Part 1 - Front And Rear suspension
Well here's my attempt at a Tech article. Since I learned most of what I know about air ride suspension off of sport trucker sites, I figured I would save people the trouble of sorting through allt he bull I found. I don't claim to be an expert on the subject, but I'm just sharing what I've learned so far.
First I'll say this, TAKE PLENTY OF BASE MEASUREMENTS.
Here are some of the setups to stay away from:
Air-Over-Monoleaf - This setup you take all but one spring out, and run airbags over the axle. While in theory this should be ok, the major problem is axle wrap and the high potential of snapping the spring.
2-Link - This setup, you bolt bars to the spring perches like you would a leaf spring, and then to a mount on the frame. The problem with this setup is it eliminates independent wheel travel, and puts stress on everything when there is a need for independent wheel movement.
Reverse setups - Some people, for whatever reason they have, mainly clearances forward of the axle and not wanting to deal with them, will mount the bars running back behind the axle. Problems with this, wheel hop, and its a good way to pull your driveshaft out.
Now since most of you don't care about having a flashy setup to show off, a 4-link will work just fine for you.
For those that don't know what a 4-link is, it is a 4 bar setup, with 2 bars on each side mounted parallel of each other, a parallel 4-link setup, or a triangulated 4-link, where there are two bars run outside the frame, and 2 inside the frame that are triangulated.
With a parallel setup you need to run panhard bar, or a watts link to limit side to side movement of the axle.
With a triangulated setup, the triangulation of the two inner bars is to limit the side to side movement of the axle without the use of a panhard or watts link.
One thing I learned and wish I did right away with my axle, I kept the axle centered when I took off the old suspension and put on the new stuff, but what I should've done is got the axle at ride height, set my pinion angle, and welded it to the frame, then set my links and panhard. It would've saved me the time of adjusting the axle with everything on.
Now onto the front.
Depending on how low you want to go, you may want drop spindles. Some guys get away with stock spindles, some don't, its a crap-shoot.
Cups - Basically if you have to build your own, you want it to be about the outside diameter of your stock springs for the tubing, then you need to secure it to the spring mount, most setups if you have the shock running through the spring, they run some all-thread up through the hole for the shock mount. Or if your upper a-arm doesnt bolt to your spring cup, you could cut it off all together and make a mount out of a plate.
For mounting to the lower a-arm, you could make a cup, or make a plate, don't let anyone tell you a floating setup (where the bag is unsecured on either end) is safe. You'll get a blown bag.
That's it for Part 1, Part 2 I'll get to the cutting, and the air system setup.
