Self leveling trailer???

[Ditcherman]

Question for the more experienced around here…
The TL;DR: how much benefit would there be to a trailer that self leveled - side to side - while rock crawling/off roading?

Some conversations in the hardcore corner about trailering on Rubicon and Poughkeepsie got my wheels turning here.

I’m also curious as to how many accidents are caused by a trailer tipping over on an obstacle, or going over an edge and pulling the truck with it or at least causing a very precarious situation?

Would love to know if anyone here has experienced or seen it.

Thinking of building a trailer, mostly to put a rooftop tent on so family would be more inclined to camp remotely, get grandkids involved, etc.
This leads to a compromise of building as light as possible but still dealing with substantial weight up high.

If one could build a self leveling trailer (totally doable) that reacted fast enough (not done yet that I have found) would there be a benefit to that on the trail?

I’m assuming air here, hydraulic just adds too much complication for remote use IMO. Maybe there’s a mechanical way to do it?

Does the whole idea add too much complication in your opinion?

 

[MUDZLLA]

The problem is actually one of keeping the center of gravity low enough while travelling so that the tipping angle of the trailer is always greater than that of the vehicle. Keeping the cover light or collapsible would solve the problem.

 

[Ditcherman]

The problem is actually one of keeping the center of gravity low enough while travelling so that the tipping angle of the trailer is always greater than that of the vehicle. Keeping the cover light or collapsible would solve the problem.

I’m kind of exploring managing the tipping angle, keeping the weight more upright and centered while the axle articulates.

Many times the vehicle has the advantage of one axle extremely articulating with the other more level and stabilizing the vehicle. There’s no way to manage that with the trailer.

 

[NMBruce]

I would like to know what you come up with.
My trailer has a 6500lbs axle with 4 adjustable trailing arms and air bags on each side. At first I had the airbags tied together, one filler and it worked great until I got too much top weight and then it would rock side to side, maybe valve could of slowed the air transfer. So then I separate them and that works well as long as I dont put too much air in them, but it's nice, cause I can adjust the pressure for the weight. I also added shocks since the picture, but I need to add bump stops and limit straps. I would love to find a way to easily raise or lower one side or the other to manage the tipping angle. One thing I did to manage the tipping possibility is I went from a Lock N Roll hitch to a Pintle Hitch. The trailer weights around 1500-1700lbs loaded up, I think the Pintle Hitch would stop a roll over at slower speeds, were the Lock N Roll would just let it go.
Here are a few pictures that kind of show the suspension and trailer. The trailer is getting new doors and a new box in the front to hold a ARB fridge.

 

[Ditcherman]

Meant to hit reply to @NMBruce
Nice looking trailer!
I like that trailing arm idea, but it looks like when the axle articulates something has to spin on the threads, that’s it’s not a ball end that pivots?

I’m thinking that smaller diameter airbags will be easier to manage the pressures in and target a good ride. In other words the difference between 5 psi and 20 psi in your bag is huge in terms of ride height and quality, and a smaller bag would be less responsive to that same change, making the target easier to hit.
Edited: After reading what I wrote I think I had it backwards, but don't want to look like I'm covering something up for those that have already read it...I still think the following sentence is true.
That would also require less air in or out, allowing for quicker reaction time while moving.

Here’s what I’ve found so far, made for box trucks to level, lower and raise on 4 corners, just needs to be adapted to not return to normal at 5mph, and be quicker. I think it’d be adaptable.
Some not exactly light reading…

https://media.linkmfg.com/live/assets/literature/H17610_3-3_22.pdf

And here’s a video of an overlander that built a static leveling system himself using Radio Shack parts and writing code on his android phone…

 

[e9999]

my lunettes have 360deg swivel so not much rollover resistance with the pintle hitch. Not that I'd want that.

 

[NMBruce]

Meant to hit reply to @NMBruce
Nice looking trailer!
I like that trailing arm idea, but it looks like when the axle articulates something has to spin on the threads, that’s it’s not a ball end that pivots?

]

this setup was from a 2005 Lexus GX470 I owned at the time. The arms are connect to the axle and frame with these; 3/4" .750" threaded bushing Kit Left and Right 4-link 1/2" bolt hole - https://www.heimjoints.net/products/3-4-threaded-bushing-kit-left-and-right-4-link-1-2-bolt-kit-left-and-right?variant=43249420271785&country=US¤cy=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gad_campaignid=21771220069&gbraid=0AAAAAo75x7C2HZ9ezbGge42Dl6nDCuNNs&gclid=EAIaIQobChMIor75p5DilwMVibMDAB0njiBMEAQYAyABEgJZ5fD_BwE that way the rubber takes the vibrations from the road and lets the arm move up and down. One on the top and one on the side let the axle move up and down without letting it rotate.

 

[NMBruce]

my lunettes have 360deg swivel so not much rollover resistance with the pintle hitch. Not that I'd want that.

mine is just a regular pintle hitch, like we used in the military. it might let it go about 30-35degs and that's about it.

 

[aztoyman]

The title of this thread got my attention so I had to check it out.

IDK how a trailer like this could possibly stay level with the typical spring (leaf or coil or torsion bar) on each side of the axle and the tongue being free to pivot. Anytime one side went over a higher or lower spot than the opposite side, it's naturally going to do whatever takes the least amount of force. If the wheel drops in a hole, that side would follow.

Then I thought, what about the anti rock linkage on rigs. But, I don't think it would work in this case with the tongue not having any resistance to rotating. Then my brain started to hurt and I gave up on thinking about a solution.

Then today I thought about some heavy machinery when I worked at the mines and at a Caterpillar dealership. There were some front end loaders that had a pivoting rear axle housing that had no shocks or springs. It just allowed the rear axle to pivot in the center allowing each side to travel up and down. Side to side articulation. Now I don't think it would work without a front axle in the mix because the tongue will still allow free rotation at the front. Here's a pic of a Cat rear axle housing that I'm referring to as some food for thought. It's upside down. It bolts across the frame rails under the frame. The large bump stop looking this is exactly that. It limits how far it can articulate. Kind of looks like a 40 axle housing where the diff goes in one side and the cover is on the other. Could you combine an articulating axle with this "design" with an anti rock setup?? The down side is no suspension, just articulation.

 

[Ditcherman]

The title of this thread got my attention so I had to check it out.

IDK how a trailer like this could possibly stay level with the typical spring (leaf or coil or torsion bar) on each side of the axle and the tongue being free to pivot. Anytime one side went over a higher or lower spot than the opposite side, it's naturally going to do whatever takes the least amount of force. If the wheel drops in a hole, that side would follow.

Then I thought, what about the anti rock linkage on rigs. But, I don't think it would work in this case with the tongue not having any resistance to rotating. Then my brain started to hurt and I gave up on thinking about a solution.

Then today I thought about some heavy machinery when I worked at the mines and at a Caterpillar dealership. There were some front end loaders that had a pivoting rear axle housing that had no shocks or springs. It just allowed the rear axle to pivot in the center allowing each side to travel up and down. Side to side articulation. Now I don't think it would work without a front axle in the mix because the tongue will still allow free rotation at the front. Here's a pic of a Cat rear axle housing that I'm referring to as some food for thought. It's upside down. It bolts across the frame rails under the frame. The large bump stop looking this is exactly that. It limits how far it can articulate. Kind of looks like a 40 axle housing where the diff goes in one side and the cover is on the other. Could you combine an articulating axle with this "design" with an anti rock setup?? The down side is no suspension, just articulation.

View attachment 4238497

I think anything with 4 wheels and no suspension has a pivoting axle in my world. Farm tractors, backhoes, trencher, even wagons.
I don’t know how an AntiRock sway bar would do anything but stabilize the trailer to the single axle.
The only way to do it is air or hydraulic, and instead of putting more air in the airbag as load increases, you’re actually asking the opposite, when the wheel drops (less pressure) you want to continue inflating that bag. Pretty common on RV self leveling setups.
I actually found a company doing the very thing I’m after on single and tandem axle camping trailers, I need to find the best video and post it, watched too many and lost track.
Very high end campers.

BruderRV Craftsmanship | Handcrafted Australian Excellence

Australian handcrafted excellence. Patented off-road tech and luxury interiors built for the world's toughest terrain, formerly BruderX.

bruderrv.com

 

[ntsqd]

I have two lunettes that are fixed and can't rotate and one that can, but it came with a massive Belleville washer to friction load that rotation so that it takes about 4 feet of leverage for me to rotate it.

If you put a Class 8 ride height sensing valve on each end of the axle or near each tire if ITS then it would dump air out of the high side and add air to the low side. They usually have enough delay that they won't respond to rapid changes, but on something like a side-hill it would try to level the trailer. As a bonus they would also maintain a consistent ride height no matter how the trailer is loaded. Such a system would need a small OBA system or an air hose connection to the TR's OBA system.

ETA: A link tot he type of valve that I'm referring to: Amazon.com: VS228 Air Suspension Height Control Leveling Valve Replaces Freightliner, Peterbilt, Kenvorth, Volvo.VS228, 334-1974, HV9990 : Automotive - https://www.amazon.com/dp/B083F5YN1R

 

[aztoyman]

@Ditcherman, That is an impressive trailer setup. I had no idea stuff like this was out there. Now I understand what you are wanting to do. Way above my design and engineering skills. And my pay scale. I hope you post a build thread if you decide to go for it.

 

[80t0ylc]

What am I missing here? I do not see any advantage or benefit from an off road trailer that self levels while in motion. Now if you’re talking about when setting up for a campsite, that it self levels, I could see the benefit in that. The center of gravity is what’s important for handling off-road. Plus you don’t want any movement on the trailer that could affect the CG. In a precarious situation, it could be the straw that broke the camels back, causing it to flip over. Not trying to be a party pooper, but it just seems like unnecessary complexity.

 

[ntsqd]

I don't think that you're missing anything, but the OP wants it so who am I to judge why?

 

[Ditcherman]

What am I missing here? I do not see any advantage or benefit from an off road trailer that self levels while in motion. Now if you’re talking about when setting up for a campsite, that it self levels, I could see the benefit in that. The center of gravity is what’s important for handling off-road. Plus you don’t want any movement on the trailer that could affect the CG. In a precarious situation, it could be the straw that broke the camels back, causing it to flip over. Not trying to be a party pooper, but it just seems like unnecessary complexity.

I don't think that you're missing anything, but the OP wants it so who am I to judge why?

Actually these are also the kind of responses I was looking for, as well as the positive ones. Tons of trailer experience, the closest I come to off road is a hooper bottom in a side ditch leaning.
So I was really asking about the practicalness of it all, but I’m sure it sounded like I wanted it as I’ve discovered and discussed the options out there.
@80t0ylc the center of gravity being kept low is exactly the issue, and if the trailer leveled in real time it would never lean, never go over, and CG wouldn’t be an issue ever.
Just exploring the “if’s” and I appreciate your feedback on the practicalness of it.

 

[ntsqd]

I guess maybe understanding what exactly you're looking for would help. Are you wanting a trailer that is always dead level no matter how tilted the ground under it is? Or are you wanting a trailer that doesn't lean over when on a sidehill? Or?
My proposed solution would do the latter, but not the former. If you wanted the former it *might* work to use those valves, but oriented with the levers hanging straight down and a swinging mass on the ends of their levers. Can do it with the right sensor, an Arduino, and some pneumatic valves, but what do you do when the system hick-ups or outright fails? Seems like a lot of effort for not much if any gain. But maybe I'm not understanding something.

Just how crazy are you thinking you're going to get while towing a trailer? Little Sluice or more like Hole in the Rock Road? For Little Sluice type trails I'd be looking into how the Aussies built a PTO driven trailer before I'd worry about making it always level.

The first thing is that the trailer does NOT need to run the same size tires as the TR. Usually that results in an excessively tall trailer and related CG. I recall someone here some time ago built their trailer on 37's and wouldn't be talked out of it because "they can all share the same spares." The idea that they can all share the same spares is an OK one, but not really necessary. In the days when that idea was conceived the TR and the trailer both were fairly small (by today's stds) tires and it sort of made sense then. Or maybe they were tyres. I.E. what a Land Rover left the factory with, although the idea predates LR mfg.

 

[e9999]

I suppose one important question -which may or may not be obvious- in all this conjecturing would be which of the 2 vehicles would roll over first?

 

[NMBruce]

I can understand the reason for a self leveling trailer while off road. I did a trip a couple of years ago and my friends behind me thought my trailer was about ready to roll over, they estimated it was leaning around 45 degs, if it had gone over, it would be a job to get it back, and then the damage. This trip was my main reason for getting rid the the Lock N Roll hitch and going to a Pintle hitch.

 

[ntsqd]

It's when straight down from the CG lands on the ground outside of the tire that the angle matters. Until then its just a number that doesn't have a lot of significance.

The lunette with the Belleville spring is the one that I would take on a trip expected to be rough. It will allow the trailer to roll without trying too hard to take the TR with it, but it isn't going to roll easily. The spring acts as a rotational friction brake. A rolled TR is a whole lot bigger problem than a rolled trailer.

 

[Ditcherman]

I have two lunettes that are fixed and can't rotate and one that can, but it came with a massive Belleville washer to friction load that rotation so that it takes about 4 feet of leverage for me to rotate it.

If you put a Class 8 ride height sensing valve on each end of the axle or near each tire if ITS then it would dump air out of the high side and add air to the low side. They usually have enough delay that they won't respond to rapid changes, but on something like a side-hill it would try to level the trailer. As a bonus they would also maintain a consistent ride height no matter how the trailer is loaded. Such a system would need a small OBA system or an air hose connection to the TR's OBA system.

We have those valves on the shelf for our big trucks and trailers, pretty familiar with them. They'd actually have to be set up to work opposite the way of their intended use, to inflate and maintain air in a bag where the tire is dropped away from the trailer. In these high end trailer builds I'm finding a lever attached to a potentiometer and then you can program the system to act normally, raise the trailer when there's a load applied, or reverse it and lower the trailer when a wheel goes over a rock. Bruder's the only one doing this actively, others are just using it for leveling while parked. I think the regular big truck leveling valves would be too slow anyway.

I guess maybe understanding what exactly you're looking for would help. Are you wanting a trailer that is always dead level no matter how tilted the ground under it is? Or are you wanting a trailer that doesn't lean over when on a sidehill? Or?

What I'm curious about is the need for a trailer that has a suspension that keeps the CG from ever going "too" far over the side. Not looking for perfect dead level by any means, and I'm fine with using jacks to level to make sleeping more comfortable.

My proposed solution would do the latter, but not the former. If you wanted the former it *might* work to use those valves, but oriented with the levers hanging straight down and a swinging mass on the ends of their levers. Can do it with the right sensor, an Arduino, and some pneumatic valves,

I'm not following what you're envisioning here yet but that's ok...

but what do you do when the system hick-ups or outright fails?

This is the singular reason that this won't get done, because I won't build a trailer and take it over obstacles where a mechanical or electrical failure would in itself tip the trailer over. I'll just be normal (haha unlikely) and build the trailer with a low enough CG. Not that I wheel that hard anyway, (yet, I'd love to someday) I guess I could do a lot of prototype work on mild stuff.

Seems like a lot of effort for not much if any gain.

I'm picking up on that, not ready to give up on it yet so still exploring, which costs me nothing. Probably good for my brain to have an engaged distraction.

But maybe I'm not understanding something.

Just how crazy are you thinking you're going to get while towing a trailer? Little Sluice or more like Hole in the Rock Road? For Little Sluice type trails I'd be looking into how the Aussies built a PTO driven trailer before I'd worry about making it always level.

Sadly, for me, I don't yet have the experience of those trails so I can't make any comparison. My experience is limited to SW Colorado, Poughkeepsie and Black Bear, and some OHV trails in SW Missouri. So very limited compared to most of you all around these parts. I'm a newb really. I want to get much more experience though, trailer or not.

With todays electric technology, building an incidentally driven axle under a trailer could be much easier I'm guessing...

The first thing is that the trailer does NOT need to run the same size tires as the TR. Usually that results in an excessively tall trailer and related CG. I recall someone here some time ago built their trailer on 37's and wouldn't be talked out of it because "they can all share the same spares." The idea that they can all share the same spares is an OK one, but not really necessary. In the days when that idea was conceived the TR and the trailer both were fairly small (by today's stds) tires and it sort of made sense then. Or maybe they were tyres. I.E. what a Land Rover left the factory with, although the idea predates LR mfg.

Well now you're not talking like one of the cool kids! I wanna be one of the cool kids!

I have noticed that no one has talked about trailers going over and pulling trucks over or trailer accidents in general, which I'm a little surprised about.