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Which suspension system offers a better ride for truckers — spring-ride or air-ride semi-trailers?
We asked the experts at Transport Enterprise Leasing (TEL), who have experience providing both options to fleets.
They told us that each type of trailer has its merits, but the advantages of spring-ride suspensions are considerable when comparing maintenance, performance and other factors.
This might come as a surprise to many in the industry, given the widespread use of air-ride trailers on American roads.
“We provide customers whichever trailer option they prefer — but it’s clear that spring-ride trailers are significantly cheaper to operate over the life of the equipment,” said Brandon Lairsen, vice president of trailer leasing for TEL. “They also perform just as well as air-ride trailers in transporting goods safely in all but a few specialized situations.”
Lairsen pointed out that spring-ride trailers feature a straightforward leaf-spring suspension system, requiring minimal maintenance for the first six to seven years of their service life.
Air-ride tailers have more complex suspension systems with more components that wear out over a shorter period of time. For example, an air-ride suspension’s bushings must be replaced every three to five years. This process requires disassembling the bogie, often putting the trailer out of service for a week or more.
In addition, air-ride suspension systems rely on air bags, which are prone to punctures, becoming unseated or deteriorating over time due to dry rot. Replacing an air bag requires disassembling the suspension system, which can be time-consuming and expensive. These repairs also extend downtime for the trailer, impacting revenue.
It’s ironic that air-ride trailers are in higher demand in the United States despite their additional maintenance requirements — especially since spring-ride suspension systems are more prevalent in the typical supply chain.
Consider the logistics of transporting products manufactured overseas.
Lairsen said spring-ride suspension systems are used for most of the journey.
Products are first loaded into metal shipping containers on spring-ride chassis at the manufacturing plant; then they’re carried to the port and transferred to ships.
Once in the U.S., these containers are again placed on spring-ride chassis for delivery to warehouses or distribution centers.
In all, the products travel safely on spring-ride chassis for roughly 90% of their journey before being reloaded onto air-ride trailers for the final few hundred miles to their destination.
So, why are air-ride trailers so popular in the United States?
Some carriers believe air-ride trailers will better protect their cargo, reducing the risk of damage.
However, studies show that when hauling half loads or more, air-ride and spring-ride suspension systems deliver comparable ride quality.
In one study, Schneider, a large carrier, compared the two suspension options using a Society of Automotive Engineers testing program.
Results showed the average ride quality of the four air suspensions tested was similar to that of the industry-standard spring suspension — with spring-ride suspension even outperforming air-ride in certain conditions. The study also found that both suspension types have comparable damping characteristics for controlling motion and oscillation.
TEL’s Lairsen reviewed the data, along with additional research and his company’s own experiences, to develop a white paper discussing the spring-ride versus air-ride question.
The conclusion?
“Spring-ride-equipped trailers meet performance demands in all but a few very specialized use cases,” he said.
Since that white paper was written, improvements in specialized product packaging have eliminated even those exceptions.
Lower maintenance costs and comparable performance are two key reasons to opt for spring-ride semi-trailers over air-ride when expanding or replacing fleet equipment. There are other advantages, Lairsen noted, including lower fuel costs, shorter drive times, and increased payload capacity due to the lighter weight of spring-ride suspensions.
Learn more about TEL’s trailer leasing services and expertise for fleets and used inventory sales.
Linda Garner-Bunch has been in publishing for more than 30 years. You name it, Linda has written about it. She has served as an editor for a group of national do-it-yourself publications and has coordinated the real estate section of Arkansas’ only statewide newspaper, in addition to working on a variety of niche publications ranging from bridal magazines to high-school sports previews and everything in between. She is also an experienced photographer and copy editor who enjoys telling the stories of the “Knights of the Highway,” as she calls our nation’s truck drivers.
