific tow vehicle, but to evaluate a varying range of weights and different vehicles.

I created this spreadsheet last year when I was considering purchasing my next tow vehicle (obsessing may be correct). I was trying to understand the possibilities of different vehicles. At the time I did these evaluations it served its purpose. This spreadsheet helped me understand which tow vehicle would work for me. The document you see is the results of one of those evaluations, the one with my truck specifications plugged in.

The purpose for the multiple columns showing the varying hitch load percentages: To demonstrate how shifting cargo within the trailer allows one to tow a heavy trailer while staying within that 10%-15% load range, and specifically for me to understand when shifting of cargo would be necessary with each vehicle being evaluated. It would also show me when it would be beneficial to remove cargo from the tow vehicle and relocate it into the trailer. Also the columns demonstrate the point the hitch load would exceed the manufacturer's hitch load limits. They also demonstrate the load points where weight distribution is required due to varying load.

What you see is just a portion of that spreadsheet. I printed it as a pdf document to share it, hoping it would be used as a tool to help someone understand that even if a vehicle is rated for a maximum load, it will not tow that load and carry the maximum payload at the same time.