Q: Why Air Suspension?
A: Level your load – passengers, fuel, cargo, trailers, etc. Adjust the height of your vehicle on the fly – improved appearance, obstacle clearance, ease of loading, etc. Get an exceptional ride quality regardless of load – read the next Q/A for the explanation. Get amazing handling stability and performance due to the inherent progressive spring rate that Air Springs offer.

Q: How did Air Suspension begin?
A: First, some interesting history that explains it all; heavy transit buses in the 1930’s were in desperate need for a leaf spring replacement. Passengers that rode the bus from the start of the route would complain about the harsh ride that they experienced before the other passengers got on. This was due to the inherent drawback of all leaf springs; in order to be able to carry the heavy load when the bus was full of passengers, the leaf springs had to be massive and very stiff. Yet, this resulted in an extremely harsh ride when the bus only had a few passengers on it, (similar to today’s factory pickup trucks that “buck” on sectioned freeways while they are unloaded). Air Suspension provided the perfect solution. When the bus was empty, a mechanical leveling valve let air out of the spring to keep the bus at the designed height. Once passengers loaded the bus, the leveling valve added air pressure to the air spring to level the load. This extra pressure also served to increase the stiffness of the air spring. Now the bus had the same ride quality no matter how many people were on it. This simple yet extremely advantageous ability – officially called load capacity vs. ride decoupling – helped the air spring find its place on heavy trucks, trains, and eventually passenger cars. The basic design of the rubber air spring hasn’t changed much over the last 80 years, yet the technology behind the systems that control the air springs have improved tremendously. These advancements have brought improved reliability and capability to Air Suspension and helped the list of applications and uses grow to its current state.

Q: What if an Air Spring blows out while I am driving?
A: This only happens if an air spring or airline is installed INCORRECTLY! If the rubber bellow is rubbing on a metal object during operation, or too close to extreme heat, a rupture will eventually occur. If an airline is installed where it can chafe on a sharp object, or too close to extreme heat, it will eventually fail. Yet, when installed correctly, an Air Suspension System will easily outlast the life of the vehicle. If you’re still skeptical, start looking at all of the truck and trailers that you pass on the freeway and notice the massive Air Springs that hold them all up for millions of miles.

Q: Can I adjust the Spring Rate of my air springs along with the height?
A: Yes, but the Spring Rate will be directly connected with spring height. As you raise the air spring’s height, you will also be increasing the air pressure inside, thus increasing its Spring Rate. Unfortunately, this is opposite from what most of us would want for performance applications, (low and firm for handling, high and soft for mobility). One way to adjust the relationship between Spring Rate and vehicle height is to change the mechanical installed height of the air spring, or make it adjustable. Another way to reduce the spring rate is to add an accumulator tank plumbed in parallel with the air spring (sometimes referred to as a “ping tank”). When you purchase a complete Air Suspension System from AccuAir, you can rest assured that the spring rate and overall ride quality has been optimized for your application. AccuAir and our Industry Partners focus on providing the best possible balance between ride quality, handling characteristics, and ease of installation for your vehicle.

Q: What are Fast Bags?
A: The term Fast Bags means that the Air Suspension System raises and lowers very quickly. The device that determines the speed is usually the solenoid-valves, (although the plumbing size must also be larger to flow enough air to and from the air springs). Most Fast Bag systems use (8) individual 1/2” (or larger) orifice, brass pilot-operated valves mounted near each air spring, with 1/2” or larger airline throughout the system. These setups will usually raise or lower the vehicle in less than 1 second each direction. The result is a very abrupt motion that is unarguably hard on the vehicle and suspension components. We don’t promote these systems for the following reasons:Most of our customer’s would never want their car to move this abruptly.
The individual valve arrangement consumes a lot of space (2 individual valves take up the same space that the entire AccuAir VU4 4-Corner Valve Unit does).
The individual valves require way too many fittings and almost always leak.
Because there are more parts in a pilot-operated valve, they are usually less dependable than a direct driven valve like the VU4.
Pilot-operated valves have a long minimum on time and they are usually large and fast, causing the minimum motion increments for the vehicle to be greater than 1”, which makes setting accurate ride heights very difficult, (although the e-LevelTM System does an amazing job at it).
We feel that the VU4 is the perfect solution to all of these problems and makes for the best overall air suspension system possible. The speed that the VU4 yields is quick, but not radical. In the last few years we have sold a lot of VU4’s to customers that were tired of their large individual valves and became much happier with their entire system after the swap, see Customer Testimonials.

Q: I have heard that it is impossible to have a vehicle with Air Suspension that doesn’t leak, is this true?
A: No. We have found that pipe threads are the most common leak point. Our VU4 Valve Unit eliminates 6 of the culprits and minimizes the number of pipe threads on most systems to 8, instead of 14 or more. For the 8 pipe threads that you will have left, AccuAir includes a special “anaerobic” liquid sealant that has proven unbeatable. AccuAir only uses D.O.T. (Department of Transportation) approved P.T.C. (Push to Connect) fittings and line, which is also essential for eliminating leaks. (Always make sure to cut your plastic line squarely with a sharp blade to avoid tearing the fitting’s o-ring upon insertion). NEVER USE DIAGONAL CUTTERS!

Q: I’ve heard of people using compressed Nitrogen or Helium instead of onboard air compressors. Can I do this with an AccuAir system?
A: Yes, with one massive disclaimer: YOU MUST USE A PRESSURE REGULATOR BETWEEN THE BOTTLE AND OUR SYSTEM. FAILURE TO DO SO WILL RESULT IN A MASSIVE EXPLOSION THAT WILL LIKELY CAUSE BODILY HARM. The pressure regulator must be set below 200 psi for the VU4 valves to operate. Some prefer to use compressed Nitrogen or Helium bottles usually filled at a welding supply shop because it is a silent source of system power that can last for quite a while depending on how frequently you operate your system. Yet, there are some inherent risks and drawbacks to going this route:Compressed Nitrogen or Helium bottles are initially filled to 2,000 psi, which can easily become a dangerous projectile. Some states have deemed them illegal for this reason.
The cost of filling your bottle ads up, usually $20 or more per fill.
Bottles are usually large and heavy making them hard to handle and hard to fit in most vehicles.
If the bottle goes empty and you don’t have a backup compressor, it could leave you stranded.
If you are still convinced that compressed Nitrogen or Helium is what you want, please call to discuss the proper installation and hookup procedures.

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