As air suspensions become more and more popular for 4x4s, you may be thinking about converting your solid-axle truck from coil or leaf springs to air springs. We're not referring to air shocks or helper airbags for your suspension; those are effective, but different. We're talking about a complete removal of your truck's coil or leaf springs and subsequent fitment of adjustable air springs as their replacement. Is this new technology? No, semi-tractors and trailers have been using them for years, and with spectacular results. Only lately have manufacturers began integrating the same technology found in semi air suspensions into over-the-counter units that you could install on your vehicle. For instance, the Ford Mighty F-350 Tonka concept vehicle shown at this year's Detroit Auto Show sports eight Air Ride Technologies ShockWave air spring/shock units, and several production 4x4s come with air suspensions as optional equipment.
We visited with the crew at Attitude Performance in Elk Grove Village, Illinois, and watched as they installed Air Ride Technologies components on a modified Dodge Ram pickup. Attitude Performance performs many of these air suspension conversions, and shop owner Matt Dinelli works with each truck owner to design a system based on the amount of lift the owner desires and how he will be using the truck. He then orders the appropriate components from Air Ride Technologies to assemble the system. Air Ride Technologies doesn't offer kits for specific vehicle applications. Instead, you simply order what you need for the configuration you desire. The company can supply nearly all of the components and parts needed to complete a change-over. The system you're seeing on this Ram was designed to supply a generous amount of lift, and to work in conjunction with a front and rear four-link suspension. While you may not be planning on this much lift, this story will give you the general idea of what's involved in an installation. Height is generated by a combination of bag height and cup height, but bags could be easily installed on a stock coil-sprung vehicle (like a Wrangler TJ) by simply replacing the coil springs with the bags (because control arms are already in place) and installing the wiring and hoses. Leaf-sprung trucks would require fitment of upper and lower control arms, but once again, Air Ride Technologies and Attitude Performance have these parts available.
Some of the key ingredients to a functional and durable airbag system are bumpstops of appropriate length (so the airbag doesn't fully compress), and limiting straps (so the bag isn't damaged when the suspension is at full droop). Other than that, the installation is straightforward, but depending on the model of truck, installation may require removal of some spring pads and components as well as welding of new bracketry. The result will be a cutting-edge airbag suspension with adjustability, and given what we witnessed, a smooth ride.
1. Obviously, the first step is to remove the stock suspension. Since the rear of the Dodge would require the most work, we started there by removing the stock leaf springs and the four rivets that hold the rear spring hangers to the frame. Make sure the rear axle is safely supported during disassembly and assembly of the rear suspension. | 
2. Since the plan was to move the air springs inward 1.5 inches (as compared to the stock leaf-spring location) to offer stronger support for the bags (by decreasing the protrusion of the upper cup), the stock spring pads had to be removed from the axletube. For this, Matt used a plasma cutter because it creates less heat, and therefore less chance of axletube distortion. |
3. Next, we installed the Air Ride Technologies upper spring pads on the frame. To ensure perfect placement, Matt mocked up the intended ride height and then checked to be sure there was sufficient suspension travel in both the compression and rebound positions at this ride height. He also checked ground clearance, driveline angle, and wheel clearance. When he was satisfied that all was well, he then marked the mounting brackets at their design height for permanent mounting. It's important to remember that if the air spring is mounted forward of the axle centerline, the air spring's travel will be multiplied at the wheel. | 
4. As he did with the air-bag mounts, Matt analyzed the travel of the rear suspension (as well as the intended airbag location) to determine the proper shock mounting location. Then he removed the stock lower shock mounts with a plasma cutter and welded these Performance Accessories universal lower shock mounts to the axletube in the new location. |
5. The top shock mount is a custom crossmember fabbed from a 13/4-inch round tube that's bolted to the frame. It also acts as a mounting location for the custom exhaust system. | 
6. This is how the left side (the right side is a mirror image) of the rear axlehousing looked before reassembly. When you remove the rear leaf springs, you must replace them with upper and lower control arms to hold the rear axle in place. On the bottom right (under the dual welded-on universal shock mounts) is the mount for the lower four-link bar (this mount is actually the factory lower shock mount that's been widened and gusseted) and on the far left you see the Air Ride Technologies upper four-link mount. The new custom air-spring pad resides in the middle. |
7. Air Ride Technologies offers flat plates and round tubes to allow you to create your own spring cups or pads based on your desired ride height. After figuring the required height, Matt welded them together and drilled mounting holes on the top and bottom, along with access holes to mount the bags to the cups. | 
8. This is how the rear Firestone bag and cup assembly looked before it was installed in the rear of the vehicle. It is attached to the bottom cup and upper plate by a mounting bolt. |
9. The airbags and cups were installed to the mounts using two bolts at each end. Installation of the shock absorbers and four-link bars signaled the completion of the rear of the vehicle. | 
10. Installation of the front bags took considerably less time than the rear bags because the fronts mounted directly onto the stock coil-spring mounts, so there was no need to remove and relocate mounts. Matt simply mounted the upper custom spring cup to the factory spring pad using the existing three factory holes in the spring pad. He welded studs onto the bottom custom spring cup and drilled corresponding holes through the bottom factory spring pad to mount the lower spring cup. |
11. The finished front suspension uses a Superlift dual shock absorber kit and a custom four-link system. The lower control arm connects to the centerlink. The new upper control arm fastens to the factory control arm mount. | 
12. The lower four-link bars from the front and rear suspension connect to an Attitude Performance centerlink that bolts directly to the frame. The upper four-link bar in the rear fastens to the factory leaf-spring mount. |
13. After choosing a mounting location for the Air Ride Technologies control unit, you have several choices of how to wire the unit to control the inflation and deflation of the bags. The owner of this truck wanted ultimate flexibility, so the truck was wired so he could control each bag individually. This is accomplished by simply pushing the buttons upward to inflate, and downward to deflate. The pressure reading shown in this photo is the pressure of both rear bags, and a button allows the driver to toggle between front and rear pressures at will. | 
14. Since this truck won't see gnarly four-wheeling, the owner chose to mount the solenoids, air compressor pressure switches, and sending units for the gauges on the inside of the framerail. This is possible because all of these components are weatherproof. Matt recommends that for vehicles that encounter hard use, these components be wired underhood or inside the vehicle. |
15. Four air compressors (one for each air spring) were mounted under the rear cargo area of the vehicle on a crossmember. | 
16. The compressors feed four 2-gallon air tanks mounted on the inside of the bed. They are the source of compressed air for the air springs. |
Why Air Ride?
Adjustability and ride quality are the top two reasons why air springs are an appealing modification to a 4x4 owner. The ability to vary the amount of air in the bags allows the driver to stiffen or smooth the ride quality of the vehicle at the touch of a button, which is quite handy on bumpy roads or trails.
Much like the adjustable suspension on high-end luxury 4x4s, stiffening the suspension also creates better handling on curvy roads at highway speeds. Of course there's the hauling and towing issue, and the air springs can be easily adjusted to compensate for heavy loads or trailer tongue weights.
Air springs can also be a huge plus on the trail because ride height can be changed easily as the situation demands. Though doing so would require a significant amount of driveline modification, radical suspensions can be created that take advantage of the potential of these units, creating a suspension that could be raised from its default height to almost 12 inches higher. In the real world, though, air-spring suspensions can easily offer a few inches of adjustability for the average truck.