Composite-Spring Trailer Suspension

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SAF-Holland has introduced its latest trailer suspension, the ULX40 UltraLite slider with composite springs. The company says it’s the lightest tandem slider suspension available in North America. Packaged as an all-in-one system, it’s a complete integration of suspension, axles, springs, and SAF drum or optional disc brakes with a 40,000-lb capacity.

SAF-Holland ULX40 UltraLite trailer suspensionThe one-piece composite springs are said to deliver a ride comparable to equivalent air suspensions, while also delivering simplicity, maintenance savings, and longer life.

In fact, SAF-Holland suggests that mechanical suspensions are making a comeback in the dry van and reefer trailer world, though that’s less obvious in Canada than in the U.S. A tridem version of the ULX40 is likely in the works, however, which would appeal to Canadians.

It’s an engineered all-in-one system that is lighter weight, offers a lower total cost of ownership and the industry’s first 10-year suspension and axle system warranty, the company says.

A significant benefit of the integrated package is that buyers are looking at one

complete system from one supplier, as opposed to dealing with several parts and maintenance sources. This also allows for efficient installation at the trailer OEM. There hasn’t been a fully unitized mechanical trailer suspension available until now. And that means it’s all covered by a single warranty — the new ULX40’s 10-year Durasystem warranty is said to be the industry’s first of that duration. It’s also unique because it includes the mechanical slider assembly, the SAF X-series axle, welded bracketry, and the axle connection.

The ULX40 is up to 100 lb lighter than other mechanical trailer suspensions, the company claims. Weight savings can be attributed to the composite springs, which are 80 lb lighter than steel, as well as lighter axles, even though they’re 5.75-in. diameter instead of the previous 5.0.

The high point of the new ULX40 is that SAF composite spring. Lighter yes, but also said to provide the performance of an air ride without the complexity, while maintaining comparable ride quality and handling control.

And the ULX40 is simpler and easier to maintain because it has fewer components – no shock absorbers, no air springs, no height-control valves, and no dock-lock devices.

The ULX40’s proprietary ‘Black Armour’ corrosion- and rust-prevention treatment chemically bonds with metal to form a protective layer, SAF-Holland explains. It’s said to be impervious to water and caustic anti-icing chemicals, offering the protection of galvanization without the weight.

SAF Integral air disc brakes are an optional feature on the ULX40, though they’re more than double the cost of standard drums. They represent 8-12 percent of the company’s trailer build, more than the estimated industry average penetration of about 5 percent.

The new axle, a companion for the air-ride CBX40, is available for order now.

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Rolf Lockwood is editor emeritus of Today's Trucking and a regular contributor to

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