As the chief fastener attaching tractor to trailer, a fifth wheel plays a fundamental role in the safety and maneuverability of combination vehicles. Unfortunately, this “alpha part” status often gets overlooked.

“I’d say that fifth wheels are probably one of the most neglected pieces on a truck,” says Eugene Brown, Fontaine’s technical services manager. Some truckers believe that as long as everything seems to be working well, maintenance is unnecessary, Brown says. “That thinking can come back to bite you.”

Brown often sees fifth wheels that clearly didn’t get the regular lubrication and inspection that manufacturers recommend. “A lot of guys don’t get much beyond the ‘tug test’” when hooking to a trailer, he says. “But that won’t tell you much, not even whether the lock is properly engaged.”

This apparent indifference among truckers is fostered by the products themselves, typically some of the most reliable and long-lasting metal on a truck.

“We’re getting about 600,000 miles from our fifth wheels,” says Mike Jensen, a mechanic at Caledonia Haulers in Caledonia, Minn. “If one gives us trouble before that, we’ll just throw a kit in it.”

Caledonia, a food-grade liquid bulk operation, runs 110 company trucks fitted with Holland fifth wheels. Each fifth wheel is inspected annually, as required by DOT regulations, but Jensen says that’s the extent of the service, other than greasing once a week.