Is there any component on a Class 8 tractor less glamorous, but more vital, than the fifth wheel?

Well, maybe the lowly wheel end. But nothing enables the concept of a tractor-trailer more than the fifth wheel. The vital connection it makes between a power unit and a trailer filled with cargo is crucial to safe, efficient, and profitable fleet operations.

Fifth wheels have a brutal job. They must maintain a solid, physical connection between the tractor and trailer, endure enormous stress and shock loads, all the while maintaining full articulation to handle maneuvering in tight surroundings. And yet, despite the simplicity of their design, like almost every other component on a tractor-trailer, fifth wheels are undergoing some rather dramatic changes.

The driver shortage is a prime motivator driving fifth design changes, says Pat McNamara, director of national accounts for fifth wheel manufacturer SAF-Holland. McNamara says as older drivers retire, and newer drivers — often without any previous connection to trucking — enter the industry, ease of use is becoming the defining characteristic driving fifth wheel design. Even telematics systems are starting to come into play as fleets look for new ways to help drivers with the coupling process.

“Our new Holland ELI-te Fifth Wheel Coupling Assistant is a prime example of this trend,” McNamara says. “ELI-te stands for Electronic Lock Indicator-technology enhanced — a new, technology-enabled system that eases the coupling of a tractor and trailer, along with the use of air releases to enable quick disconnects, which has continued to grow year over year.”

Jost International last year introduced a series of air-release fifth wheels with sensor technology that allows the driver to confirm that the fifth wheel is safely and properly coupled. The company says aerodynamic side skirts and other add-ons make it difficult for a driver to access the fifth wheel for uncoupling and visually confirming a safe couple.

These are trends that Aaron Puckett, vice president of regional sales for Fontaine Fifth Wheel, sees as well. “We are seeing definite trends toward a preference for in-cab air release options,” he says, noting that this trend is also driven by driver retention issues. “Fleets are investigating inspection lights, cameras and sensors,” he adds. “But so far, most have not made any commitments on these new technologies based on the added acquisition costs.”

Other trends Puckett sees are shorter air slides and lower fifth wheel heights, which he says are now the normal spec on most new truck purchases. Most of the air slides Fontaine sells today are 12-inch slide lengths with a 6.75-inch fifth wheel height. It is also common to see fleets spec’ing removable slide stops to lock down the air slide — even if it’s an option they never use themselves. “They buy the truck with an air slide for the resale value but lock down all slide movement while the truck is being used in their fleet,” he explains. If you plan to keep your truck for less than six years, you most likely want to go with an air slide system. “If you’re going to keep a truck for more than six years, and really do not require an air slide, then going with a stationary mount will reduce both your acquisition costs and your fifth wheel weight,” Puckett says.

Do you have the right fifth wheel?

Application remains the top criteria for spec’ing a fifth wheel correctly, both McNamara and Puckett say. There are a multitude of signs fleet managers and technicians can look for that are clues you have the wrong fifth wheel.

You need to start by talking with your drivers, Puckett says, to figure out if your fifth wheel spec is working properly out in the field. If a fifth wheel is improperly spec’d, drivers will often report locking issues or complain of slack they feel between the truck and trailer. And even just eyeballing your trucks can tell you a lot about the fifth wheel, he says, as incorrect fifth wheel heights or specs can cause issues with landing gear deployment or overall trailer height.

Technicians can also give you valuable feedback on fifth wheels, Puckett notes. “Cracks in the fifth wheel that appear over time are another sign you need to reexamine your spec,” he says. “But if a new fifth wheel is being properly maintained and your maintenance team is seeing major repairs within the first 24-36 months, that’s a leading sign of a poorly specified fifth wheel.”

McNamara advises fleet managers to watch for locking components and/or top plates that have excessive wear, cracks, distortion, or loose bracket pin holes or lock pin holes. “If you do find any of these issues, then working closely with the dealer when spec’ing the fifth wheel is vital for assuring the tractor is properly spec’d for the application,” he says. “And in extreme cases, where you’d having difficulty getting the answers you need, you can always reach out to your fifth wheel manufacturer and talk with an application engineer to get help with application issues.”

At the same time, McNamara says, fifth wheels often take the blame for operational issues when other components are actually at fault. “Technicians should inspect for unusual wear on locks as well as the top plate itself,” he says. “In addition to the fifth wheel, it is important that fleets also inspect trailer kingpins to ensure that they meet all wear specifications, ensuring that the fifth wheel can operate properly. Finally, it is key that all PM programs have a visual inspection to check for any broken components. The technician should use the lock tester to ensure the wheel and lock set is operating properly, and that the wheel in use meets the specifications of [the] application.”

Saving weight

In addition to driver issues, another clear trend in fifth wheels in some applications is the push for lighter weight components that can withstand the daily rigors of trucking while helping maximize payload. McNamara says SAF-Holland has been a pioneer in designing lighter-weight fifth wheels with its FWAL aluminum design that weighs in at a featherweight 157 pounds. “That is significantly less than a steel or ductile iron fifth wheel,” McNamara says. “But the FWAL is still rated for 55,000 pounds vertical capacity and has optional air release.”

Fontaine has its own lightweight fifth wheel line, which Puckett says weighs around 60 pounds less than previous designs, but is still tough enough to handle standard to moderately severe applications.

“We do not recommend spec’ing lightweight fifth wheels for most vocational applications, however,” he cautions. “Steel fifth wheels are still the preferred spec for tough vocational jobs. And even when you’re spec’ing a stronger fifth wheel top plate, it is vital to make sure to ask the dealer if the lower mount, air slide or stationary, is rated for vocational applications to ensure durability in the field.”

Lighter, safer, and easier to use, but still tough enough to handle the task at hand. It’s a maxim that holds true across trucking today. And even the lowly, unsung fifth wheel is getting updated as this trend gains speed across the industry.

Related: Why Proper Fifth Wheel Maintenance is Important