Setting up links for variable height suspension

[Wildman]

Okay maybe that got you interested. So here is the deal.

I have a ORO AiRock air bag system that I want to install a 3 & 4 link suspension on. When driving on the road it has a 3-4" lift and then when off-road it is between 4-5" of lift. So how do I try and setup my links? I know it would be a lot easier for me to switch back to coil springs or coilovers but I need the variable height that the air bags allow me. I am a lower right leg amputee and being able to lower the rig down helps in getting in and out.

This is on a 1997 TJ and I am going to stretch the rear 4-5" and the front 2-3". I know some say this much stretch isn't enough but I have watch TJ's that were stretched out to about 100" WB and felt they worked better off-road and so did those owners.

But what are all these height changes going to do with my numbers? Do I just build it to work at the off-road height and not worry about on the street? I am not wanting to build this with really long arm but more of a mid arm type suspension. I'd like to try and keep my arms 30" or less.
I am running a Ford HP44 in the front and a Tera CRD60 rear. So both axles are high pinion which will help with the driveline angles. I'm currently running a TSL SX 38x12.5x16.5 which once mounted work out to be a 37" tall tire.

For those of you who have not seen the Off-Road Only AiRock system here is some shots of the main parts.

This is the computer that does all the controlling of the AiRock system. The plug on the side is for the wiring harness that goes to 4 height sensors, in cab controller and to the battery for power. The one air fitting on the side is the input and from there the air goes out thru 4 ports on the top that control the air in the air bags.
There are also solenoids inside that send the air to the bags.

You can see the 4 air ports on the top which go to the air bags that have replaced the stock coil springs. This is the side where the solenoid valves are located.

The computer is on this side. It is a active air bag suspension so it will level the Jeep if you have gear in the back or a trailer hooked to the rear. In highway mode which is from 20-50 MPH it will also put air into the airbags to help control body roll. Above 50 MPH it goes into freeway mode it will keep the Jeep level.
Below 20 MPH you are in manual mode. You can adjust the height, lean left or right and so on. In off-road mode your have full control of the air bags and can rock forward where the rear is raised and front lowered for climbing hills. Or rock back where the front is raised and rear lowered for going done steep inclines.
When on sidehills you can lean to the left or right to make it not so bad.

All this is controlled with dash mounted controller.

And on the rear of the controller is 3 plugs. The one on the right is used to connect it to the computer. The serial port is for updates. Not sure what the other is for.

Here is a video of the AiRock in demo mode going thru it's paces.

I have looked at the Savvy mid arm kit and would love to be able to use it but Savvy and Blaine have spent a lot of time to make this kit work within certain parameters and I don't think from what I have read that it would be a good fit. I wish it was as I feel it is a GREAT suspension kit. Also because of the stretch I am wanting to do I think I would just end up ruining this kit.

Now I know it has been discussed a lot that the 3 & 4 link calculators only give a baseline to go off of. But once the vehicle starts moving all those numbers get thrown out the window. But they do help in the design but until I get it built and try it out there isn't anyway of knowing if it will work. I've been looking at using either the GenRight brackets or the TMR brackets for the links. On the frame end for the lower links I have to use a end that will not allow the tube of the link to roll very much to not damage the height sensors. So either a bushing or a Johnny Joint will work from what ORO has told me. On the axle I can use whatever I want and the same with the upper link ends. This is a height sensor on the Nth Degree longarm.

The complete AiRock system

6" lift airbags. They also offer a shortarm 4" kit.


Lets hear your thoughts and ideas.

 

[astjp2]

Well you need to consider that if you are typically driving it at the 4", then you need to compare the antisquat at the 5+ height, if the are close and what you want, you should be ok IMHO. @mrblaine maybe able to walk you through a few options. Good Luck, Tim

 

[Chris]

I can't provide any good input here as I don't know much about this, but I'm definitely subscribing to hopefully read some interesting responses.

 

[Wildman]

Well the one good thing is both the GenRight and TMR rear 4 link brackets are adjustable so I can change my frame separation a little if I need to. Sometimes I liked it better when I wasn't as informed and bolt on kits made it easy. But now that I have learned and am trying to fix what isn't right it takes as much brain power as muscle to work on my Jeep.

 

[Sundowner]

If you want the suspension to work at a height equivalent to a 5" lift, then set it up to work at that height. If you lower the rig just to get in and out, why bother trying to dial in performance for what equates to a static rig, and why bother to try to make things work at a different ride height? If you need assistance getting in and out, then lower the rig for ONLY that purpose and then punch the button that lifts you back up to the normal driving height. Everything else is needless complexity.

 

[mrblaine]

Well you need to consider that if you are typically driving it at the 4", then you need to compare the antisquat at the 5+ height, if the are close and what you want, you should be ok IMHO. @mrblaine maybe able to walk you through a few options. Good Luck, Tim

There is only one way to make it work in one area with a SFA. The only other way is IFS or you would have to double triangulate both ends and eliminate track bars. Anyone who has set up their suspension by adding a lift kit or even removing one inherently understands that you can't dial in the steering until you have ride height defined. Once you change ride height, you have to reset the toe and re-center the steering wheel.

ORO's answer to part of that is their steering for the TJ which completely ignores Ackermann. The end result of that is darty steering that scrubs at low speeds. I've worked with a few locals who tried to come up with ways to make the compromises more palatable and in the end, they wound up ditching the variable height. Having built many air bagged custom vehicles when I was helping the folks at West Coast Customs when they first started out, I was inherently familiar with variable height stuff long before it was put on Jeeps. I don't know that it is possible to dial in tolerable geometry at two disparate heights and have anything but a compromise for each and I certainly would not want to be the one handed the task of figuring it out.

 

[mrblaine]

Well the one good thing is both the GenRight and TMR rear 4 link brackets are adjustable so I can change my frame separation a little if I need to. Sometimes I liked it better when I wasn't as informed and bolt on kits made it easy. But now that I have learned and am trying to fix what isn't right it takes as much brain power as muscle to work on my Jeep.

It is the high quality stereo dilemma. Folks that can't hear the difference don't understand why those who can will spend a fortune on good stuff. One generally only spends that much when they can hear the difference and the more difference you can hear, the more you will spend.

 

[Wildman]

I understand that it isn't a 100% ideal situation and that there are going to be a perfect answer to my setup. Even in the ORO instructions it mentions that if you change your on road height that you need to reset your toe. I am not using their U-Turn steering as I think years ago you told me that it wasn't a good setup.

I'm tone deaf as heck so you really don't want to hear me sing or play an instrument. But just like my putting up with my own voice I will put up with the issues that this systems causes for the benefits it allows me. If I build it to work at one height which is where I will be 90% of the time won't that work?

 

[astjp2]

You know, this bugged me last night, the only way I can see this working is if you only use it for getting in and out of your jeep and dont drive it lowered. Blaine is really spot on about how many changes occur with the height changes. I would just set up your ride height for traveling to be the same as off roading and then just lower to egress and ingress the vehicle. Which is still cooler than anything out there. This will also open up a lot of options for links. Just MHO. Tim

 

[jjvw]

Someone needs to ask this. Since the AiRock is such a big obstacle to build around, what are the other options for getting into the Jeep?

If the AiRock wasn't already there, what would you do to address the accessibility concern?

 

[mrblaine]

Someone needs to ask this. Since the AiRock is such a big obstacle to build around, what are the other options for getting into the Jeep?

Asked, answered and beat to death.

 

[jjvw]

Asked, answered and beat to death.

I remember. If Rick and I are similar in our stubbornness, it helps to ask the same pertinent question at different points in the planning.

I'll admit that I never considered the changes in the steering with the variable ride height. Though it is quite obvious. That is another big check mark in the reconsider column.

 

[Sundowner]

If I build it to work at one height which is where I will be 90% of the time won't that work?

Under that condition, your suspension will work 90% of the time; there will be one or more compromises during the other 10%.

As stated by at least two of us, now: if you're set on the ORO system, lower the vehicle to get in and out, and drive at ONE ride height on both street and trail. No variable geometry. Or, skip the ORO and find the other solutions that will help you. That's really all there is to the matter; no amount of asking in different ways will generate a spontaneous permission slip.

 

[Wildman]

You know, this bugged me last night, the only way I can see this working is if you only use it for getting in and out of your jeep and dont drive it lowered. Blaine is really spot on about how many changes occur with the height changes. I would just set up your ride height for traveling to be the same as off roading and then just lower to egress and ingress the vehicle. Which is still cooler than anything out there. This will also open up a lot of options for links. Just MHO. Tim

Tim,
I agree that using it at one height is the simple answer and makes the most sense. And while I'll admit the KEWL factor does plays into this a little it doesn't trump all issues using this system. But I have it and don't see me removing it. I know it doesn't fit what most would do but it is what I have.

Just like other retired people on this and many other forums I'm not exactly rollin in cash. As nice as it might be to say let's just start all over from scratch that isn't in my list of options. Even if I could figure out a way to get into and out of the Jeep easier without the AiRock every option I have seen is very expensive. I have the AiRock system already so make it work as best as I can.

 

[astjp2]

I would use it, but I would set it up for the 5-6" suspension height and then just lower it to get in and out. Not really an option to use it at 3" for the highway and 5" for offroading unless you hire an engineer to get the steering/track bar to also adjust when you go up and down. If you just lower to get in and out, that would still utilize what you have and meet your need to ease your getting in and out.

 

[Sundowner]

I would use it, but I would set it up for the 5-6" suspension height and then just lower it to get in and out. Not really an option to use it at 3" for the highway and 5" for offroading unless you hire an engineer to get the steering/track bar to also adjust when you go up and down. If you just lower to get in and out, that would still utilize what you have and meet your need to ease your getting in and out.

Additionally, what's the point of dropping two inches just for freeway travel? I really don't see why that would be useful; it seems like a massive and expensive obstacle to overcome.

 

[Wildman]

Under that condition, your suspension will work 90% of the time; there will be one or more compromises during the other 10%.

As stated by at least two of us, now: if you're set on the ORO system, lower the vehicle to get in and out, and drive at ONE ride height on both street and trail. No variable geometry. Or, skip the ORO and find the other solutions that will help you. That's really all there is to the matter; no amount of asking in different ways will generate a spontaneous permission slip.

When did we get back in HS? I'm not asking for a permission slip. I was looking for ideas or suggestions that I hadn't thought of. I'm the first one to admit I am not a knowledgeable guy when it comes to much of things dealing with suspension design.

I would use it, but I would set it up for the 5-6" suspension height and then just lower it to get in and out. Not really an option to use it at 3" for the highway and 5" for offroading unless you hire an engineer to get the steering/track bar to also adjust when you go up and down. If you just lower to get in and out, that would still utilize what you have and meet your need to ease your getting in and out.

I went out yesterday planning on checking out what my different height settings are as it has been a few years since I have been able to use the Jeep. Got the AiRock ECU hooked back up and all the air lines hooked up only to find that my battery that has been on a trickle charger is DEAD so I couldn't run the AiRock thru it's paces. I'm going to get a new battery this week and then before I take everything apart get these numbers so I that I have the correct numbers to put down on paper.

 

[Wildman]

Additionally, what's the point of dropping two inches just for freeway travel? I really don't see why that would be useful; it seems like a massive and expensive obstacle to overcome.

My numbers may be off on the exact amount it will lower when going into highway/freeway mode. In the instructions for the AiRock it states that you should set the on road height where you have 3" of shock shaft showing. They don't give a measurement for where you set your off-road height but I seem to remember it being about an inch taller. I think the purpose of them having a lower on road height than off-road is so you aren't driving on the road with a tall rig. I don't know this as a fact.

Yes I agree with all of you that I should set it all for one height and run with that. The nice thing about this kit is that all these things are programable and you can set each height as you want. I have played around with it before and screwed up how it performed when I tried to set the off-road height to high. I had the air bags set with too much air in them and the Jeep didn't flex worth a damn.

I went back and reset everything and it worked so much better.

In the first picture I had tried to set the off-road height where I think it was at about 6" of lift. It was a really bad idea and it didn't work or flex worth crap. In the second picture I went back to the default setting which I think it around 4" but could be a little higher.

I like jjvw hadn't been thinking about the steering. You and everyone else are correct in setting it to one height and run with it. I guess I wasn't seeing to forest for the trees. I understand that if you change the suspension height you affect the steering.

So if I keep the ride height the same in both modes could I use the Savvy Mid Arm kit? If I rethink the rest of my build ideas and just stretch the rear the 3-4" (Which might not do anything other than decrease my departure angle) would I be able the Savvy kit? Those of you that have installed it? Blaine since you help develop it?

 

[mrblaine]

I would use it, but I would set it up for the 5-6" suspension height and then just lower it to get in and out. Not really an option to use it at 3" for the highway and 5" for offroading unless you hire an engineer to get the steering/track bar to also adjust when you go up and down. If you just lower to get in and out, that would still utilize what you have and meet your need to ease your getting in and out.

The better option is actually the lower height dialed in for highway. Offroad, it would be rare where the offset front axle is much of an issue. Bigger benefit is better handling and lower wind resistance on the highway.

 

[mrblaine]

My numbers may be off on the exact amount it will lower when going into highway/freeway mode. In the instructions for the AiRock it states that you should set the on road height where you have 3" of shock shaft showing. They don't give a measurement for where you set your off-road height but I seem to remember it being about an inch taller. I think the purpose of them having a lower on road height than off-road is so you aren't driving on the road with a tall rig. I don't know this as a fact.

Yes I agree with all of you that I should set it all for one height and run with that. The nice thing about this kit is that all these things are programable and you can set each height as you want. I have played around with it before and screwed up how it performed when I tried to set the off-road height to high. I had the air bags set with too much air in them and the Jeep didn't flex worth a damn.

View attachment 85715

I went back and reset everything and it worked so much better.

View attachment 85716

In the first picture I had tried to set the off-road height where I think it was at about 6" of lift. It was a really bad idea and it didn't work or flex worth crap. In the second picture I went back to the default setting which I think it around 4" but could be a little higher.

I like jjvw hadn't been thinking about the steering. You and everyone else are correct in setting it to one height and run with it. I guess I wasn't seeing to forest for the trees. I understand that if you change the suspension height you affect the steering.

So if I keep the ride height the same in both modes could I use the Savvy Mid Arm kit? If I rethink the rest of my build ideas and just stretch the rear the 3-4" (Which might not do anything other than decrease my departure angle) would I be able the Savvy kit? Those of you that have installed it? Blaine since you help develop it?

The mid arm doesn't really care that much. Get about 4.5" of lift average and the geometry will work plus the rear axle won't be off center at any height. The mid arm front will have less bind when the trackbar pulls the axle over so that is a non issue as well. BTW- I doubt many on here would recognize Larry from the back of his head.