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Old 07-04-2013, 04:20 PM   #1
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Confused on tongue weight for my Safari

We tow our 25 Safari FB LS with a GMC 3500 Duramax. I know it's overkill but the truck is a leftover from when we were misguided into a 5th wheel instead of an Airstream! So, my truck weighs 8,200 lbs. and I'm using 1000# bars on an Equilizer hitch (which I got from the previous owner who towed with a Dodge SUV). The trailer weighs in at 5400#. My questions are, first, I seem to need very little tension on the spring bars to meet specs. The rear squats a bit but the front doesn't move up at all. ?? Second, I have 1,000 tongue weight. Why so much tongue weight? Is this unusual? What am I missing here? Sure need some advise.
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Old 07-04-2013, 04:33 PM   #2
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I can't offer up any specific advice for your extra heavy duty TV but I can tell you about my experience.

I am towing the exact same trailer as you. I have a Tundra which is a half ton. I used to tow a white box with an Equalizer hitch with the 750 lb bars. When hooked to the Tundra I had to crank it down a bit to get everything lined up and level. It towed fine but it did make some noise when backing and going slow.

I picked up the Airstream a few years ago and it came with the larger Equalizer with the 1K bars. After a few trips I had to re set it and found that everything looked pretty good with little pressure on the bars. Little at least when compared to how they were before. It rides nicely and the noise is almost gone. I was wary of sway but the set up is very good as far as controlling things in high winds, bumpy roads and lots of oncoming and passing traffic including those big semis.

My rear squats a bit and the front might be a tad higher but not much. If you are concerned, add a washer to the head and then check the numbers. I think you are OK the way you are.
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Old 07-04-2013, 04:34 PM   #3
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Your truck can take a lot of tongue weight without much change in ride height. My 2500 can take about 1200 lbs before I see any noticeable squat.

SUVs generally has suspensions more like cars to ensure a smooth ride and will squat in the rear and rise in the front.

I would expect your trailer to have a tongue weight around 600-700 lbs dry. If you are much over that, it's probably due to how your cargo is loaded. Moving heavy items to the rear would help a bit.

But with such a large truck, I wouldn't be so concerned. A WD hitch setup does require some tuning to get your front axle loaded. I set up an Equalizer hitch for my Suburban to deal with the 800 lb tongue weight of my trailer. Took three attempts.

You have to add spacers to the hitch head as well as adjust the height if the brackets that attach to the trailer frame. Be sure you bars are level and not unduly bowed when under load. 1000 lb bars should be quite sufficient for your trailer. In fact there are threads that imply that too stiff bars can actually damage your trailer.
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Old 07-04-2013, 06:18 PM   #4
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My suggestion would be to first; redistribute the contents within the AS so that the Tongue weight (TW) is 12% of the AS weight. Second; I would adjust the bars so that the weight of the AS is evenly distrubuted across the two AS axles. The weight distrubution across the truck axles will probably take care of itself if you've done the first two steps and haven't over loaded the truck bed. I'd stop at a road side scale and make sure that no truck axle is over loaded (greater than #3,500?). Those are the basics and will get you real close to where you want to be.
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Old 07-05-2013, 05:18 AM   #5
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That seems awfully light for a loaded 25 footer. When I had mine the empty weight wasquoted as 5400 , but loaded I think it was closer to 7000 pounds, with gross weight at 7300 . Memory might be faulty here. Your tongue weight might not be that far off if you are loaded up with full tanks, water and propane, and lots of camping gear. Jim
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Old 07-05-2013, 05:20 AM   #6
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One more thing, with the size of your truck, the tongue weight could be raised easily to 15 percent without problems. Just my opinion from my experiences. Jim
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Old 07-26-2013, 07:32 AM   #7
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First off, the 5400 number is the manufacturer's weight. After you have it loaded, weigh it. My '06 Safari 25 FB weighs 6280# and with a propride hitch, the tongue weight is 1050#. That's 16%...a little on the high side. However, the floor plan of the FB makes it nearly impossible to redistribute weight inside the TT.
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Old 07-26-2013, 09:34 AM   #8
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The factory literature weights must be based upon theory. The empty weights on recent door side labels are from crossing the scales coming off the production line per federal law.

The literature stated a 833 pound tongue weight on our 25FB, but the Sherline scale showed 1.150 pounds at the dealership including the installed accessories, full propane tanks and the Hensley hitch head. The GVW is 7,300 pounds so we have about 16% tongue weight which is a little heavy.
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Old 07-27-2013, 05:27 AM   #9
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Originally Posted by voremus View Post
We tow our 25 Safari FB LS with a GMC 3500 Duramax. I know it's overkill but the truck is a leftover from when we were misguided into a 5th wheel instead of an Airstream! So, my truck weighs 8,200 lbs. and I'm using 1000# bars on an Equilizer hitch (which I got from the previous owner who towed with a Dodge SUV). The trailer weighs in at 5400#. My questions are, first, I seem to need very little tension on the spring bars to meet specs. The rear squats a bit but the front doesn't move up at all. ?? Second, I have 1,000 tongue weight. Why so much tongue weight? Is this unusual? What am I missing here? Sure need some advise.
A WDH first job is to bring the tow vehicle steer axle weight back to what it was with no trailer connected. On the same day, three passes across a weight scale will give the necessary info and the leverage of the WD hitch adjusted.

1] Truck and trailer, WD not appled
2] Truck and trailer, WD applied
3] Truck solo

The steer axle weight value in #2 and #3 should be identical (or very, very close) once the hitch is properly adjusted.

WD hitches with integrated anti-sway work best with hitch leverage maximized.

Visual checks are okay for a rough-in of the hitch (fender height measurements), but weight scale values tell the story needed. Smal adjustments can make a big difference as felt from behind the wheel.

See online for the CAT Scale Locator.

.
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Old 07-27-2013, 07:09 AM   #10
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Regarding tongue weights, I'll cut/paste a comment I just made on another thread as the discussions are similar.


I have been reading various threads about tongue weight as this seems to be the limiting factor in many light pickups and SUV's. Some report much less tongue weight when weighed where the trailer connects to the receiver, rather that closer to the trailer axles at the trailer jack.

Some hitches such as Hensley/ProPride put the tow vehicle receiver connection even further away from the trailer axles, effectively reducing the tongue weight actually carried by the tow vehicle.

When weight distribution is applied, some tongue weight is shifted to the trailer axles.

So a scale measurement of the tongue weight may not be the same as the weight actually carried by the tow vehicle receiver. It depends on the position on the tongue where it is weighed, and weight distribution when hooked up.

That makes me skeptical about the accuracy of tongue weight scales, relative to what we really need to know.

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Old 07-27-2013, 07:51 AM   #11
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The GVW of a trailer is based upon the weight of a free standing trailer, not the connected weight to the tow vehicle. That weight is determined by weighing the axles and the tongue weight and adding them together. This can be illustrated by the concept of using five individual wheel pad scales under a tandem trailer with four tires and the jack stand. The total of the weight numbers on each wheel pad scale should not exceed the GVW of the trailer posted beside the door.

Using a weight distribution hitch does not change the downward vertical force vectors we associate with weight. The weight distribution hitch allows the tongue vector to be distributed across the front and rear axles of the tow vehicle and a portion to the axles of the trailer.

Using a 1,200 pound tongue weight (downward force vector) for an example, the theory is that 400 pounds of force would be transferred to each tow vehicle axle and 400 pounds would be transferred to the trailer axle(s). Just because we transferred 800 pounds of force to the tow vehicle, we can not add 800 pounds more stuff inside the trailer. The trailer frame is still seeing and supporting the total GVW that was present from before the attachment to the tow vehicle.

Thus the tongue weight scale is a useful tool to help determine the actual weight of the trailer and whether the load is balanced or needs to be redistributed fore and aft.
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Old 07-27-2013, 08:56 AM   #12
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Originally Posted by switz View Post
The factory literature weights must be based upon theory. The empty weights on recent door side labels are from crossing the scales coming off the production line per federal law.

The literature stated a 833 pound tongue weight on our 25FB, but the Sherline scale showed 1.150 pounds at the dealership including the installed accessories, full propane tanks and the Hensley hitch head. The GVW is 7,300 pounds so we have about 16% tongue weight which is a little heavy.
If you want the tongue weight carried by the truck receiver, you need to weigh it where the truck receiver attaches to the trailer; that is below the Hensley. If you weigh it below the trailer jack it will be heavier, as you moved the scale closer to the trailer axles.

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Old 07-27-2013, 01:28 PM   #13
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Originally Posted by Denis4x4 View Post
First off, the 5400 number is the manufacturer's weight. After you have it loaded, weigh it. My '06 Safari 25 FB weighs 6280# and with a propride hitch, the tongue weight is 1050#. That's 16%...a little on the high side. However, the floor plan of the FB makes it nearly impossible to redistribute weight inside the TT.
From everything I've read about it there are 2 definitions of tongue weight.

1 Is the weight the receiver has to carry to support the tongue without W/D which would include the weight of the hitch. Required to check for TV ratings/compatibility.

2 Is to determine the proper balance of the trailer, this tongue weight is said to not count the weight of the hitch.

With that definition you would take about 200lbs off the weight of your trailer and off your tongue weigh (for the weight of the ProPride), so 6080# trailer 850# tongue weight that's about 14%, this would put it into the 10-15% range.
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Old 07-28-2013, 06:32 AM   #14
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If you remove the weight of the hitch from the calculation but it is still installed, you will be understating the total rig load by that amount. That 200 pounds did not vaporize. That downward force vector for the hitch weight is still on the trailer at the joint of the two vehicles and decreases tow vehicle payload capacity and must be considered when looking at the receiver weight rating.

The minimum suggested tongue weight has been from 10% to 15%. However, if the tow vehicle can handle the load, a slightly higher tongue weight is not a deal breaker.

Not much conversation occurs about the impact of the rotational forces used by leverage to push some of the tongue weight to the front wheels of the tow vehicle. The welding points of the receiver are actually supporting two sets of force vectors, the downward vector associated with weight and the rotational vector associated with forcing weight forward.

On my 2012 Dodge, there were reported issues with the welding of the round receiver support to the frame. Since my tongue weight was 1,175 pounds and the factory hitch was only rated 1,200 pounds, I removed the factory receiver and installed a Curt receiver rated at 2,550 pounds and now have excess capacity that can absorb the rotational forces as well as the weight related forces.
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Old 07-28-2013, 07:42 AM   #15
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switz, I'm certainly no engineer but thought I understood this. When you put the Sherline scale under the trailer jack you get 1,175#. If you moved the Sherline back towards the trailer axles another two feet, it would show a heavier weight. If you moved the Sherline forward to where to Hensley attaches to the truck receiver, it would show a weight lighter than 1,175#, and that is the actual weight carried by the truck receiver (before weight distribution is applied).

When weight distribution is applied, some the weight on the is receiver moved to the truck and trailer axles. In other words, the "downward vector" is decreased as the "rotational vector" is increased.

Your description of tongue weight measurement puts many, perhaps most of us with 25' Airstreams over tow vehicle receiver capacity. Is that the situation we have?

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Old 07-28-2013, 10:41 AM   #16
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If you remove the weight of the hitch from the calculation but it is still installed, you will be understating the total rig load by that amount. That 200 pounds did not vaporize. That downward force vector for the hitch weight is still on the trailer at the joint of the two vehicles and decreases tow vehicle payload capacity and must be considered when looking at the receiver weight rating.
That's why I said there are 2 definitions and you must use the first one I said for receiver and TV ratings. (the one with the hitch weight) Maybe the weight of the hitch head or "stinger" should be added to it also.

The second definition without the hitch weight is only for trailer balance. I remember something like this was said to be the case on the ProPride or Hensley website (but I can't find it now) with an explanation that the hitch weight was part of the receiver/TV as far as trailer balance, trailer weight and trailer tongue weight was concerned (some with small trailers may have expressed concern over the trailer frame supporting the added weight or the GVWR of the trailer being used up for the hitch).

If this second definition is true for trailer balance, if a trailer with a 200lb hitch weighed 6200lbs with a tongue weight of 620lbs or 10% if you remove the weight for the hitch it would be a 6000lb trailer with 420lb tongue weight or only 7% tongue weight and should have weight moved to the front.
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Old 07-29-2013, 04:12 PM   #17
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The concept is based initially on using a disconnected tandem axle trailer on the CAT scales on one weighing segment with the jack stand supporting the front of the trailer on that same scale segment. The scales show a total weight.

We borrow a fork lift and move the trailer forward and put the jack stand on a separate scale segment and adjust the jack to make it level. The four trailer tires on one segment show a lower weight that when added to the shown jack stand weight should equal the first weighing number. That total weight should not change just because we are weighing two segments instead on one.

Now we take the fork lift and turn the trailer around and put each axle on it's own segment with the jack stand on the third segment and ensure that it is level. We now have each axles weight and the jack stand weight which should all add up to the first weight of all trailer contact points on one segment.

All during this exercise, a Hensley hitch head has remained permanently attached to the trailer. It is a part of the total weight of the trailer and that Hensley weight is concentrated over the jack stand.

I take the trailer elsewhere without changing anything in the trailer,park and unhitch the trailer. I put a supporting stand under the frame and retract the jack stand upwards and slip the Sherline scale under the jack stand round pad and extend the jack stand so I can remove the supporting stand from the frame. If the trailer is level, the Sherline scale should display the same weight that has been recorded for the jack stand in the prior two efforts.

Because the permanently mounted Hensley ball is in the trailer socket, there is not a stationary place on the Hensley to have a lift point as the Hensley can rotate because of the ball connection to the trailer.

I choose to use the jack stand weight as the reference weight to see if the trailer load is balanced. Thus if that weight increases, I know I have too much stuff forward of the centerline of the axles. If the weight decreases< I know there is too much stuff behind the center line of the axles.

For discussion convenience, I will set the jack stand weight at 1,200 pounds which is slightly more than what I actually have on my 2013 25FB International International when loaded camping ready.

The truck has the installed Hensley stinger weight as part of the truck's weight when crossing the scales without the trailer. We have the individual axle weights and the total

We now know the total weight of the trailer and the total weight of the truck and now connect them. Without doing any adjusting to the hitch, we place the rig on a single segment scale and the total shown should equal the weights of each vehicle added together.

Now we shift to a three segment scale and have the trailer axles on one segment, the truck rear axle on a segment and the truck front axle on a segment. Once again the total of the three weights should equal the total combination weight of truck and trailer.

However, now the three weights individually should be different because the jack stand weight was attached to the stinger of the truck and the truck rear axle weight has increased, the bed has sagged under the load, the front of the trailer is lower and because of the leverage, the front of the truck could be higher and have less weight on the front axle.

We now attach the leveling bars and crank until the the truck is sitting level. By the use of leverage from the leveling bars we have raised the rear end of the truck and the front of the trailer. Some of that lever force has sent part of the down force of the trailer weight forward to the truck front end and some rearwards to the trailer axles.

In theory, about a third of the jack stand weight would appear on each axle because the single support jack stand is not touching the ground but the weight is still suspended.

Now we cross the scales again. We should see an increase in weight on both the trailer axles and truck front axle and a reduction in the weight on the truck rear axle. The total weight is still the same, but the carrying points have shifted and we might see a third to the trailer and the two thirds allocated to the truck.
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Old 07-29-2013, 04:46 PM   #18
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Once you crank on the WD bars, you increase the weight on the trailer axles, but the total weight of the trailer remains the same. Therefor, the weight on the hitch must decrease the same amount that the trailer axles increased. There is an added moment (rotation/twist) that the hitch must absorb.

But I think the importance of maintaining around 10-15% of trailer weight on the tongue has more to do with stability. Analogous to an airplane where you place the center of gravity ahead of the center of pressure (lift), you want the CG of the towed trailer ahead of the axles.
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Old 07-29-2013, 05:21 PM   #19
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Second, I have 1,000 tongue weight. Why so much tongue weight? Is this unusual?
It appears that there are no scales of any sort at the Airstream factory. I guess they put a bunch of numbers in a hat and pull one out. I have seen different tongue weight numbers in difference places on their website, presumably both wrong.

I don't think they add in full propane tanks and the spare tire. Maybe they don't even include the batteries.

So some number around 1,000 lbs. is probably correct as others have reported similar weights.

As has been said, approximately 2/3 of the weight goes to the truck axles an 1/3 to the trailer axles. This is important when calculating payload for the truck. With your TV, you probably don't have much to worry about with payload, however.

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Old 07-29-2013, 07:02 PM   #20
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. . . Because the permanently mounted Hensley ball is in the trailer socket, there is not a stationary place on the Hensley to have a lift point as the Hensley can rotate because of the ball connection to the trailer.
As this thread is about trailer tongue weight, it would be nice to know what the tow vehicle receiver actually carries (before weight distribution is applied).

A forum member with a ProPride locked the stinger into the hitch head, snugged up the weight distribution jacks so it couldn't rotate, and placed the Sherline scale under the ProPride stinger to get the actual trailer tongue weight carried by his tow vehicle receiver. That would be different (heavier) if weighed farther back toward the trailer axles. Seems like that would work for Hensley as well.

Not sure if I'm up for buying a Sherline scale just to know this, but if I did, I would want to know what it actually is.

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