In the old days, you could often see cars dragging their rear end, almost bottoming on the tarmac by overloading the suspension. It was a common sight as vehicles were much bigger back then, and the living was easy. As a result of the massive trunks, many families used their vehicles for moving furniture or other heavy cargo.
These days, the same visual effect is achieved using a different technique and for a totally different (and sometimes unexplainable) purpose.
Of course, we don’t exactly say that slamming your car or making it jump in the air is good for the mechanics, but to each his own, right? Consequently, we are not here to judge but to explain how vital suspensions are and what can be done to enhance or completely alter a suspension system into something completely bonkers while staying (relatively) safe.
For a start, we’ll discuss the most exciting (and over-the-top) suspension customizations here — air and hydraulic.
Back to the Basics
The primary purpose of a stock suspension is to provide comfort and a safe ride. A car without any kind of suspension would be incredibly hard to control and almost impossible to steer—not to mention that several components would just break after hitting the first pothole. Indeed, the suspension system has a lot more to do than just comfort.
On a conventional car, the main components are the shock absorbers and coil or leaf springs (the latter is mostly found on older pickup trucks nowadays). However, several high-end cars also come with air and hydraulic suspensions. These act a little differently to achieve the same job and add height adjustment to the mix. Hence, they are often preferred by tuning fans, especially in the hot-rod and lowrider community (not so much on true racers, though, which are better suited with coilovers instead).
How Does an Air Suspension Work?
Air suspensions enable big machines to carry much heavier loads and as such, were pioneered on heavy trucks.
In the case of air suspension, all the metal shock-absorbing bits are replaced with flexible cushions made from textile-reinforced rubber filled with air. The air pressure that the compressor pumps into the air cushions, usually called airbags, is electronically controlled and depends on the load applied on every wheel. In other words, depending on the weight, the compressor will adjust the air pressure in the airbag to keep the vehicle level at all times. This characteristic also means that you can manipulate the height of your vehicle’s suspension on purpose by increasing or lowering the air pressure contained in the airbag. While stock air suspensions often take some time to do their thing, aftermarket ones frequently come with one or two air tanks to store compressed air so it’s available whenever you need it.
Of course, even though air suspensions are more frequently found on luxury cars and lowriders, it can also be used on a wide range of vehicles for different reasons. Dragging your ’29 Ford Model Sedan rat rod or your ’62 Chevy Impala around the hood can be pretty rad as long as you drive on a smooth surface, but once you get to a speed bump, you’ll thank the man who invented this voodoo magic air suspension system. Besides, keeping your 600HP ’68 Camaro straight through sharp corners is also way easier with air suspensions. You can even slap an air suspension on your 2007 Rubicon for insane approach angles and driving through ditches or on top of rocks.
Pros and Cons of Air Suspensions
Pros
- Enhanced ride quality thanks to reduced noise, vibrations, and stress than standard suspensions
- Better loading capabilities due to the ability to keep a consistent ride height
- Better stability when the car is loaded because an air suspension keeps the weight even on all tires
- Offers various suspension heights setup, controlled by a simple press on a button
Cons
- Complicated installation if you are avoiding application-specific conversion kits
- Compressors frequently need to be serviced or replaced, especially on tankless configurations due to the higher duty-cycle
- Airbag cushions can dry out with time and be punctured by sharp objects (looking at you, off-road fan!)
- Moisture in the air can lead to premature rust (make sure to install an inline air/water separator)
- Lost space in the trunk for the air compressor
- More expensive than posh new coilovers
How Do Hydraulic Suspensions Work?
The synonym for hydraulic suspension has to be ’55 Citroën DS and its gliding ride. The system was so advanced that it even let the driver change a tire without using a jack.
In the later years, the hydraulic system on the DS also helped French president De Gaulle escape assassins while running away from over 100 bullets that ended in the tires. The hydraulic system kept the car straight and under the driver’s control, ultimately saving the occupants’ lives.
However, it’s important to note that Citroën’s suspension was actually hydropneumatic. In other words, it used the best of both worlds — air pressure and hydraulic fluid. As a result, it was able to provide both a smooth ride and stable cornering.
Modern hydraulics suspensions are a bit different, as they only use hydraulic fluid. This electronically-controlled pressure builds hydraulic power, then transmitted to 4 separate dampers, causing the chassis to go higher or lower—kinda like how your car’s braking system works.
The primary use of this system is to make the car more comfortable when driving, especially on rough roads. Of course, as in the case of air suspension, a hydraulic suspension is also highly tunable and can be suitable for various applications.
Interestingly, the tuning scene got its hands on hydraulics by force more than by will. Indeed, in the late ’50s, California banned static drops, forcing lowrider owners to think outside the box. The hydraulic suspension came and stayed for good, evolving from a usable suspension to a crazy jumping tool, transforming cars from boring vehicles to true big boys’ toys.
Pros and Cons of Hydraulic Suspensions
Pros
- A lot of ways to customize every damper independently hence all those crazy twisted cockroach-looking cars jumping around
- Can adjust the vehicle height super quickly
- Great for the show (obviously)
Cons
- Kit and installation can get quite costly quite quick
- Hydraulic fluid can make a real mess as the whole installation is prone to defects, leading to more unplanned costs
- Not many auto repair shops specialize in hydraulic suspension maintenance
- A bumpy ride, contrary to Citroën’s smooth hydropneumatic suspension
Air vs. Hydraulics: Which is Better?
If you want something more affordable, go with air suspension. However, you can forget about jumping and driving with your front left and rear right as low as possible, and at the same time, the front right and the rear left 3 feet in the air. Get it?! I’m confused too, but you can’t ignore the whole community that adores this style—and after all, the tuning community is what it is exactly because there’s a little something for everyone.
But I digress…
If you are looking for a smoother ride, you should probably go with air suspensions, as hydraulics can be a bit firmer.
If you like to load and tow, then an air suspension should be your go-to choice.
Last Words
In the end, it all depends on your style and personal preference—there is no right or wrong answer here. Whatever you choose, make sure to properly research it beforehand, as these modifications are not for the faint-hearted. Complicated, expensive, and often irreversible, these mods need to be carefully planned and properly executed.
In the following articles, we will explore the different setups and styles of these two very different yet quite similar suspension mods to help you find out what would be best for your ride.
Talk soon!
Download 2.5M+ car repair manuals here!
