Suspension Makers Work to Counter Effects of Deteriorating Roads on Truck Chassis

The failure of Congress to pass legislation to provide funding to improve and expand the nation’s highway system has left many roads covered with cracks, potholes and uneven pavement, which are creating additional challenges for some vehicle suspension makers, according to company officials.

“Road conditions aren’t getting any better,” said Bill Hicks, head of product planning for trailer systems at SAF-Holland, Inc., Muskegon, Mich. “We are designing for worst-case scenarios and the roads are our proving grounds.”

Hicks said that research and development is in full swing within the industry, with the goal of building stronger and lighter trucks, trailers and their components — such as suspensions. And suspension manufacturers are using technology to determine which materials are best-suited to meet the goals of increased strength and decreased weight, he said.

Fleets are looking for longer-term durability, and the industry overall “has done a good job making suspensions that are durable,” Hicks said. “But if you have 3-inch potholes every mile, you are going to wear out suspensions. The shocks are the first to go. That failure triggers a chain reaction.”

Hicks continued: “Shocks can be quickly replaced by taking out two bolts. You can make a shock that can live forever, but it will cost too much and weigh too much. Just replace the shocks. When you are hitting these [road imperfections] and do it every day, you know something has to give.”

Not all manufacturers, however, feel challenged by the nation’s highway infrastructure problems.

When asked if Ridewell Suspensions, Springfield, Mo., is making adjustments to its systems to handle deteriorating roads, Rick Rickman, vice president of sales, replied, “We are not.” He added, “We haven’t seen or heard of any problems where the deterioration of the highways is having any impact on their life or their performance.”

Rickman said that Ridewell “has always built more of an on/off-highway style suspension that is a little heavier duty than a lot of the competition.” He said that was because the company concentrates “more on tank trailers, heavy-haul [dump trucks], lowboy and the specialty applications where a heavier-duty suspension is generally preferred.”

To handle roadway problems — which also can include corrosion from the use of de-icing and other chemicals — manufacturers are looking to improve their air-ride suspension systems, which have come to dominate the market, outselling mechanical suspensions.

Hicks, who said about 65% of the industry’s trailers are now running on air-ride suspensions, said corrosion concerns have grown in recent years, but that some corrosion preventives end up adding unnecessary weight to trailers.

He said SAF-Holland has a product called Black Armour that “provides an excellent [protection against] salt spray. It’s standard on our suspensions.”

In fact, this spring SAF-Holland began offering the corrosion and rust prevention treatment as a standard feature on some of its products.

Until recently, the industry had not been able to design products that achieved high levels both of ride quality and stability, said Jacob Madden, marketing supervisor for commercial vehicle systems at Hendrickson International, Woodridge, Ill. Madden said Hendrickson recently developed a product called Primaax Ex — a heavy-duty vocational air-ride suspension for the rear axle.

Chuck Cole, spokesman for Utility Trailer Manufacturing Co., City of Industry, Calif., said one reason Utility uses air-ride suspensions has to do with the truckers behind the wheel.

“In today’s world, a lot of driver satisfaction comes from hauling trailers that are easy on the body,” he said. “Companies recognize that trailers equipped with air-ride suspensions ride better and do not bounce around.”

SAF-Holland’s Hicks, who was trained as a mechanical engineer when he joined the trucking industry more than 25 years ago, said he knows that “eventually, over time, if you do it enough, all things will fail.”

But, he added, “Production is getting better, products last longer, and we are pushing ourselves.

“Reduced service life? No one is going to go for that,” Hicks said. “All these things are considered, but at the end of the day, [the product] has to meet a certain criteria for strength.”