AIR BAG SUSPENSION OR SES PROS AND CONS

What is an Air Bag Suspension System?

Before you can begin to identify clearly the pros and cons of an air bag suspension, you need to understand the design of such a system.

An air bag suspension system is powered by either an electric pump or compressor that forces air into rubber bags typically made out of polyurethane and textile-reinforced rubber.

A compressor inflates the air bags to a certain air pressure. It’s important to note that it’s the air inside the bag that does the work of a spring. (An air bag suspension should not be confused with a hydropneumatics suspension which uses pressurized hydraulic liquid instead of air.)

What's the Purpose of an Air Bag Suspension System?

Air bag suspensions are used to achieve smooth ride quality by replacing the conventional steel-spring suspension in heavier vehicle applications like trucks, tractor-trailers, passenger buses, and even passenger trains.

The ECAS (Electronically Controlled Air Suspension) includes several features such as:

  1. Vulcanized, heavy-duty rubber air springs at each of the vehicles wheels
  2. A storage tank for compressed air which stores air at an average of 150 psi
  3. Valve blocks that direct air to the four springs from the storage reservoir
  4. Air pipes connecting the storage tank to the air bags
  5. ECAS* computer that communicates where to direct more or less air pressure.

*The Electronically Controlled Air Suspension also features height sensors (height-control valves) used to automatically control the vehicles ride height.

Types of Air Bag Suspensions

Sleeve Style

Sleeve-style air springs are designed for lift and ride control. The internally mounted sleeve is covered by a bag, made of flexible, heavy-gauge rubber. The bag is crimped into the spring mount on one end and swaged onto the opposite end, sealing the contents inside.

When air is compressed into the spring, the two-piece sleeve extends, lengthening the assembly to achieve the desired ride height.

Sleeve style air springs are extremely well suited for applications when space is limited, and loads are light. Sleeve-style air springs are perfect for light-duty trucks, custom street rods and track cars.

Bellows Style

Bellows-style air springs are made from heavy-duty, reinforced rubber which is configured with either one or more convoluted chambers.

These air bags are typically larger than sleeve-style air springs, giving them greater load-handling capacity. Because of their size and shape, bellows-style air springs can lift the same weight with about half the air pressure of sleeve-style springs.

The most popular bellows-style air spring configurations include single, dual, and triple chamber design. Bellows air springs are great for heavy-duty applications as long as there is plenty of space for proper installation.

What Are the Main Reasons for Using an Air Bag Suspension?

The Pros (+)

Comfort

Car and truck manufacturers are increasingly turning to air bag suspensions as a viable alternative. Doing away with conventional springs allows for a much smoother ride, something you can’t get with metal springs. After all, you are - quite literally - floating on a cushion of air!

Flexibility

Do you want to arrive at the next family reunion with your vehicle riding impressively low to the pavement while at the same time avoid the inevitable scrapes from a large speed bump? No problem. An air bag suspension allows you the best of both worlds with the flip of a switch. If a heavy load has the rear end of your truck squatting lower than usual, the height-control valve (part of the ECAS*) will keep the load level and stable.

*The Electronically Controlled Air Suspension also features height sensors (height-control valves) used to automatically control the vehicles ride height.

The Cons (–)

The air bag suspension has a few negatives Timbren should mention.

Installation

The biggest drawback of an air bag suspension has always been installing it. Fortunately, the newer air bag suspension kits have reduced the need for cutting and drilling. However, you will need to drill holes to mount the compressor, manifold and tank. If you own a car or light-duty truck, there’s going to be problems with space, not to mention the noise factor whenever the compressor decides to kick in.

Expense

If you want the smooth ride that air bags offer, you’re going to have to pay for it. Without including labor, you’ll be looking at a couple of thousand dollars. If you decide to install it yourself to save on labor costs, there are quite a few components in the box. If you’re not a gear head, the task is probably above your pay grade.

Reliability

Airbags take a pounding. Unless they’re high-quality, they will eventually leak. If they decide to burst on a road trip, it could compromise your brakes, reduce control of your vehicle and lead to an accident.

Maintenance

You need to think twice about using an air bag on your vehicle if you’re the type to ‘set it and forget it’. This complex system is expensive and needs plenty of TLC! Regular checkups are imperative in order to protect your investment.

Conclusion

If you’re considering the purchase of an air bag suspension, you need to be aware of more than just the advantages. Even though you will be rewarded with great ride quality, you should weigh that against the disadvantages:

Air bag suspension cost

The main roadblock to using an air bag suspension is cost. It’s got to be the most expensive suspension system on the market. If you want air bag ride quality, you’re going to have to pay for it. It’s that simple.

Air bag suspension installation

Due to the complexity of an air bag suspension system, installation should be given to a qualified mechanic. Proper installation will ensure that safety objectives are met. Not only that, most kits require professional installation for the warranty to be honored by the manufacturer.

Air bag suspension leaks

Air suspension kits are exposed to harsh road conditions. Like other suspension products, wear and tear will play a factor in the duration of every air bag suspension. Therefore, proper maintenance is required.

Air Bag VS Timbren SES

Similarities

Besides the obvious visual resemblance, what other similarities are there?

Load leveling: Both Timbren SES and the airbag system will improve vehicle handling and its overall performance by reducing suspension sag. Keeping a truck level gives you 3 things:

Reduced body roll and sway

When a truck is sagging too far to the left of the right, body roll and sway immediately becomes a factor.

Improved steering

If a truck or SUV is sagging in the back end, your steering is compromised. This makes it dangerous to safely navigate rough terrain, curves and bends in the road.

Better control

It goes without saying that a level vehicle gives you maximum control reducing the need to ‘white knuckle’ it and lower your speed.

Ease of use: Timbren SES upgrades have always been easy to use. You just set it and forget it. Although airbag systems have not always been simple to operate, recent technical advances with airbag suspensions have made it much easier to use.

Ride quality: In general, both airbags and Timbren springs are designed to improve ride quality in both loaded and unloaded situations.

Warranty: Both Timbren SES and airbag systems (Firestone/Air Lift) come with a Limited Lifetime warranty.

Differences

Technology: Fundamentally, a Timbren SES system uses Aeon™ hollow rubber springs. They do not use compressed air like airbags. When the load is applied, the shape of the spring begins to expand.

However, airbags are… well, rubber bags designed to hold air. The bag expands just like a balloon as air is forced into the rubber bladder.

Installation: Both systems are relatively easy to install. But if you tried to install an airbag system and then follow up with a Timbren kit, you would be struck by two things:

  • The airbag kit has a lot more components than the Timbren SES kit does.
  • The average airbag kit takes about 3 hours to install; the average Timbren kit takes less than an hour.

Adjustability: The most obvious difference between Timbren SES vs air bags is the manner in which they adapt to various road and load conditions.

Airbags can be manually altered to maintain ride height and, to some degree, driver preference. Needless to say, this makes them quite adjustable.

Timbren rubber springs, on the other hand, automatically adjust to variable loads and road conditions. In other words, these rubber springs are self-adjusting. It’s the progressive spring rate built right into Aeon® hollow rubber springs that enables them to adjust automatically.

Maintenance: With Timbren SES, the hollow rubber springs require zero maintenance. Any tweaking or adjusting is done during installation.

On the other hand, airbag maintenance must be performed as often as required to ensure the airbag doesn’t dip below 5 psi. (This is to make sure that the airbag isn’t damaged.) Also, because it’s air that’s doing the heavy lifting, the bladder that holds the air may start to leak which would dramatically compromise the effectiveness of the entire system.

Price: Even though Timbrens comparing price, they are not going to make any judgments regarding cost vs value. (Sometimes a product that costs more is considered to have greater value which, of course, isn’t necessarily true.)

Timbren SES kits are priced somewhere between $225.00 and $500.00.

Airbag kits are priced somewhere between $300 and $1000.00. (Don’t forget: there are more things to buy, like on-board air compressors and other related accessories.)

Summary

This short comparison examines the similarities and the differences between Timbren SES suspension upgrades and airbag suspension kits.

Similarities:

  1. Load leveling
  2. Ease of use
  3. Ride Quality
  4. Warranty

Differences:

  1. Technology
  2. Installation
  3. Adjustability
  4. Maintenance
  5. Price

It’s fair to say that airbag suspension kits bring to the table things that Timbren SES kits do not. And Timbren kits have certain advantages that airbags lack. Hopefully, this article has brought some clarity to the question, “Should I purchase a Timbren SES suspension kit or an airbag kit?” Only you can decide.

So, what is your preference?