Air suspensions vs. spring suspensions

The ups and downs of air spring, leaf spring truck suspensions

Truck-Lite LED light

Every truck suspension option comes with its own unique performance trade-offs. The best choice requires an understanding of how the trade-offs match up to your application requirements.
The right suspension can maintain a tractor-trailer’s road handling and ride quality, and helps minimize the amount of jarring (bumps, vibrations) for improved load-carrying ability. This protects both the trailer and the freight inside from being damaged, and also cushions the chassis from road shock, enabling the driver to steer. The right suspension also maintains the proper axle spacing and alignment.

To help you decide what will work best for you, let’s walk through the basics of the two most common suspensions used in trucking: air ride and leaf spring.

Air ride systems

Air ride uses a variety of valves, airlines and air-spring bags in place of steel suspension. The flexible air-spring bags are made from a woven and rubber-like material. The air supplied to the air-ride suspension uses the same air compressor and air reservoir as a truck’s braking system (See Figure 1).

The supplied air pressurizes the air-spring bags, creating a spring-like motion that raises the chassis from the axle. Air suspensions are more complicated but often provide a smoother ride and keep sensitive cargo for getting damaged. Using air ride can also make unhooking trailers much easier by using the dump valve to lower the truck enough to pull away from the trailer. But if air ride is used on a dump application you must release air pressure before lifting the bed due to the fact that the dump bed at full height will sway back and forth and could tip over.

Leaf spring systems

Spring suspensions use semi-elliptic leaf springs to cushion a load from road shock. As one of the most commonly used suspensions, spring ride consists of several layers of flexible steel strips referred to as a “leaf pack.”

The strips are joined together to act as a single unit. The long and narrow arch-shaped plates are attached to the frame of a trailer, resting above the trailer’s axle. (See Figure 2)

Spring suspensions are sometimes a harsher ride but are often less expensive to repair due to their simple nature. Spring suspensions are generally used for more heavy duty applications where ride isn’t as important and the cargo is not as sensitive (construction, refuse, off road etc.)

With all of the choices on the market, finding the best suspension for your operation can be a daunting task. It’s best to seek expert advice rather than go it alone. Ask for input from a respected sales professional with specific expertise in suspension applications. Make sure they know exactly under what conditions the truck will be operating, and inform them what you are hoping to spend on operational cost. Lastly, try to get feedback from other fleet or maintenance managers who do similar work—ask them what they use and why.

This article was contributed by Kurt Schneider, technical editor for Mitchell 1’s Commercial Vehicle Group. Additional tips for repair and maintenance of Class 4-8 trucks can be found in the Mitchell 1 ShopConnection Truck blog.

You May Also Like

Hydrogen ICE vehicle shipments to hit 400,000 by 2040

Hydrogen ICE vehicles are most attractive for when battery electric alternatives are unavailable or not fit for purpose.

New research from Interact Analysis shows that hydrogen ICE vehicles are in their infancy in terms of rollout. However, mass production is predicted to take off within five years. Although the costs of the engine and the vehicles themselves are relatively low, their running costs are currently high, making the total cost of ownership (TCO) unfavorable. This, coupled with the lack of refueling infrastructure required, means they are less attractive compared with fuel cell and battery electric alternatives. Hydrogen ICE vehicles require a series of minor changes compared with traditional ICE vehicles, including different spark plugs and other changes to materials. On their own, individual changes do not present too much of a challenge, but in combination the total cost of manufacturing the vehicle soars. In addition to this, adding greater complexity increases the potential risks once the vehicle is in mass production.

Five truck trend takeaways from January

Embrace the month and catch up on January’s popular stories and a bonus one too.

Transervice Logistics gets new VP of Northeast operations

Marc Fried will be VP responsible for maintenance and full-service lease operations in the Northeast.

How Decker Truck Line leverages technology to improve operating efficiency

Company ownership remains under the Decker family lineage with Dale Decker’s grandson, Donald, serving as chairman of the board and Donald’s son Dale enlisted as CEO.

Decker-Truck-Line---Mt.-Rainier,-WA-1400
Rockview Farms deploys Volvo LIGHTS project’s final two VNR Electric trucks 

Volvo Trucks deployed its first Class 8 Volvo VNR Electric trucks to fleet operators in 2019.

Other Posts

How the heavy-duty trucking aftermarket meets demands

Talking through the latest parts and technology trends impacting the aftermarket.

Hendrickson-Wheel-End-AFtermarket-Components-1400
Economic downturn could be less severe according to latest data

Data from ACT Research reports the potential for limited interest rate increases.

finance-generic
Leasing and Finance Index new business volume for November up y/y

Volume was down 24% from $11.3 billion in October. Year-to-date, cumulative new business volume was up 6% compared to 2021.

Equipment-Leasing-and-Finance-Association’s-survey-of-economic-activity-1400
December Class 8 intake caps off a robust final four months

At 30,300 units, December Class 8 orders show a positive progression moving into the new year.

Penske-Truck-Leasing-Freightliner