Equalizer Hitch: 25/27 FBQ Model Indents? :(

[Hermes]

A hitch is a suspension system absorbing (or not) the vertical movement of the TV relative to the trailer.

As with a regular suspension it can be stiff or soft and this is determined by the stiffness/flexibility of the WD bars which also have another role and that is to raise the backend of the TV to transfer weight to the front axel.

The weight transfer capacity of the hitch is limited by the degree of stiffness of the WD bars, the stiffer the WD bars the more weight you can transfer to the front TV axel if you crank up weight distribution. But this is not without cost, the more you crank up WD the more pressure you are placing on the trailer frame, which means that given that stiff WD bars don't flex much, it's the frame that flexes when the road surface raises the TV relative to the trailer. The impact of excessive trailer frame flex on the structure on the trailer's front end is now well documented.

If you have flexible WD bars you will be limiting your ability to transfer weight to the front axel (the bars will just bend/flex) but you will be limiting the pressure placed on the trailer frame and you limit the risk of excessive frame flex.

When driving with flexible WD bars, as the angle of the TV varies according to the road surface, the WD bars will flex and act as a suspension system buffering the vertical movements of the TV relative to the trailer. This contributes to damping purpoising.

If you drive "on the ball" (without WD) then there is no weight transfer to the front axel, no pessure on the trailer frame, no danger of excessive frame flex, and no damping of purpoising. The TV and the trailer become independent of one another with regards to the vertical movement of the rig. This is not unusual, there are many commercial trucks pulling heavy shop-trailers on the ball, in fact I don't remember seeing one with WD!

[WellSaid11]

Originally Posted by Hermes

A hitch is a suspension system absorbing (or not) the vertical movement of the TV relative to the trailer.

As with a regular suspension it can be stiff or soft and this is determined by the stiffness/flexibility of the WD bars which also have another role and that is to raise the backend of the TV to transfer weight to the front axel.

The weight transfer capacity of the hitch is limited by the degree of stiffness of the WD bars, the stiffer the WD bars the more weight you can transfer to the front TV axel if you crank up weight distribution. But this is not without cost, the more you crank up WD the more pressure you are placing on the trailer frame, which means that given that stiff WD bars don't flex much, it's the frame that flexes when the road surface raises the TV relative to the trailer. The impact of excessive trailer frame flex on the structure on the trailer's front end is now well documented.

If you have flexible WD bars you will be limiting your ability to transfer weight to the front axel (the bars will just bend/flex) but you will be limiting the pressure placed on the trailer frame and you limit the risk of excessive frame flex.

When driving with flexible WD bars, as the angle of the TV varies according to the road surface, the WD bars will flex and act as a suspension system buffering the vertical movements of the TV relative to the trailer. This contributes to damping purpoising.

If you drive "on the ball" (without WD) then there is no weight transfer to the front axel, no pessure on the trailer frame, no danger of excessive frame flex, and no damping of purpoising. The TV and the trailer become independent of one another with regards to the vertical movement of the rig. This is not unusual, there are many commercial trucks pulling heavy shop-trailers on the ball, in fact I don't remember seeing one with WD!

There is a middle ground.

Pulling on the ball with no WD/sway control hitch but with a “suspension” shank/hitch such as a Gen-Y or AirSafe.

[GOUSC]

There are some very good, thoughtful comments in this thread. Like others, I’ve had the front end separation issue and posted on it previously.

When Airstream first fixed my front end separation issue they told me that there should have been four ribs in the front that extended to the subfloor.
Of those 4, 2 of them did not extend to the subfloor. With the other two, only one of them was attached and the L bracket on the other one was broken.

In my opinion, this was faulty construction upfront by Airstream and I would have had the frame separation issue regardless of tow vehicle or hitch used.

Jackson Center told me they extended the other two ribs to the subfloor and put beefier L brackets on all four ribs and thru bolted them to the frame. This was repaired under warranty and I felt the issue was fixed.

After an airstream caravan to the upper peninsula of Michigan I noticed my dimples had returned and the exterior skin had started to rip.

I made an appointment with a third-party, Collin Hyde, to assess the issue and repair it. He found that the L brackets installed by Jackson Center we’re not through bolted through the frame they were just screwed into it. So they were bound to fail over time. And they did.

I think there are various ways to repair this by competent repairmen. Collin‘s method was to install a vertical steel plate, welded to the frame and extending upward across the front. He then attaches a thicker aluminum sheet across the front, on top of this steel plate, and has numerous buck rivets across the front to bind this together.

I had him add interior access to this front storage area so it can still be used and available.

I’ve always acknowledged I’m no engineer but I can hire one to fix a problem. I’m in the middle of a 2 month trip to Newfoundland and their roads are not known to be the smoothest. So far, Collin’s repair has worked flawlessly on this trip and a 5 week trip to Mission, TX. To date, around 10,000 miles and including I-20 thru Shreveport, LA and I-10 east of Houston. It has been put to the test.

My opinion is that Airstream has a design flaw with the front storage compartment accessed from the outside. Per Collin, they used to have this steel plate across the front but it was removed when they added the exterior storage compartment. I’ve found the interior storage access the be just as functional as the exterior access.

If Airstream is reading this, I would suggest they consider this as an option. I understand they refuse to add the steel plate back to the front line they used to. However; I believe the interior access would allow users to still have that area to be used and not having that big hole in the front would allow them to provide more strength in the front area.

After Collin’s repair, I have used Pteck’s mod to add my Honda 2000 on the tongue and it has worked great on this trip to date. Having access in the interior has added more flexibility than I had before.

I agree with some of the comments that something has to give when you add too much W/D but I don’t feel it is entirely user error when there is a bad design to start with. Education is key and that should start with Airstream and their dealers IMO.

Thru this process I know way too much than I need to know about this issue. I know ignorance is bliss but this shouldn’t have to be that complicated. For Airstream to put this solely on the owners with no education on their part is not the best way to do this.

[WellSaid11]

GOUSC-

I have the same setup with the Gen-Y and EQ hitch. No FB but also
no issues as well on dimples and frame separation.

[foobar]

Hermes stated "If you drive "on the ball" (without WD) then there is no weight transfer to the front axle, no pressure on the trailer frame, no danger of excessive frame flex, and no damping of porpoising. The TV and the trailer become independent of one another with regards to the vertical movement of the rig."

This isn't correct. Example: If the rear wheels of the tow vehicle hit a speed bump, the entire rear of the tow vehicle will bounce upwards. This vertical movement includes the trailer ball. The trailer frame connected to the ball will bounce upwards as well. This transient force can push the trailer frame into the shell. If the shell cannot withstand this dynamic (e.g. transient) force, it will deform.

The suspension characteristics of the tow vehicle definitely have an impact on the dynamic forces experienced by the travel trailer, independent of the use of a WD hitch or "towing on the ball". For tow vehicles with stiff suspensions that are not very compliant (e.g. flexible/soft-riding), the dynamic force transfer can be quite high.

[OrangeCrush]

Originally Posted by foobar

Hmm... I have an idea what is happening here. Dynamic forces are pushing the frame up into the airstream shell (or conversely, forces are pushing the shell down onto the frame. It's the same thing really) as the trailer is bouncing down the road.

These forces cause the shell to flex right above the frame (i.e. bend upwards temporarily). As these forces push up on the lower rim of the storage compartment above the frame, the storage compartment rim (and the shell) distorts upwards in that location, causing the dimples to appear in the corners of the storage compartment and the rivets above the A-frame beams to shear off. Once the dynamic forces are removed, the shell and the storage compartment return back to their original positions. The extent of the dynamic (e.g. temporary) movement isn't sufficient to exceed the elastic limit of the structural members in that area and cause permanent distortion of the shell or the storage compartment rim above the trailer A-frame beams.

However, the dimples or creases in the outer aluminum shell in the lower corners of the storage compartment are not able to return to their original condition.

Eventually, the frequent flexing during travel will result in "work hardening" of the structural elements in the shell in these areas and the structural elements in these locations will become brittle and crack.

The Airstream shell is clearly inadequately reinforced in this area above the trailer A-frame beams. The cure would require a more substantial aluminum beam inside the shell running from left to right across the bottom of the front storage compartment in order to eliminate the flexing due to dynamic motion.

The magnitude of the dynamic forces (and thus the extent of the deflection and resulting longer term damage) is a function of multiple variables such as the WD hitch topology (stiffness or lack of flex in the WD bars), the stiffness of the tow vehicle suspension, the weight distribution inside the Airstream (weight in the front and back of the trailer that can cause hobby-horsing or porpoising), etc, etc.

The shell could be made stiff enough to withstand these forces without flexing, but clearly the existing shell engineering isn't adequate. Likewise, trailer owners can do things to help limit the extent of the problem by not towing with vehicles with very stiff suspensions (i.e. high load capacity TV's that are loaded to a decent percentage of their max capacity), choosing WD hitches with bars that are not overrated for the amount of weight transfer that is needed (or have more flexible torsion bars by design), and pay careful attention to trailer loading up front and for the weight distribution in the trailer.

Let the flame wars begin (it's not possible to have "too much tow vehicle", I have driven a million miles with super stiff WD bars without any issue, etc, etc ).

Spot on in my opinion, and explained well. Thanks!

[Hermes]

Originally Posted by foobar

If the rear wheels of the tow vehicle hit a speed bump, the entire rear of the tow vehicle will bounce upwards. This vertical movement includes the trailer ball. The trailer frame connected to the ball will bounce upwards as well. This transient force can push the trailer frame into the shell. If the shell cannot withstand this dynamic (e.g. transient) force, it will deform.

The suspension characteristics of the tow vehicle definitely have an impact on the dynamic forces experienced by the travel trailer, independent of the use of a WD hitch or "towing on the ball". For tow vehicles with stiff suspensions that are not very compliant (e.g. flexible/soft-riding), the dynamic force transfer can be quite high.

You are right, my statement was focusing on the stress put on the frame from WD, but in addition there is the vertical movement of the ball, in particular rapid/violent movement as well as vibrations from the TV that are transferred to the frame. I added suspension air bags to my TV rear suspension to soften this out. Andy Thompson recommended 10-12 pounds of pressure, and he recommended the replacement of my front end OEM shocks with Bilsteins to further reduce this vertical movement (if the front is swinging up and down, then the WD bars are pressing down on the frame). Your example of hitting a speed bump is clearly a situation where a shock will be transferred to the frame.

[PC Conner]

Originally Posted by WellSaid11

There is a middle ground.

Pulling on the ball with no WD/sway control hitch but with a “suspension” shank/hitch such as a Gen-Y or AirSafe.

I bought the Gen-Y (as in picture). Found it to be much too heavy for convenient use (mounting and dismounting/storing; I always remove the hitch from the TV when not connected to the trailer. I have backed into too many things as it is). Returned it (with re-stock fee).

Does anyone have experience with either Gen-Y or AirSafe WITH the dimples/pimples/creases/separation?

If no one with Gen-Y/AirSafe had the problem, that would seem to be causal vs correlated.

[WellSaid11]

I would not want to take the Gen-Y off all the time either as it does weigh a ton.

My Ram is not a daily driver and other than towing trailers, runs to dump stuff and haul stuff from HD/Lowe’s/landscape yard, etc. it doesn’t get driven so I don’t care about taking the Gen-Y hitch off (and it is locked to the truck as well) - other than backing into stuff as you said. Rear camera so that’s not an issue really either though.

As for dimples, I have a 28’ RBQ and use an EQ WD/sway hitch with 1200 lb. bars with no issues after many thousand miles of towing. Again, no front compartment though. Setup was recommended by Gen-Y and EQ for my AS and TV. AS dealer also said it was good to go.

As others have mentioned, the Gen-Y with the EQ has no sway and no porpoising at all. The Gen-Y is legit, and I have towed on the ball with it alone and it was remarkably free if sway or any other issues.

YMMV.

[pteck]

The Gen-Y/AirSafe's are oxymoron's.

Going back to first principles for stability on bumper pulls, it's incredibly important to keep the ball as close and tight to the rear axle as possibly to minimize overhang and leverage. Meaning as close and tight to the rear bumper. In this geometry, minimal WD and sway control are required to provide stability against overhung loads.

Yet a Gen-Y/AirSafe by design can add almost another 6-12" to the overhang. Exacerbating a fundamental parameter, now requiring more WD tension to return stability.

To expand on this more, we know that wheelbase is an asset to stability. It's not really just wheelbase, but wheelbase to rear overhang ratio. Most trucks have close to a 2:1 ratio. Adding 12" to the rear overhang is effectively almost equivalent to reducing 24" from wheelbase in regards to stability.

It's a fools errand to use these tools because marketing is preying on false intuition.

[dznf0g]

Originally Posted by pteck

The Gen-Y/AirSafe's are oxymoron's.

Going back to first principles for stability on bumper pulls, it's incredibly important to keep the ball as close and tight to the rear axle as possibly to minimize overhang and leverage. Meaning as close and tight to the rear bumper. In this geometry, minimal WD and sway control are required to provide stability against overhung loads.

Yet a Gen-Y/AirSafe by design can add almost another 6-12" to the overhang. Exacerbating a fundamental parameter, now requiring more WD tension to return stability.

To expand on this more, we know that wheelbase is an asset to stability. It's not really just wheelbase, but wheelbase to rear overhang ratio. Most trucks have close to a 2:1 ratio. Adding 12" to the rear overhang is effectively almost equivalent to reducing 24" from wheelbase in regards to stability.

It's a fools errand to use these tools because marketing is preying on false intuition.

Agreed, except your ratio is off for the most common TVs. My truck is a double cab regular bed and the overhang is 31% of the wheelbase. A crew cab, short bed will be the same. Crew cab, regular bed will be less than 31%. This is for GMs.

Non-the-less these "shock" drawbars don't help the situation relative to WD issues with Airstreams.

[WellSaid11]

Originally Posted by pteck

The Gen-Y/AirSafe's are oxymoron's.

Going back to first principles for stability on bumper pulls, it's incredibly important to keep the ball as close and tight to the rear axle as possibly to minimize overhang and leverage. Meaning as close and tight to the rear bumper. In this geometry, minimal WD and sway control are required to provide stability against overhung loads.

Yet a Gen-Y/AirSafe by design can add almost another 6-12" to the overhang. Exacerbating a fundamental parameter, now requiring more WD tension to return stability.

To expand on this more, we know that wheelbase is an asset to stability. It's not really just wheelbase, but wheelbase to rear overhang ratio. Most trucks have close to a 2:1 ratio. Adding 12" to the rear overhang is effectively almost equivalent to reducing 24" from wheelbase in regards to stability.

It's a fools errand to use these tools because marketing is preying on false intuition.

You are right, it doesn’t work and I am going throw it out.

When I tow on the ball alone it is absolutely no different that with the Gen-Y. No difference at all. None. Zero.

You are so right! After I towed with it on just the ball and then with the EQ, and all other combos as well, I then realized it was a big scam and despite a money back guarantee I decided to keep it anyway.

So now it lays on the garage floor on a bed of unneeded 100 dollar bills that I had laying around that were just going to be thrown in the fireplace anyway.

A testament to the “fool’s errand” of the Gen-Y, and to being lectured to by someone that actually wrote “oxymoron’s”. Outstanding irony.

Good ‘ol AS Forums - the land of the uninformed and self-righteous product experts that have never owned or used a product. However, their high school physics textbook says it isn’t needed so that’s the end of the issue. Somewhere a YT video is being thrown together quickly with wooden fulcrums and hand drawn diagrams……

Right.

[pteck]

Originally Posted by dznf0g

Agreed, except your ratio is off for the most common TVs. My truck is a double cab regular bed and the overhang is 31% of the wheelbase. A crew cab, short bed will be the same. Crew cab, regular bed will be less than 31%. This is for GMs.

Non-the-less these "shock" drawbars don't help the situation relative to WD issues with Airstreams.

3:1. So 12" added to the rear overhang can be similar to driving a vehicle with a 36" shorter wheelbase.

It's no wonder why even HD trucks can sway.

And why some believe they need such long wheelbases and HD trucks. And get defensive, or worse offensive, about their setups and how nothing but an HD truck will do.

[rufusd7]

Originally Posted by OrangeCrush

I understand your theory that stiffer bars are less compliant and can result in an increase in frame flex while TV/trailer are in motion or undulating as you put it. The data you provide shows stiffer bars are less compliant. There is no data that shows a less compliant bar is causing an increase in frame flex at a level that could cause the front end separation issue. Without this data your theory is still just that. As I said before, until someone instruments a unit and proves a hypothesis we are all just guessing.

In light of your latest hypothesis: What do you recommend for instrumentation? Would an MPU-6050 + RPi be sufficient? What would we need for the recording sample rate? Would 1 be enough? Where would I attach it/them?

This setup would be cheap and easy to implement.

[PC Conner]

THX WellSaid11. I hope to see a reply from someone with a FB model. Since the design of the RB avoids the issue.
While I don't think the Gen-Y is a fool's errand or belongs to an oxymoron, I don't like the weight, as mentioned, and the extra length it adds to the Trailer + TV. But, I prefer both the weight and length to frame separation.
I am not as concerned about the theoretical physics as I am about a fix to this significant problem. Perhaps the on-the-ball only is a good enough configuration and is what AS designed.

[Jeff7176]

I’m not super smart so most of what is now being discussed is passing well above my head. But, as someone who owns a FBQ model, I want to, again, add my experience.

Our 2018 25 FBQ has no front storage hatch. I pull my trailer with a 2019 F250 using a ProPride hitch. All in all, it is likely overkill, but we move at least 300 miles each week and I like the stability of my setup.

We have about 37K miles on our setup as of today, and have no signs of front end separation, dimples, divots, creases, cracks, etc. I don’t crank down (or up in my case) on the WD jacks, but do ensure the bars are firmed up before setting off. In light of this thread (and the few others) I have gone over the front of my trailer with as fine a tooth comb as I can and see no loose or missing rivets, or weird gaps, or other concerning types of things.

I just took the dog for a walk around the campground and saw two other Airstream trailers. One is a 27 or 28 (it appears to be a late 2000’s and up model) and the other is either a 25 or 26 (probably a late 90’s or early 2000’s model). Both have front storage hatches and both have very evident dimples at the bottom corners of the hatch…visible from 30 or so feet away.

In my opinion, the hatch is a major contributor to this issue. I don’t doubt that any Airstream could develop this kind of issue over time, but the models with the front storage hatch appear to have an inherent structural weakness. And as many of you have explained, there are significant forces that area of the trailer experiences. Seems like having a structure that reduces the support there is probably not a great design.

[WellSaid11]

Originally Posted by pteck

3:1. So 12" added to the rear overhang can be similar to driving a vehicle with a 36" shorter wheelbase.

It's no wonder why even HD trucks can sway.

And why some believe they need such long wheelbases and HD trucks. And get defensive, or worse offensive, about their setups and how nothing but an HD truck will do.

Or wonder why some HD trucks have no sway at all (even though trucks by themselves do not “sway” as it was stated)? I guess coming from someone that likely has never driven an HD truck, let alone owned one, or driven this particular configuration of set up, the academic exercises you are going through are somehow relevant?

No, they aren’t.

Funny that you say someone would get “defensive” about their setup. “Defending” a set up that works from someone that attacks it out of nowhere when they obviously have no experience with the set up but still are trying to discredit it?

Envy? Ignorance? Boredom? Bitterness? All of the above?

Time to dig back into the high school physics book while the rest of us tow - sway and dimple free.

[pteck]

Originally Posted by WellSaid11

Or wonder why some HD trucks have no sway at all (even though trucks by themselves do not “sway” as it was stated)? I guess coming from someone that likely has never driven an HD truck, let alone owned one, or driven this particular configuration of set up, the academic exercises you are going through are somehow relevant?

No, they aren’t.

Funny that you say someone would get “defensive” about their setup. “Defending” a set up that works from someone that attacks it out of nowhere when they obviously have no experience with the set up but still are trying to discredit it?

Envy? Ignorance? Boredom? Bitterness? All of the above?

Time to dig back into the high school physics book while the rest of us tow - sway and dimple free.

Sorry you're taking it this way. I could care less about your setup and was commenting in general. HD trucks have their purpose. But there is a slippery slope of configuration and setup, that leads to indents and bandaids. Ideas promoted by anecdotes and false intuition. Because it's easy to buy into the paradigm of more is better. Which the market is all too happy to cater to.

HD truck > bigger tension bars > more WD tension > hitch bandaids that further create bad geometries necessitating possibly even more of all the above.

Ever wonder why Andy and CanAM are able to do more with less? Follow first principles. Not saying anyone has to use less, but those same principles apply to big trucks and can make for better towing setups that are also more gentle on the Airstream.

You don't have to worry about me. I can well afford any HD truck I like, and that I choose to tow with an even more expensive SUV, but I guess is not here or there. I'll stick with the books, because engineering aircraft isn't as forgiving as dimples.

[pteck]

There's also false intuition here that it's the front storage models that are weak. That's not really true.

They are probably more rigid due to the frame of the door. This creates less opportunity to accommodate flex and will reveal more evidence of it due to concentration of stress risers in the form of dimples and cracks around the frame of the door.

The problem is ultimately the same. Everything flexes. It's the degree of. Due to the forces manifested on the Airstream structure.

An HD truck can apply much greater forces due to it's stronger and longer structure.

Solution is to keep the ball as close and tight to the bumper as possible. It can be hard as modern trucks have such tall bed heights necessitating more clearance to the tongue jack. It is a critical dimension.

Use less WD bar and tension (and probably not even 50% FALR as that creates huge tongue forces when considering how long HD trucks are). Rely on the inherent mass and stability of the truck.

[WellSaid11]

Originally Posted by pteck

Sorry you're taking it this way.

Not taking it in any specific "way" but rather am responding to what you wrote.

Originally Posted by pteck

I could care less about your setup and was commenting in general.

No, you were specifically responding. Actually, it is "I couldn't care less" because as you wrote it you could still care. Just saying, for future reference....just in case.

Originally Posted by pteck

HD trucks have their purpose. But there is a slippery slope of configuration and setup, that leads to indents and bandaids. Ideas promoted by anecdotes and false intuition. Because it's easy to buy into the paradigm of more is better. Which the market is all too happy to cater to.

Right, because having the right setup is still bad because you actually have several components that work. But, having more than you think someone needs is just plain bad - even if it works. That's some serious logic to be sure.

Also amazing that someone that clearly has the same setup doesn't realize how the Gen-Y shank attaches to the EQ hitch. Pretty much the same distance from the receiver as with the EQ shank and the Gen-Y shank (which replaces the EQ shank), but of course you already know this having the exact same setup and must have just misspoke about all of it thinking that somehow another 12" or more is added to the setup (on a short bed HD no less, yet another huge hole in your continued speculation as it appears you assume all HD trucks have a bed that is 20' long). Yep, that must be it.

Originally Posted by pteck

HD truck > bigger tension bars > more WD tension > hitch bandaids that further create bad geometries necessitating possibly even more of all the above.

You really have no idea about what you are talking about, do you? For an EQ (like most hitches), the size of the bars (and hence potential tension) is based initially upon the GVWR of the TRAILER and the tongue weight, whereas 1/3 of actual rear payload for the TV comes into the calculation after that. That 1/3 number can and is all over the place for all kinds of TVs and not dependent on HD, 1500, SUV as those all can have wildly different rated and actual payloads.

Ignoring reality and under your logic, I would use 1500 pound bars for a utility trailer that only weighs 1000 pounds because I have an HD truck? Right, that makes perfect sense.

By the way, even though I am sure you know this because you have exactly the same set up as I do, the setup of the EQ is no different with the Gen-Y as without it. But of course, you know better having the same set up, correct?

Originally Posted by pteck

Ever wonder why Andy and CanAM are able to do more with less? Follow first principles. Not saying anyone has to use less, but those same principles apply to big trucks and can make for better towing setups that are also more gentle on the Airstream.

No, I don't wonder about Andy and Can-Am because I don't need to. With that said, you are not Andy.

Originally Posted by pteck

You don't have to worry about me. I can well afford any HD truck I like, and that I choose to tow with an even more expensive SUV, but I guess is not here or there. I'll stick with the books, because engineering aircraft isn't as forgiving as dimples.

Good for you. Good luck with your expensive SUV that somehow you already know costs more than any HD truck - because you know, less is more according to you, unless it comes to an SUV. Glad you will stick with the aeronautical engineering books and I am sure your expensive SUV has plenty of storage space for them during your "less is more" travels.

Wow.....just wow.