Torn Hanger (Info Post)

[Guest]

Rob,

Each time I see this video I wonder how many of these are out there. Should be outlawed. You can see the lateral motion on all the hangers where at 2.11 it can be seen where both axles are moving side to side. Its this motion in the center hanger that I believe needs to be reduced or eliminated to stabilize both axles. Then the fore and aft issues could be solved with the V Clips in the rear hangers.

Below is an article from Road Master which describes some of these issues, but they got the axle rise wrong on which axle is rising on hard braking. As we all know, its the front axle that rises where they state the rear. Doesn't matter though, as hard braking results is less stopping ability, no matter how good the brake system is.

https://roadmasterinc.com/products/t...mfort_ride.php

Jim

[bertschb]

The constant side-to-side flexing of the rear hangers is visible at the start of this LCI video about their aftermarket Correct Track system

Wow! That is crazy Rob. No wonder they fail.

[Cate&Rob]

The constant side-to-side flexing of the rear hangers is visible at the start of this LCI video about their aftermarket Correct Track system. https://www.youtube.com/watch?v=Bp5iRVPwYZg Later in this video, you can see the front tire lock up while the rear tire continues to roll . . . which is the front axle lift during braking.

Rob

[Guest]

This doesn't appear to be one of the typical failures that we've seen in the past with the long hangers. And another thought: Some people try to prevent this by mounting an X-Factor brace between the center hangers. Since this is a rear hanger, I wonder if a center brace would have provided any help at all?

Jim

Jim,

I've taken video under my rig and the only motion that is visible is at the center hangers (short non correct track) in the lateral or side to side direction. I was surprised at how much. This most likely is due to both axles terminating at the center hangers which puts the majority of the lateral forces there. Yet the failures do not occur there from all this motion. Also movement can protect a structure rather than to be too rigid.

The center X factor bracket would provide additional support at the center hanger to prevent lateral axle motion where the center hangers are in bending. Reducing some of this lateral motion may remove some lateral stress from the rear hangers since this would stabilize both axles from side to side motion. But in heavy panic type braking, there are no lateral stresses so to re-enforce the hangers with the V Clip would provide additional support in the longitudinal or front to back directions. For my light weight Imagine, I do not think I need to install the V Clip where I also do not do heavy brake checks. I did however install the X Factor bracket. Cannot tell its there from a handling perspective.

Jim

[Guest]

Hi Jim,

Just wondering what looks different to you about this hanger failure vs previous ones? Not as much rust on the break line as mine, but I still think it is a fatigue failure.

Rob

Rob,

I would need to see the failure with much more detail, and on both the inside and outside legs of the hanger.

Another way to look at this from a load perspective is the rear of the trailer has more lateral motion than the front which is planted to the truck, so the rear hangers could be seeing some lateral stresses along with the longitudinal loads. But if this were all lateral loads we would also see more center hanger failures since both axles terminate at the center hangers where the most lateral motion occurs. Or is this excess motion on the center hanger putting additional lateral loads on the rear hanger where less lateral motion can occur?

This is why I would install V clips on the rear hangers to handle the longitudinal loads and the X Factor bracket on the center hanger to control the majority of the rear axle lateral motion.

We know the front axle will rise in heavy braking which can result in almost no traction on the front axle in a panic type brake apply. This puts most braking and stress on the rear axle, hangers, springs and tires. These forces coupled with some lateral motion as stated above could result in a variety of failures from cyclic fatigue, fracture in a poorly applied weld or more. I think we can all agree the rear hangers are a weak area and should be re-enforced. Folks that feel only lateral forces are resulting in the rear hanger failures, the X Factor bracket on the rear hangers would be a 30 minute install and does not require welding. This bracket prevents the hangers from bending over and will greatly reduce the lateral stresses on the hangers.

Also on a side note: Do most tire failures on the large 5h wheels occur on the rear axle? If so, I believe this would be the result from front axle rise on heavy braking.

The only cure for front axle rise for those that want more effective braking is to install the Roadmaster slipper spring system or the MORryde IS.

https://www.amazon.ca/ROADMASTER-256...01926464&psc=1

Jim

[Cate&Rob]

This doesn't appear to be one of the typical failures that we've seen in the past with the long hangers.

Hi Jim,

Just wondering what looks different to you about this hanger failure vs previous ones? Not as much rust on the break line as mine, but I still think it is a fatigue failure.

Rob

[bertschb]

This is why my Solitude 310GK is at MORryde right now having the new factory suspension replaced before it even ships to my dealer.

[TucsonJim]

This doesn't appear to be one of the typical failures that we've seen in the past with the long hangers. And another thought: Some people try to prevent this by mounting an X-Factor brace between the center hangers. Since this is a rear hanger, I wonder if a center brace would have provided any help at all?

Jim

[Cate&Rob]

This is a good picture of the usual fracture line in the high stress cold bend of the hanger that is further weakened by being in the heat affected zone beside the weld to the frame. Note that the weld above the break looks to be in perfect condition.

It is still my opinion that these failures are the result of the side-to-side flex that happens continually while towing rather than a metal tear during heavy braking. Or perhaps a combination of the two. In my case, most of the separation had surface rust indicating that it had been progressing for a while before it separated completely. I agree that "V braces", sometimes called "V clips", should be added to all "tall" hangers. (see attached picture)

I note that the hanger in the FB picture does not have Correct Track . . . is this LCI or Dexter suspension?

Rob

[steve&renee]

It would be best to have the V clips welded in the rear hangers of these heavy rigs, and/or rigs where disc brakes have been installed. . .

Jim

Wait. I'm planning to install disk brakes on my Solitude sometime this year. What are you saying I need to also do to the spring hangers? Do you have a picture or a link that describes this suggested suspension upgrade?

Thanks.

-Steve

[Guest]

It would be best to have the V clips welded in the rear hangers of these heavy rigs, and/or rigs where disc brakes have been installed. Front axle rise on heavy braking puts undo stress on the rear hangers which will absorb the forces of spring wrap and braking.

Heavy or panic type braking (some test their brakes this way) should be avoided since the heavier the brake apply, the more mass the rear axle will be carrying. This would also put stresses on the rear axle tires as well.

Jim

[howson]

This is from Facebook (obviously). The OP was on the "Grand Design RV Emergency Alliance" page and documented this failure was on a 2018 375M. Looks to me like the rear, street side? It is a very clear shot of the failure and thought it might add to the body of knowledge for those familiar with suspension issues. Guest , Cate&Rob to name just a few.

Only other tidbit of info from the (closed) thread is he found this during his walkaround prior to departure from a campground, so they are in a safe place. (Why, Ar)