Strick's unconventional Cab-Under truck prototype, designed to skirt trucking length laws, returns to the United States, restoration underway

"It's an eerie feeling when you write a check and blindly send it overseas, not sure of what's going to come back." Jon Karel didn't normally conduct trans-Atlantic business, either personally or professionally, and he certainly didn't conduct such business on this scale. Yet about three or four years ago, an opportunity like no other crossed his desk, in part because he was one of the few people in the world who had a good idea of what that check would purchase - one of two prototype Strick Cab-Under trucks that had a hand in changing the American trucking industry for good in the late Seventies - and in part because he could ensure the Cab-Under's return to American highways.

Karel, the vice president for national accounts for Strick Trailers in Monroe, Indiana, had known about the Cab-Under trucks, but never imagined he'd cross paths with them until the day he fielded a call from a company in Germany that had bought the Cab-Under from the bankruptcy sale for Bucking Concepts. Bucking, an Essen-based company that managed a fleet of promotional vehicles, had rented out the Strick as a mobile stage, occasionally fitting it with a clear container for transporting high-visibility vehicles. It was no longer roadworthy in Germany, and the company that had bought the truck no longer wanted it, so they offered it to Strick. Otherwise, it would just end up going to the crusher.

"Strick wasn't all that enthralled with buying it back, but I hated seeing it go for scrap," Karel said. So he wrote the check and started working with his friends and contacts in the shipping and trucking industries to bring the Cab-Under back to the States for the first time since 1982.

Almost a decade earlier, in 1974, was when the idea for the Cab-Under first came to Ron Zubko, the vice president for Strick Trailers. Zubko, according to an interview he gave Overdrive magazine in 2008, said the idea grew out of a desire to increase hauling capacity in the face of restrictive overall length limits in place across the United States at the time. It was "one of those back-of-the-envelope daydreaming things," Zubko said. The owner of Strick at the time, Sol Katz, told Zubko the idea would never work.

As Charley Willmont, who began working for Strick in 1976, explained, the entire trucking industry in the late Seventies faced a "cornucopia of state limitations" on truck and trailer lengths. While the federal government had imposed maximum commercial vehicle widths and weights in 1956 in the same act that established the Interstate Highway System, it had left lengths up to the states, which typically regulated overall length. In response, trucking companies and truck manufacturers turned to cabover tractors, which allowed longer trailer lengths and thus greater load-carrying capacity. By the late Seventies, cabovers became ubiquitous on American highways; a rough count of the tractors appearing on the IMCDB entry for the 1978 movie "Convoy" shows that the movie featured twice as many cabovers as conventionals.

Cabovers had a few other advantages over conventional long-hood tractors, including better visibility and lighter weight, but drivers tended to hate them for their rough rides and for their first-on-the-scene lack of forward crash protection. Also, even the thinnest of crackerbox cabs still ate into the overall length of the tractor-trailer combination. Zubko simply decided to place the tractor underneath the trailer rather than in front of it to maximize that overall length, creating a cabunder rather than a cabover.

(A couple companies had, in fact, previously tried such a configuration. German truck maker Büssing introduced a cabunder in 1965 and American truck maker Butler Brothers had one in the Fifties. Given that the former was an overseas company and the latter built its cabunder primarily for hauling timber, it's likely Zubko wasn't aware of either. For what it's worth, Lloyd Wolf's Wolfwagen concept and the Fageol CargoLiner similarly tried to eliminate the tractor from in front of the trailer but instead accomplished this by integrating truck and trailer.)

As Zubco told the Commercial Car Journal for its May 1977 issue, the idea for the Cab-Under arose from "a series of discussions the Strick engineering staff had concerning the maximization of cube, building the biggest possible trailer within existing state limitations. The biggest box you could possibly make would be 13-1/2 feet high, 8 feet wide and 55 feet long. If you raise the floor of the body to accommodate the tires, you're left with a natural place to put the mechanicals. After that, it was kind of an 'a, b, c' logic that led to the Cab-Under design."

Willmont said that Katz didn't warm up to the concept until his family bought him a Maserati for his 50th birthday, and as he drove the Maserati around, he started to realize that it was exactly the same height as the cabunder tractor that his vice president had pitched. Strick, for all of its history building trailers, had never built a powered vehicle, so it didn't exactly have a department for ideas like this, but he gave Zubko the go-ahead regardless.

Drawing of the first, single-seat Strick Cab-Under prototype

Zubko built some 1:25-scale models to test the feasibility of the design then corralled a group of engineers and commandeered the first garage bay off the Strick headquarters offices. He bought two new International trucks powered by Cummins V903 diesel V-8s, then began adding extensions to the frame of the first truck and constructing the single-seat cab. All of the mechanicals remained stock, save for the relocation of the V903's turbocharger to fit the low profile of the tractor. Just as important as cab placement was the cargo box Zubko designed. No regular trailer body, it instead had retractable legs at each corner that slid into the body and allowed the tractor to drive underneath. The cargo body then mounted to the tractor via a pair of air-operated fifth wheels that raised and lowered the body on and off the legs. Zubko even designed it to mount a converter dolly behind so it could pull a second trailer.

After subjecting the first prototype to 6,000 miles on the company's test track in East Liberty, Ohio, Zubko then built the second prototype with a full-width two-seat cab and a second steerable front axle, the latter to increase gross payload up to the 80,000-pound federal limit, as Zubko told the Commercial Car Journal. By 1978, the second prototype was ready to hit the road, and Strick leased it out to at least two companies - Wayne Daniels Truck in Mount Vernon, Missouri, and Red Ball Motor Freight in Dallas, Texas - for real-world testing.

Drawing of the second, two-seater Strick Cab-Under prototype.

Perhaps the two most important trips that second Cab-Under prototype took, however, were to Capitol Hill in Washington, D.C., and to the University of Michigan's Transportation Research Institute. The former took place as part of the National Highway Traffic Safety Administration's investigation into how to address the plethora of length laws, and though the Cab-Under prototype convinced nobody in D.C. that it was the truck of the future, Karel and Willmont argue that it did help shape the Surface Transportation Assistance Act in 1982, which not only widened commercial vehicles from 96 inches to 102 inches, it also did away with maximum overall tractor-trailer lengths and specified that states could only mandate maximum trailer lengths of 48 feet or longer.

"The Cab-Under was right there in those turbulent times and making a big statement," Willmont said.

Karel noted that it "served as a talking point to be able to move into much larger trailers."

The latter trip took place at the behest of the Teamsters union, which had its concerns about the Cab-Under's safety. According to Zubko, the cab was fitted with a "NASCAR-like roll cage, a half-inch of solid steel," and the Transportation Research Institute's tests confirmed that the Cab-Under couldn't jackknife "because there was no kingpin." However, the tests did criticize the Cab-Under for its performances in collisions with low, fixed barriers and for poor visibility from road surface spray.

Interior of the Strick Cab-Under prototype.

While Karel and Willmont note that the Teamsters skepticism of the Cab-Under had no small part in ensuring it wouldn't reach production, the STAA - which effectively paved the way for conventional tractors and made cabovers obsolete - also doomed the Cab-Under's chances. The same year the STAA passed, Strick sold the Cab-Under, with all hands busy building new 102-inch-wide trailers.

The first, single-seat Cab-Under prototype still exists - Karel knows where it is, but has promised the owners not to reveal its location - and Karel started making plans for the second prototype even before he took delivery of it in 2019, ultimately deciding to send the Cab-Under to Ferris State University's Department of Automotive Management and Heavy Equipment Technology. "It'll give the students there the opportunity to diagnose problems, learn real-world mechanicals, and to discover older technology," he said.

Indeed, as Austin Williams, the advisor for the student group that took on the Cab-Under project, "it's been quite a challenge for them." The group of about a dozen students, who all work on the project outside of their normal class loads, have gone through the fuel, electrical, and brake systems; replaced the turbocharger; and sorted out the tangle of compressed air lines.

V903 engine in the Strick Cab-Under prototype.

"Something like the air lines is just like working in the real world, where you might encounter where somebody mixed and matched valves," Williams said. "It's not just R and R. The students got out their paper and pencil to figure out where things went and what they did. Plus, they stuck with it. They got creative to get it done, especially where common things might not be available off the shelf."

While COVID kept students from working on the Cab-Under for extended periods of time and thus delayed timeline for completing the project, in the last couple of weeks the students wrapped up their work on it and Karel has been able to put the Cab-Under back on the road for the brief trip to his place, where he intends to finish replacing hoses and air lines and start cleaning up the corrosion and miscellaneous added-on equipment that the Cab-Under picked up while in Germany. In the meantime, he's also started to look for a Strick bullnose trailer to use in re-creating the Cab-Under's original cargo box.

Karel said he's not sure where or how he'll display the Cab-Under once it's restored - possibly with the first prototype, given the chance - and at six-foot-eight-inches, he'll likely never get the chance to drive the Cab-Under, but he's at least happy that he got to take a ride in it and that he's made this much progress in saving a piece of highway history.