Bad vibrations

Back in the olden days – about 40 years ago – if you had an air-ride seat and an air-bag suspension over your tandem drive axles, you were sitting pretty.

Those things became more or less standard equipment as the industry rolled on, but along with them, in 1980, came still another air-assisted appliance, the Link Cabmate cab suspension, pioneered by trucker Bill Nibellink from Sioux Center in northwest Iowa. He demonstrated his device by having a visitor stand on the frame rails behind the cab of a Kenworth K100 and watch the cab move separately from the main frame as the tractor was driven up a country trail. That visitor was me.

Kenworth was Nibellink’s first customer, and gradually virtually all major truck builders adopted the product with detail variations to suit individual vehicle models. Today Link Manufacturing, the firm Bill Nibbelink founded and soon sold (he passed away in 2005), is prospering, still in Sioux Center and still making the Cabmate as well as many other chassis suspension and air-management products. Cabmate’s two air springs, shock absorbers and associated piping and hardware are probably under the rear corners of your sleeper and further filter out road-induced vibrations and impacts.

But Link’s engineers have been working to make the now-passively operating system perform actively, using a system called Road Optimized Innovations, or ROI.

With it, sensors and an electronic control module adjust damping rates in advanced shocks and air bags, and do so about 200 times a second, representatives told trade press reporters during an event this week. Sensors include an accelerometer under the cab that measures vertical motions, and the ECU uses proprietary software developed in-house based on road-condition experiences.

More work is done by ROI Cabmate’s advanced shock absorbers, so less air is exhausted from air springs as they soften and harden while cushioning and stabilizing the cab.

The new system also uses an electronic height control valve to keep the cab level. The system has undergone more than 1.5 million miles of testing, much of it by fleet customers in their in-service road tractors.

As with the current product, ROI Cabmate will protect the cab and its contents from damage, keeping it in good shape and preserving or enhancing resale value, said Michael Hof, vice president of new business development. Of course, contents include the driver and any passengers, especially anybody occupying a sleeper bunk while underway. He or she tends to the feel vibration and bouncing because of the bunk’s position, near the rear cab mounts.

“With Link’s ROI Cabmate, operators will enjoy the enhanced ride quality of a vehicle in a constant state of dynamic dampening,” Hof said. “With adjustments being made hundreds of times per second, the system can respond appropriately at each instant, thus drivers and passengers immediately have a very soft shock when traveling on a smooth highway, and a very stiff shock when driving on uneven or off-road terrain. The system deals with unexpected encounters, like potholes, in real time.”

Testimony from those who have tested the new product supports Link’s claims.

“The ride feels highly controlled but soft and smooth at the same time,” said Joel Morrow, senior driver and director of research and development at Ploger Transportation, Norwalk, Ohio, which has several units running in Mack Anthems and Volvo VNLs. A stepson also drives for Ploger, and his ROI-equipped tractor runs over rough streets in Chicago, Philadelphia and New York City, and “he loves it.”

The ROI system’s smoother ride will be especially valuable to someone sleeping in the bunk while the truck is moving. And, he said, it should cushion the engine’s shaking while operated by a stop-start system at night, which can “adrenalin-wake” a sleeping driver whose initial reaction is that “someone’s trying to break into the truck.”

Morrow, who has been closely involved in the fleet’s constant quest for fuel efficiency, believes the ride improvement would allow fifth wheels to be slid forward to reduce the turbulence-producing, fuel-consuming gap between tractor and trailer.

And he thinks wheelbases could be shrunk to improve maneuverability on narrow streets and in cramped loading areas in the old cities.

Fausto Velasquez, a former airline pilot and now president and chief executive officer at TC Consolidada in Mexico City, says testing with four units showed “less bumping, less noise in the cab, and less back pain for drivers, who can drive longer without stopping.” He said he told drivers of two ROI Cabmate-equipped Freightliner Cascadia tractors that a new system had been installed but said nothing to two other drivers in similarly outfitted units. They ran the same route to Tijuana, and both driver groups reported the same positive results.

Charles “Marty” McPherson, a driver with Valley Transportation, a Grand Meadow, Minn.-based hauler of outsized farm implements and construction machinery, said his 2019 Peterbilt 389 has had an ROI Cabmate for the last 50,000 of its 70,000 miles, and he can tell the difference between it and the older system.

“It just rides smoother,” he said. “I like it.”

Hof estimated that ROI Cabmate will add about $2,500 to the cost of a new truck, but that would be made up in greater driver satisfaction and better driver retention for a fleet. The cost of replacing a driver today can be in the thousands of dollars, so one driver who doesn’t quit might more than pay for that higher purchasing price.

ROI Cabmate will first be available in January as a retrofit kit that includes new shocks, air springs, wiring and electronic parts. It can be used to convert existing Cabmate suspensions to the new system. Later, truck builders will offer it on new vehicles. LL

Read Tom’s account of being behind the wheel in an ROI Cabmate-equipped truck here.