What's new in: Fifth wheels

Advances continue in weight savings, locking technology

In the words of one manufacturer, fifth wheel technology hasn’t changed significantly in decades. While there have been advances such as cab-actuated air release, low maintenance offerings, no-tilt designs, and the use of lighter weight materials, core systems remain fundamentally unchanged.

“Today, however, we are in the early stages of an evolution in fifth wheel technology,” says Rich Carroll, vice president, sales & marketing, at Jost International. “What we are witnessing now is the automation of the coupling process and the elimination of the manual function of a driver pulling the release handle. The main driver for this shift is the rising cost of insurance and claims within fleet operations.”

Mike Ginocchio, vice president-product planning and market development at SAF-Holland Power Vehicle Systems, notes that there is increasing market demand for lighter weight, user–friendly fifth wheels. “As new features are developed,” he adds, “any changes that affect vehicle dynamics and forces must be reviewed. Shorter stopping distances, changes in vehicle design, load, and vehicle capacity changes all have an affect on the locking mechanism. Continuous improvements in fifth wheel design must always take these changes into account to assure that locking mechanisms perform reliably and safely.”

“Weight savings is very important,” says Terry Mennen, vice president of sales and marketing at Fontaine Fifth Wheel. “One area of focus is the lower assembly, with design initiatives aimed at shortening overall slide length while maintaining strength. The shorter slide reduces weight in the fifth wheel assembly, and it also allows OEMs to shorten mounting angles on the frame, which produces a weight savings.

Aaron Puckett, director of fleet sales at Fontaine, is quick to note that carriers, including truckload fleets, are more interested in weight-saving fifth wheel designs. “They have to address the weight that new engines add to a vehicle,” he says. “It makes the cost per pound for weight-saving technology a different equation.”

The focus does remain on locking system integrity. At Fontaine, the self-adjusting No-Slack lock reduces shock inputs into the frame when braking and accelerating. The company’s latest fifth wheel design also has a positive secondary lock integrated into the pull handle system, and a safety trigger that eliminates the possibility of false coupling. At Jost International, notes Rich Carroll, a simple device called Locktronic is offered. “It’s basically a battery-operated sensor located at the release point of the fifth wheel,” he explains.

“The sensor picks up a magnet embedded on the release handle only if the handle is completely retracted and in the bottom step of the release, indicating a safe condition. “The next logical step in this evolution is validation of safe coupling,” Carroll continues. “Through sensor systems, we will be able to signal that the vehicle combination is in the proper relationship to continue the coupling process and then to provide an indication back to the cab that a successful and safe coupling has occurred.”

This type of technology is available today, and early adoption has begun in various fleet segments. “Our ELI (Electronic Lock Indicator) sensor system continues to grow in popularity as a stand-alone option,” says SAF-Holland’s Ginocchio. “We are now working to connect the ELI system directly with newer vehicle telematics solutions and in-dash displays.”

Proper maintenance is also part of the key to safe, reliable and cost-effective fifth wheels. A thorough program includes lubrication and adjustment, as well as regularly scheduled inspections for damage or other issues, including trailer kingpin wear that can be damaging to the fifth wheel. Lubrication, while particularly important, is a recognized challenge for what is a large area exposed to twists and turns, rain and snow, and highly corrosive road salts.

Manufacturers also note that for safe operation, inflating tractor drive axle air suspensions when a trailer is coupled can cause fifth wheel damage.

Beyond safety and reliability, manufacturers encourage fleets to consider the total cost of ownership, not simply the acquisition cost, when it comes time to specify fifth wheels on new vehicles. They say the process should take into account a design’s ease of maintenance and other factors such as warranty and aftermarket parts availability.

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