Rear Air Suspension

[blk81shrt]

Im looking into some airride setups for the rear in my truck. I wanna lower the rear a max of 6-7" when the bags are let out. Any ideas on accomplishing this? I would like to do as simple a setup as possible, because my fab skills arent the greatest (but they are progressing). I was thinking i could either buy bag mounts or get them fabbed up for me by a machine shop and them mount them right between the axle and frame. Any thoughts?

[xtreme80]

there's really alot more to it than just bolting on some bags and brackets and going from there.

I would say first on the list would be that you need some way to keep the rear end from moving side to side. Some people choose to use their leaf springs instead of a link setup, but I find that this is cutting corners a little bit. Get a bolt on 6 link setup, and that will include your bag brackets... or at least the lowers. This will also utilize a cantilever system, which means you'll get more lift than a bag over axle setup.

Next thing would be the frame notch. Some people choose to use a regular C-not, but the truck would still be pretty high off the ground. I would suggest an 8 inch frame notch. This is probably the hardest thing to install if you don't have much fab work under your belt. Read up on it, and practice first.

Next thing would be your air management. Are you gonna use air or nitrogen? Most people go with air, but how much? Are you gonna be switch happy or conservative, and only lay it out when you park somewhere? At the minimum, I would suggest a 5 gallon tank and at least a Viair 450 compressor.

Next is valves. Valves control the flow of air to the bags. Opening a valve pushes air in, and closing that and opening another releases the air. If you're just bagging the back, you could get away with using one fill and one dump valve, but this could possibly cause body roll in the rear. I would suggest one fill and one dump PER SIDE. This will also give you independent control of each side.

The rest is just little stuff, like relays and switches, wiring, etc.

Now here's my little piece of advice for you...

I don't know how old you are, or if it matters, or what your overall goal is for the truck, but there's two things that I notice in your posting.

First, if you're anything like most people, you'll get switch happy, play with it all the time, and end up not being satisfied. That's why I strongly suggest that you gather good quality parts from the start. It's much easier and in the long run, will be cheaper.

Next, is that after you do the back, I can almost guarantee you will wanna do the front. It's only natural. Twice the fun, twice as low.

And that brings me to my last statement. If you're putting this much effort into bagging it correctly, why not bag it to lay frame? The front is not hard at all to get on the ground, and if you're gonna link it, and gonna notch it, do it enough to lay it on the ground. In the end, you'll be really happy you did.

There's no feeling like pulling up to a stop light next to an import and setting the entire truck flat on the ground.

I know some people will disagree with some of my info, especially about the link setup, but so be it. I didn't mean to disrespect anyone that uses a leaf spring setup. Also, I'm sure I forgot some things. It's been a year or two since I got out of mini truckin.

Check out www.airride.com or www.***************** to get ideas.

[LowStep79]

You have two options, build a kit or choose this one... It's pricey but it's comepletely bolt on. http://http://www.airride.com/productinfo/airbar.asp

[blk81shrt]

Well that makes total sense. I dunno if i want to go that extreme with my truck. I have my eye on a 68 project that i may look into laying frame. I am only 19 years old and this is my first project so i was thinking i would just do a simple install. I just wanted to stay away from flip kits and i wanted an adjustable rear. But thanks for the great advice and i will definatly consider that for project #2. That being said if i did use the "simple" leaf spring setup, how would i go about accomplishing that? Could I remove pretty much all the leafs and mount the bags in between the axle and frame? I know i would only get at the most 5 inches without a c-section. But that would suit my truck nicely, i only want a mild drop, on this truck. THANKS AGAIN!!!!

[xtreme80]

My only question is, if you only want a mild drop, and you're only looking at around 5 inches of drop, what's the point of air suspension?

You won't be low enough with 5 inches to hit anything, and you'll only be able to raise it higher from there.

But in case this is the route you wanna take, I would go ahead and say to mount the bags and brackets in front of the axle or behind, and make sure that when the truck is as low as it will possibly go without a notch, that's when your bag should be fully deflated.

[blk81shrt]

Heres my thinking:

Flip Kit: ~$200
For the price of a flip kit i should be able to buy some bags and brackets. So if they would give me the drop i need then that would be perfect. Then i could plumb my lines to the rear with some stem valves so i could change the pressure at gas stations and my place. That way i could adjust for towing, cruising or loads. So the brackets could be welded to the frame and axle? The FBI site said that you shouldn't mount bags behind the axle when using leafs. Then could i mount the bags on top of the axle and still retain a few leafs for stability? How about these bag mounts(click to follow link)?



On another note, I was wondering about 4 link setups (Maybe for project number 2?). In your previous post you spoke of 6 link setups. Im having trouble finding anything like that, all i can find are four links. What is the difference? Thanks Again!!!!

[N2TRUX]

Here's an option to consider. It's pretty simple and you don't need to cut the bed...

[blk81shrt]

Thats pretty nice!! What suspension mods are necessary to accomplish that? It looks like a flip kit and some hangers?

[xtreme80]

Originally Posted by blk81shrt

Heres my thinking:

Flip Kit: ~$200
For the price of a flip kit i should be able to buy some bags and brackets. So if they would give me the drop i need then that would be perfect. Then i could plumb my lines to the rear with some stem valves so i could change the pressure at gas stations and my place. That way i could adjust for towing, cruising or loads. So the brackets could be welded to the frame and axle? The FBI site said that you shouldn't mount bags behind the axle when using leafs. Then could i mount the bags on top of the axle and still retain a few leafs for stability? How about these bag mounts(click to follow link)?



On another note, I was wondering about 4 link setups (Maybe for project number 2?). In your previous post you spoke of 6 link setups. Im having trouble finding anything like that, all i can find are four links. What is the difference? Thanks Again!!!!

Ok so here's the thing. You're wanting to try to avoid the higher prices. But the thing is, it's not as simple as just mounting a bag and it drops the truck. If you're retaining the stock leaf springs, what you have to do is actually lower the truck to the lowest point it will go, THEN mount the bags. At this "lowest point" is also when the bag should be deflated. So you're still looking at the cost of a flip kit for something like this, as well as probably new shackles. That's how N2TRUX would have done his setup I'm assuming. I mean there are different ways for everything, but that's usually how people do it.

As for a 6 link, it's basically the same thing as a 4 link, with two extra bars where you would mount the bags. Take a look at my attachment. It's a simple drawing to show you what I mean. The back line would be the frame, with the red circle being the axle. The two lines on the right in grey would be your standard 4 link bars, and the one in red on the left is the 5th and 6th bars, which are used to mount the bags. With this setup, you're looking at roughly twice as much lift, as well as a softer ride, because of the geometry of the suspension.

This may be an easier setup: http://*****************/SuperLliftWishboneKit.php

But with something like that, you're looking at relocating your gas tank or getting a fuel cell.

Let me know if you have any more questions.

Edited to add: I'm not trying to steer you away from the leaf spring setup like N2TRUX... it's not a bad setup at all. My only objection to something like this, and speaking from past experience, this puts alot of unnecessary stress on the leaf springs as well as the bag and brackets. You've got two forces counteracting each other. The bag pushes one way, while the leaf spring pushes the other because of the weight of the truck.

[N2TRUX]

As xtreme80 has well stated, there are many ways to skin a cat. My truck is done the way it is for reasons that might not be important to the next person.

I want to get as low as I could without cutting my bed. I also wanted to keep things simple, and this was the solution. It may not be 100% correct in theory, but I can tell you it works just fine in application.

I don't put a lot of miles on the truck, but it has been driven "almost" every where it goes. That includes several trip from Houston to Dallas and back with no problems.

[454HO]

Originally Posted by N2TRUX

Here's an option to consider. It's pretty simple and you don't need to cut the bed...

Hey Ken, where is the passenger side shock absorber? Am I just missing it in the pics?

[blk81shrt]

Wow i cant even tell you guys how grateful I am for all this information. Im thinking i will just stick to the flip kit. It will be a fairly inexpensive option but it will suit my trucks mild stance. I know I will want to go lower on my next project, but for sure i can consider the vast amount of information when the time comes. THANKS AGAIN!!!!!

[N2TRUX]

Originally Posted by 454HO

Hey Ken, where is the passenger side shock absorber? Am I just missing it in the pics?

No, we ran a mono shock system.

Actually it's just not installed in that pic....

[red02chevy]

Here are some pictures of the frame for my 86. I am running a suicidedoors 4link with a custom made cantilever setup behind the axle. (6link)

[red02chevy]

[xtreme80]

Very nice looking setup red!

[68GMC454]

nice looking set up red...

on my new dually, new to me any way, i found out they did a shakle drop for the rear. looks to be 6 inches or more...now the only problem i see with this is, it still has its full 1 ton spring pack...and in the front of the springs it is real close to the pearch it rides on for the over loads...but it will work for now...i thought i would do a flip kit,, bit there is no room inbetween the springs and the frame...

[blk81shrt]

So the bags are located farther back on the 6 link to pretty much double the lift of the bags. How does your 6 link system ride? When the axle rests on the frame the bags have 0psi right? Cool looking stuff, now i want air ride so bad!

[red02chevy]

Originally Posted by xtreme80

Very nice looking setup red!

Originally Posted by 68GMC454

nice looking set up red...

Thanks a lot guys. I am ready to finish it up.

Originally Posted by blk81shrt

So the bags are located farther back on the 6 link to pretty much double the lift of the bags. How does your 6 link system ride? When the axle rests on the frame the bags have 0psi right? Cool looking stuff, now i want air ride so bad!

the bars are mounted at a 2:1 ratio. They're mounted right in the middle of the lift bar. The bags are completely compressed when the truck is aired out. I mounted those bump stops so that when the truck is aired out the axle wont kill the notch. The truck wont lay frame so all the weight will be right there. I mounted them so when the weight of the truck is on the bump stops it will put the axle right up in the notch.

If you have any more questions or want to see some more photos let me know. Good luck with your project.

[xtreme80]

Originally Posted by red02chevy

Thanks a lot guys. I am ready to finish it up.



the bars are mounted at a 2:1 ratio. They're mounted right in the middle of the lift bar. The bags are completely compressed when the truck is aired out. I mounted those bump stops so that when the truck is aired out the axle wont kill the notch. The truck wont lay frame so all the weight will be right there. I mounted them so when the weight of the truck is on the bump stops it will put the axle right up in the notch.

If you have any more questions or want to see some more photos let me know. Good luck with your project.

Just curious as to why you chose not to lay frame? Everyone's got their own style, but it looks like the only thing needed to lay completely would be to notch it bigger. Were you trying to keep from cutting the bed, or were you just not interested in laying?

[454HO]

Originally Posted by N2TRUX

No, we ran a mono shock system.

Actually it's just not installed in that pic....

So does the passenger shock fit between the bag and frame in the original location with that setup, or did you have to relocate it? And how much does that airbag setup limit the tire/wheel width you can run?

I'd really like to see some lowered setups where the springs, trailing arms, etc, etc are moved inside the frame rails. I want to run super wide rear meats for that pro street look.

[N2TRUX]

Greg, my passenger side is mounted opposite of the drivers side just like OEM.

I have seen a set up where the stock leaf springs were moved inboard of the frame rails. It was a customers truck At Cutten Customs. They were adding an external 4 link because the ride was terrible.

I think moving everything inside the frame reduced the stabilty and caused the truck to have excessive body roll.

[red02chevy]

Originally Posted by xtreme80

Just curious as to why you chose not to lay frame? Everyone's got their own style, but it looks like the only thing needed to lay completely would be to notch it bigger. Were you trying to keep from cutting the bed, or were you just not interested in laying?

There are a few reasons why:

1. I daily drove a bagged 02 silverado that layed frame on billet 22's for 2 years. It just gets old. Draggin is only cool for so long.
2. I wanted to be able to keep my stock gas tanks.
3. With the notch being 1/4" above the frame like it is, you can raise the bedfloor 3 1/2" and it still looks factory. That way you keep all the factory tubs.
4. I didn't want to Z the frame.
5. I wanted to be able to "use" the factory tubs up front and just raise them. If I would have went any lower then i did, it would have been extremely hard to make everything look factory.
6. As you can tell the frame as been sandblasted and will be painted all nice, draggin it down the street will just mess all that up.

Those are a few reasons that popped in my head. I know there's some more but that is enough for anyone to get the point.

Don't get me wrong the truck will be super low. The washers for the control arms should be 1/4" off the ground. Should be about 1/2" from tucking lug out back too.

[xtreme80]

Originally Posted by red02chevy

There are a few reasons why:

1. I daily drove a bagged 02 silverado that layed frame on billet 22's for 2 years. It just gets old. Draggin is only cool for so long.
2. I wanted to be able to keep my stock gas tanks.
3. With the notch being 1/4" above the frame like it is, you can raise the bedfloor 3 1/2" and it still looks factory. That way you keep all the factory tubs.
4. I didn't want to Z the frame.
5. I wanted to be able to "use" the factory tubs up front and just raise them. If I would have went any lower then i did, it would have been extremely hard to make everything look factory.
6. As you can tell the frame as been sandblasted and will be painted all nice, draggin it down the street will just mess all that up.

Those are a few reasons that popped in my head. I know there's some more but that is enough for anyone to get the point.

Don't get me wrong the truck will be super low. The washers for the control arms should be 1/4" off the ground. Should be about 1/2" from tucking lug out back too.

Haha I gotcha. Yeah I drove a nissan frontier that laid frame for a year and a half, it was my daily, and it sucks! But I'm definately interested in your progress on that truck!

[red02chevy]

Originally Posted by xtreme80

Haha I gotcha. Yeah I drove a nissan frontier that laid frame for a year and a half, it was my daily, and it sucks! But I'm definately interested in your progress on that truck!

Other people that haven't driven a bagged truck on a daily basis don't understand it, but, those that have might. lol.

Here is my project thread on another forum that I am a member of. I have been way too busy with work to even be able to touch it. Hopefully that will change soon so i can get back on it.

http://www.gmfullsize.com/forum/show...project+thread