Airstream tongue weight is way too high vs the spec? True or False?

[foobar]

Short answer is to the question of whether or not Airstream underestimates their tongue weight ... I'll state up front that this assertion is mostly "false".

Note: I posted some of this in another thread yesterday that was mostly devoted to a different topic. Subsequently, I figured this deserves it's own dedicated thread.

Now to begin the topic at hand ...

Since joining the airforums back in Feb, I have read literally hundreds of postings reminding newbies that you can expect tongue weights way above the factory spec when you receive your new trailer.

This isn't really true, I found out. This knowledge came as a serendipitous discovery when I decided to weigh my "factory fresh" 2022 Globetrotter 27 FB Twin on the way home from the dealer.

Experimental conditions (yeah, I'm an engineer, so sue me ):

The Cayenne S was empty except for the driver and passenger up front and a full tank of fuel.

The Airstream had full propane bottles and a couple of Interstate Flooded Lead Acid batteries up front, but was otherwise empty (except for whatever Airstream provided at the time of purchase). Note: We drained all of the Airstream tanks before we left the dealer lot.

CAT Scale results:

Pass number 1 on the CAT Scale (trailer hooked up, with tension on WD bars):

3060 lbs TV Front Axle Load
3260 lbs TV Rear Axle Load
5880 lbs TT Axles Load

Pass number 2 on the CAT scale (trailer hooked up, no tension on WD bars)

2460 lbs TV Front Axle Load
4080 lbs TV Rear Axle Load
5660 lbs TT Axles Load

Pass number 3 (tow vehicle only, full tank, 1 driver, 1 passenger up front)

2860 lbs TV Front Axle Load
2620 lbs TV Rear Axle Load

That's the end of the measurements. Now for the results of some spreadsheet calculations:

5480 lbs Tow Vehicle (TV) weight

12200 lbs Gross Combined Weight (weight of trailer and tow vehicle)

6720 lbs Travel Trailer (TT) Weight = Gross Combined Weight - TV Weight

1060 lbs Travel Trailer Tongue Weight***

*** Note: the TT tongue weight measurement includes hitch weight @ 95lbs + friction anti-sway (2*14.6lbs) + Tekonsha Brake Controller @ 5.5lbs)

Now, let's calculate the Tongue Load Transferred to TT Axles when WD is active:
220 lbs transferred to TV axles when WD System is Activated
840 lbs Tongue Load transferred to TV axles

5480 lbs TV weight

12200 lbs Gross Combined Weight

6720 lbs TT Weight = Gross Combined Weight - TV Weight

1060 Tongue Weight (includes hitch weight @ 95lbs + friction anti-sway (2*14.6lbs) + Tekonsha Brake Controller @ 5.5lbs)

Now, let's calculate the Tongue Load Transferred to TT Axles when WD is active:
220 lbs transferred to TV axles when WD System is Activated
840 lbs Tongue Load transferred to TV axles

So, that's the results of the CAT scale measurements and some simple calculations to derive some other values that are of critical importance.

So now, let's get to the main topic of this thread: Does Airstream publish optimistic values for their trailer tongue spec?

The gospel truth here on the forum is that Airstream spec's for tongue weight are grossly optimistic.

Let's dig into that a little bit.

As stated by Airstream:
Tongue weight as delivered from the factory should include the weight of two full tanks of propane and two flooded lead acid batteries.

For my trailer (2022 Globetrotter 27 FB Twin), the spec for tongue weight is 875lbs.

The measured tongue weight from the CAT scales yields a value of 1060 lbs.

So, Airstream is wrong? Not entirely true ...

The spec from airstream doesn't include the weight of anything "the customer will add to the tongue".

In my case, I added:
94.5lbs for the Eax-lift Elite 1000 WD hitch
29.2lbs for two Husky friction anti-sway bars (14.6 lbs each)
5.5lbs for the Tekonsha electronic brake controller
------
129.2 lbs is what I added to the trailer tongue

So, 875 + 129.2 lbs = 1004.2lbs

Hmm, 1004.2lbs still doesn't add up to the 1060lbs that I measured. So, what am I missing?

What if Airstream doesn't really account for weight of the propane in the bottles and weighs the tongue with empty bottles?

The reason why I ask this question is that I managed to inspect my trailer right after Airstream delivered it to the dealer (i.e. before the dealer had a chance to do anything to the trailer) and I noticed that the propane tanks were empty at that time. However, when I took possession of the trailer, the dealer had filled both bottles of propane.

So, how much does the propane inside two 30lb propane bottles weigh? No, it's not a trick question ... the bottles cannot be completely filled with liquid. The built in OPD (Overfill Prevention Device) ensures that some space is left at the top of the tanks for propane vapor to form. Trust me, you don't ever want to have liquid propane make it's way into any downstream devices such as ovens, grills, heaters, etc unless you like to explode :-).

So, what is the total weight of propane in two 30lb propane bottles? The answer is 55lbs.

So, if I add up the following:
875lbs for Airstream factory spec for the tongue weight
94.5lbs for the Eax-lift Elite 1000 WD hitch
29.2lbs for two Husky friction anti-sway bars (14.6 lbs each)
5.5lbs for the Tekonsha electronic brake controller
55.0lbs for propane
--------
1059.2lbs is the grand total if you are estimating the eventual tongue weight before you take possession of your new trailer.

Now, let's refresh our memories as to what was my measured tongue weight for an "as delivered from the factory Airstream", but with two full tanks of propane instead of empty propane tanks? You already know the answer ... it was 1060lbs.

1059.2lbs is the estimated pre-delivery tongue weight and 1060lbs is the actual measure tongue weight as delivered from the factory. I would say these two values are pretty much equal

So, the Airstream factory spec for the tongue weight is actually, well ... mostly correct ... if you also add 55lbs to account for the propane that Airstream said was included in the trailer spec (but clearly was not in point of fact).

Conclusion: If you want to know the tongue weight for the trailer you want to buy, you will need to take the Airstream factory spec, add 55lbs for propane in two 30lb bottles (or add 77lbs for two 40lb propane tanks) along with adding whatever additional weight you will tack onto the tongue yourself for the WD hitch and any brake controllers, etc. This will be accurate within less than a pound or so of total rounding error.

Side note: yes, the "full" weight of the WD hitch is considered to be part of the tongue weight. Arguments that the stinger is actually attached to the tow vehicle and should be accounted for as part of the tow vehicle weight are really moot. So don't buy some god awfully heavy WD hitch and then try and complain about Airstream delivering trailers with tongue weights way above spec

I hope this helps any prospective future Airstream buyers and I hope this helps clear up the incorrect "common knowledge that Airstream tongue weight specs are grossly underestimating the actual tongue weight".

[mojo]

Believe what you want but the Cat scales will give you an approximate weight since they are designed to handle a lot more tonnage than an Airstream. You need a Sherline scale to get an accurate weight on your tongue weight. And you need to place it under the ball coupler, not the jack post because there will be a substantial difference otherwise. And yes there is a big difference between published dry weight and fully loaded trailer ready for travel.

[Aluminium Falcon]

Your analysis is thorough, insightful and convincing. Thanks for really delving into the issue!

[foobar]

Originally Posted by mojo

Believe what you want but the Cat scales will give you an approximate weight since they are designed to handle a lot more tonnage than an Airstream. You need a Sherline scale to get an accurate weight on your tongue weight. And you need to place it under the ball coupler, not the jack post because there will be a substantial difference otherwise. And yes there is a big difference between published dry weight and fully loaded trailer ready for travel.

I asked the CAT scale operator what the accuracy level is for different weight ranges. Here is what I received:

CAT Scale (Digital, made by Fairbanks Scales)
Capacity: 200,000 pounds,
Division: 20 pounds Accuracy: HB 44, Class III L
±20 lb (2,500 lb) (i.e. 0.8% error)
±20 lb (10,000 lb) (i.e. 0.2% error)
±40 lb (20,000 lb) (i.e. 0.2% error)

The scales are calibrated starting with 2000lbs.

My vehicle weighs 5500 lbs with two passengers and 12,000 lbs or so with the trailer included.

With all due respect, your answer is another one of the internet myth's that isn't true. No offense...

Forgot to mention that my Sherline scale read 1055lbs on the ball location (not the tongue jack).

[Dennis C]

That’s quite an analysis!

I think that the issue that causes so much discussion on the forums is that people make decisions based on the numbers published in the brochure, but those numbers don’t reflect reality. Once the propane tanks are filled and the trailer is loaded for camping, the tongue weight is generally much higher than the number in the brochure. The average person isn’t going to put as much thought into this as you have done.

I weighed my Airstream’s tongue weight using my Sherline scale, and it’s roughly 21.8% higher than the number published in the brochure. I’ve done calculations similar to yours and I can get to a number that’s quite close to what the scale shows, just like you did.

I’m not accusing Airstream of low-balling the number. They don’t know how each individual will load their trailer. All they can do is provide the weight based on the criteria that they define. It can become problematic when people see that number in the brochure and assume it’s not going to change.

[foobar]

Originally Posted by Dennis C

That’s quite an analysis!

I think that the issue that causes so much discussion on the forums is that people make decisions based on the numbers published in the brochure, but those numbers don’t reflect reality. Once the propane tanks are filled and the trailer is loaded for camping, the tongue weight is generally much higher than the number in the brochure. The average person isn’t going to put as much thought into this as you have done.

I weighed my Airstream’s tongue weight using my Sherline scale, and it’s roughly 21.8% higher than the number published in the brochure. I’ve done calculations similar to yours and I can get to a number that’s quite close to what the scale shows, just like you did.

I’m not accusing Airstream of low-balling the number. They don’t know how each individual will load their trailer. All they can do is provide the weight based on the criteria that they define. It can become problematic when people see that number in the brochure and assume it’s not going to change.

Airstream can only control what they deliver from the factory. As you point out, the user is the dominant variable in the equation.

My hitch weighs 95 lbs. Some of the hitches are 2x that weight or higher from what I recall others mentioning. I'll pick on propride for a second. They weigh on the order of 195lbs. So if I was using one of those hitches, my tongue weight measurement would have been 1160 instead of 1060.

Toss a big lithium battery bank of 1200amp hours inside the front storage compartment in a front bed configuration and you've added another 300lbs or so to the tongue weight (I'm guessing here, so don't beat me up ... the actual bank weight would be about 425lbs, but some weight will be carried by the trailer axles).

[SilverWind]

I realized that Airstream's tongue weight estimates fluctuate wildly, especially with vintage models, so I purchased a Sherline LM 1000 Trailer Tongue Weight Scale-1000LB.

The $128 investment is modest compared to the time and money spent guessing tow vehicle and hitch system suitability. Take the scale to the dealer to get an accurate reading yourself before you purchase the trailer. Make sure you understand propane tank empty and full weights and whether the trailer batteries have been installed before making a final determination.

https://www.amazon.com/Sherline-LM-1.../dp/B007REJTGI

[foobar]

I always figured that whatever I added to the tongue myself (in terms of weight) was not included in the Airstream spec (since they would have not idea in advance what I would choose to hang off the A-Frame up front) and would have to be added to the Airstream tongue weight spec number.

So these measured tongue weight values are not a surprise to me.

The same thing will happen if someone buys an SOB trailer.

If your tow vehicle receiver tongue weight limit is 800lbs and the trailer spec from the manufacturer is also 800lbs, the bell that goes off in your head shouldn't be an angel chime , it should be an alarm bell .

Once you fill the propane bottles and toss a propride hitch on it in my example above (yeah, propride owners are going to be my whipping boy for this exercise ... no offense intended), they are going to be 30+% over their allowed tongue weight spec for the tow vehicle receiver.

[foobar]

Originally Posted by SilverWind

I realized that Airstream's tongue weight estimates fluctuate wildly, especially with vintage models, so I purchased a Sherline LM 1000 Trailer Tongue Weight Scale-1000LB.

The $128 investment is modest compared to the time and money spent guessing tow vehicle and hitch system suitability. Take the scale to the dealer to get an accurate reading yourself before you purchase the trailer. Make sure you understand propane tank empty and full weights and whether the trailer batteries have been installed before making a final determination.

https://www.amazon.com/Sherline-LM-1.../dp/B007REJTGI

You are on the money SilverWind ... and exactly right ... words worth living by ...

[hikingcamera]

Originally Posted by foobar

Short answer is to the question of whether or not Airstream underestimates their tongue weight ... I'll state up front that this assertion is mostly "false".

I think one thing you are missing in your analysis is the curb weight listed on the website versus the one listed on the tag on your trailer. Mine, with no factory add ons, was 78 lbs higher than is listed on the website/brochure. With addons like solar or awnings it could be higher. That would add to your tongue weight as listed on the website or in the brochure. In my case, Airstream was being optimistic about my curb weight (and I expected it because they listed the same curb weight for the 23 corner bed and 23 corner bunk bed, which obviously cannot be right). I have also seen folks with 2021 versions of my trailer (where the brochure listed 4700-some as the curb weight) have actual weights higher than my trailer. So the addons they got from the factory clearly added several hundred pounds. At 13.5% tongue weight (the approximate ratio for my trailer according to the brochure), that's 40 lbs right there. I imagine it could be higher in bigger trailers.

[mikeinca]

Originally Posted by foobar

Toss a big lithium battery bank of 1200amp hours inside the front storage compartment in a front bed configuration and you've added another 300lbs or so to the tongue weight (I'm guessing here, so don't beat me up ... the actual bank weight would be about 425lbs, but some weight will be carried by the trailer axles).

You're not far off about the weight of 1200Ah of lithium batteries although I dare say most folks don't put that big of a battery bank in their front storage compartment. I have 4x100Ah Battle Born batteries and a 3000w Victron inverter in the front storage of my 25' FBT GT and getting more battery capacity in there would be a pretty tight fit.

The lithium batteries are each about half the weight of the 2 lead acid batteries they replaced and are further back in the chassis so the weight difference on the tongue is no worse than a wash.

[Dennis C]

Originally Posted by foobar

Airstream can only control what they deliver from the factory. As you point out, the user is the dominant variable in the equation.

My hitch weighs 95 lbs. Some of the hitches are 2x that weight or higher from what I recall others mentioning. I'll pick on propride for a second. They weigh on the order of 195lbs. So if I was using one of those hitches, my tongue weight measurement would have been 1160 instead of 1060.

Toss a big lithium battery bank of 1200amp hours inside the front storage compartment in a front bed configuration and you've added another 300lbs or so to the tongue weight (I'm guessing here, so don't beat me up ... the actual bank weight would be about 425lbs, but some weight will be carried by the trailer axles).

My 21.8% number does not include my hitch. That number was calculated based on the weight directly at the coupler. My Blue Ox Sway Pro weighs 63.8 lbs.

The tongue weight discussion is one that has many variables. If the fresh water tank is full, then the weight goes up. If propane tanks are partially full, then the weight goes down. Batteries, solar panels, etc. all come into play.

[foobar]

Originally Posted by hikingcamera

I think one thing you are missing in your analysis is the curb weight listed on the website versus the one listed on the tag on your trailer. Mine, with no factory add ons, was 78 lbs higher than is listed on the website/brochure. With addons like solar or awnings it could be higher. That would add to your tongue weight as listed on the website or in the brochure. In my case, Airstream was being optimistic about my curb weight (and I expected it because they listed the same curb weight for the 23 corner bed and 23 corner bunk bed, which obviously cannot be right). I have also seen folks with 2021 versions of my trailer (where the brochure listed 4700-some as the curb weight) have actual weights higher than my trailer. So the addons they got from the factory clearly added several hundred pounds. At 13.5% tongue weight (the approximate ratio for my trailer according to the brochure), that's 40 lbs right there. I imagine it could be higher in bigger trailers.

Fair point hikingcamera... let me see ... I think I took a photo of the sticker on the side of the trailer when I went to inspect it before purchase.

Yup. I did take a photo. The curb weight on the sticker was 6613 lbs vs the Airstream spec of 6300lbs.

The spec is built around the front bed queen "I think" and the twin bed option will definitely be heavier. I also added the 2nd A/C option that would also add to the tongue weight as it is forward of the two axles.

So, perhaps the 55 lbs increase in tongue weight wasn't due to the weight of the propane, but to the twin bed configuration and to the 2nd a/c.

Given that my curb weight was higher than spec and I know some of that is due to the weight forward of the axles, it's more likely that those two items (twin beds and 2nd a/c) are the cause of the increased tongue weight versus the spec'ed tongue weight and the 55lb delta happening to match the weight of propane in two 30lb bottles could have been a coincidence.

Folks, I hope you read down this far ... I'll admit that I missed something in the initial analysis. Thank hikingcamera for pointing it out.

[foobar]

Originally Posted by Dennis C

My 21.8% number does not include my hitch. That number was calculated based on the weight directly at the coupler. My Blue Ox Sway Pro weighs 63.8 lbs.

The tongue weight discussion is one that has many variables. If the fresh water tank is full, then the weight goes up. If propane tanks are partially full, then the weight goes down. Batteries, solar panels, etc. all come into play.

True, the cargo loading and distribution all come into play when someone actually tries to use the trailer.

I was trying to tackle the question of the "at delivery" tongue weight vs Airstream spec, before too many end user variables come into the picture.

[WellSaid11]

Did you add your new axles on your new trailer into your calculations for tongue weight?

[Dennis C]

Originally Posted by foobar

True, the cargo loading and distribution all come into play when someone actually tries to use the trailer.

I was trying to tackle the question of the "at delivery" tongue weight vs Airstream spec, before too many end user variables come into the picture.

Got it. I think you’re onto something with the specs of each individual trailer. I know my trailer was quite a bit heavier than the number in the brochure when I took delivery.

[foobar]

Originally Posted by WellSaid11

Did you add your new axles on your new trailer into your calculations for tongue weight?

I measured the trailer right after picking up the trailer from the dealer. No modifications were made to the trailer and there was no gear of my own placed in the trailer.

The only loads I added were the Eaz-lift Elite 1000 WD hitch and the Tekonsha brake controller to the A-Frame up front.

[jcl]

X lbs added to the trailer only adds x lbs to the tongue weight if it is in fact located at the tongue. It is typically a % of x depending on where it is located between the trailer axle and the tongue. That can apply to batteries, propane, trailer options, etc.

Similarly, depending on the WD hitch, a WD hitch won’t necessarily add the full hitch weight to the tongue, as it can extend the tongue to trailer axle distance, thus providing more leverage to pick up the front of the trailer even before WD bars are tensioned.

Detailed analysis, but I wouldn’t use decimal places. I have always worked to a 20 lb accuracy on truck scales.

[OrangeCrush]

Foobar,
Nice bunch of data and congrats on your new Globetrotter. What's your GVWR and front/rear GAWR on that Cayenne S?

[foobar]

Originally Posted by jcl

X lbs added to the trailer only adds x lbs to the tongue weight if it is in fact located at the tongue. It is typically a % of x depending on where it is located between the trailer axle and the tongue. That can apply to batteries, propane, trailer options, etc.

Similarly, depending on the WD hitch, a WD hitch won’t necessarily add the full hitch weight to the tongue, as it can extend the tongue to trailer axle distance, thus providing more leverage to pick up the front of the trailer even before WD bars are tensioned.

Detailed analysis, but I wouldn’t use decimal places. I have always worked to a 20 lb accuracy on truck scales.

Hi jcl, I'm aware that location of the weight matters with respect to how much weight ends up on the ball vs the trailer axles, etc. In this analysis, I tried to keep things simple and not make everyone's heads spin by taking a free body analysis approach

However, when it comes to the WD hitch, it's a totally reasonable approximation to lump all of it onto the ball (e.g. tongue weight) as that first order approximation is pretty darn accurate. Anything within a couple of feet of the ball location will end up with most of the weight on the ball (like 90% or so) so this simplification was acceptable to me.