MORE...Leveling Travel Trailer with air bags

[Rbertalotto]

So on another thread we went down a path of possibly using airbags or air shocks to level a travel trailer from side to side.

Looking under the trailer it appeared that a single airbag with an arm contacting both axles might be the way to go.



Today a buddy of mine that builds hotrods stopped by and we were looking under the trailer. He suggested I simply remove the bracket that supports the center link on the two leaf springs and insert an airbag here:



He suggested I'd need to install a panhard rod to stop the axles from shifting side to side



I believe a single panhard rod from the perch that will sit ontop of the center link with the airbag above would be sufficient.

Now I'm looking for input and comments from the engineer type folks on this forum. What say you?

[93Cobra2771]

Rbertalotto wrote:
Here's one for you. I spoke to a "suspension engineer" and he suggested that I remove all the leafs but the main one and then add air bags between frame and axle. Let the airbag carry the trailer weight and not the spring. The single leaf spring would now be just to locate the axle.
It was suggested if the trailer doesn't lower down enough, to heat the spring to remove temper. He offered that to level a trailer you can raise the low side AND lower the high side to give you much more range of level.....

Interesting!

Essentially, doing what your engineer suggested is the same as a trailing arm suspension. I think someone suggested that earlier. Using the leaf as the trailing arm is actually a pretty good idea, as it keeps you from having to fabricate anything.

Probably wouldn't be a bad idea to do a little beefing up, such as tying the shackle mounts together side to side and such.

[kcfissel]

Looks like a good system. Interesting mod.

[Rbertalotto]

For $2500.........DONE! And talk about easy loading of a motorcycle in a toy hauler! Lower the whole trailer down to load.


http://www.autoflexsuspensions.com/trailerflex/

Great video of springs VS air bags:

http://www.autoflexsuspensions.com/trailerflex/trailer-videos/

[Rbertalotto]

Here's one for you. I spoke to a "suspension engineer" and he suggested that I remove all the leafs but the main one and then add air bags between frame and axle. Let the airbag carry the trailer weight and not the spring. The single leaf spring would now be just to locate the axle.
It was suggested if the trailer doesn't lower down enough, to heat the spring to remove temper. He offered that to level a trailer you can raise the low side AND lower the high side to give you much more range of level.....

Interesting!

[Rbertalotto]

That ain't rust...that be anodizing! :-0 I love living in New England!

[Lynnmor]

You might want to spray those red rusty springs with Fluid Film.

[93Cobra2771]

True

[Rbertalotto]

Thanks Cobra, I'm going to try that. As I'm sure you understand, I only need to "push down" on the axle on the low side to get things level. I hope I have at least 4" in the static mode, which will give ne over 5" when loaded.

[93Cobra2771]

That was my concern as well - not very much travel in these setups. Some more than others, but most pretty much about what your described.

I don't see the ability to get enough suspension travel to make up for 4-5" difference like you are talking about.

Most I've had was just over 4". I used my Anderson Levelers, and they worked like a champ. I use them just about all the time now.

A small jack might work to see how much "push down" you can get on your axles. Wedge jack between axle and frame rail and see if it will give any.

[Rbertalotto]

I just climbed under the trailer and did a bit of eye balling.....AirShocks it is!

The price is right at around $80 a pair and I can easily weld up a couple brackets to locate them between the frame and the bottom of a axle u-bolts.

Interestingly, I jacked up the trailer to see how much suspension drop I had from static. Only 3/4"...Then I used a ratchet strap to see how much compression and I could only realize 4.5" before the axle impacted the frame. Not much suspension travel in these TT is there....

I need to figure out a way to push down on the axles when the tires are off the ground to see how much actual vertical movement I have. If only a few inches this whole project will be for not as usually, experience has shown, I need about 4-5" of lift on the low side in many camping situations.

Granted these measurements were taken with an empty water tank that sits right over the axles. That will be another nearly 400# pushing down on the axles. Now add an 800 pound motorcycle and that suspension travel is only a couple inches......Interesting.

The suspension,static, without water, there is only 4.5" of space between the frame and the top of the axles. A 2500 pound airbag, deflated is about 3"....That would only leave 1.5" before bottoming out....not good!

[93Cobra2771]

Shocks would certainly help the ride. Most of the shock setups I've seen put the shocks at a significant angle - not sure how much rise you could get out of them.

You are tempting me to go with an onboard air compressor on my truck. Been considering it for quite a while.

I also like the "pull a pin" method, as that would fix any issues should a bag fail.

[Rbertalotto]

One problem I'm going to have is on the drivers side of the trailer....simply no room to do much with the center link, unless I mount the bag between the wheels and shield it with some type of steel cylinder



The water tank is in the way.

Might have to use four airbags , one over each axle point...



The more I look at this, it is becoming clear that air-shocks might win out in the end. A simple adapter plate to the buttom of the "U" bolts and attached to a bracket bolted to the frame.



There is a source on Ebay that will sell you any length and attachment configuration you could dream of...he specializes in the hotrod / lowrider market

Adding shocks couldn't hurt how the trailer rides either....

[Rbertalotto]

Thanks for the encouragement, Richard.

The trailer already has an onboard compressor with a storage tank. There would be no issues keeping the bags inflated.

The bags on my truck lose very little air over the course of a month. And now even Dodge is using airbags as a suspension on their pickup trucks. It's a very proven technology.

In this case, I'd have a stop so should a bag suffer a leak, the tires would not hit the wheel wells. And since I'm keeping the leaf springs, the suspension would simply revert to OEM. In fact, we've thought about having the suspension center link "lock down" in some fashion for travel. When you get to a camp site, pull a pin to release the center link and pump up the bags as needed. No need for a panhard rod in this case. And no worries about a bag leaking while underway.......

[93Cobra2771]

I don't see why the above wouldn't work. Panhard would be a positive location, and since we are talking about a minimal amount of travel at that location you wouldn't have to worry about the axle shift that occurs with a panhard through it's travel stroke.

My biggest concern would be while you are pulling the TT - if the bag were to start leaking down for any reason, then you could have big problems. Of course, plenty of over the road trucks use bags and have their own constant air supply.

Might be a good idea to go ahead and have a small on board air compressor such as from firestone or airlift so air pressure can be steady while on the road. Could even plumb in a tpms so you would be alerted of a pressure failure. Wireless unit like I have with my truck airbags would be perfect, as it's 12v and adjustable. Park, unhitch, then hit the button till you are level. Would need to think carefully about the height of the bag, as you need it to be fully adjustable. Measure weight of camper on each side, then spec the bag accordingly.

That's my biggest concern - lots of non standard parts that could leave you stranded on the side of the road. Unless you carried a spare of everything.

The bag setup like above would also smooth things out nicely with the TT going. Much better than the equaflex/ez flex equalizers that are out there now.

The drive on bags are a pretty neat setup too. But not nearly as crafty as what you are suggesting. most people wouldn't even notice your setup, but they certainly would see the drive on bags.

Keep us updated - would also be better to simply update this thread, as opposed to starting another thread. I like to see threads finished out.