History of Cabover Trucks

Cabover trucks -- also identified as Cab Over Engine (or COE), cab forwards and forward control -- are typically tractor-trailer rigs in which the cab is located directly above the engine and the driver is either sitting atop the front wheels or slightly behind. Many small commercial trucks and passenger vehicles (buses and RVs) also use the cabover configuration.

Origins

The first mass-produced cabover truck was manufactured by the Sternberg Company, later called Sterling, of Wisconsin. It produced a seven-ton COE from 1907-1914. In 1933, Sterling developed the "Camel Back" COE, so named for the slight hump on the nose of the cab. The cab of the Camel Back could be tilted for access to the engine compartment, according to coachbuilt.com.

The Modern Cabover

The White Motor Company developed the modern cabover in 1932 to conform to the 42-foot truck length limit imposed by the U.S. government. The COE design also featured White's "pancake engine," a horizontally-opposed-cylinder engine installed under the floorboards. The 1959-1962 White COE 5000 series featured a cab made of fiberglass to reduce weight, according to the book "Kings of the Road."

Kenworth

Kenworth introduced its version of the cabover in 1955 with an emphasis on driver safety and comfort. The Model COE 521 featured a 72-inch sleeper cabin. It was dubbed the "Bull Nose" for its distinctive nose and was popular among California livestock and produce haulers, according to "Kings of the Road."

Freightliner and Diamond T

Freightliner began building a series of cabovers in 1947 with its famed "bubble nose" models, including the Model 800 COE, which featured a sleeper cabin. Diamond T, a truck maker known for its Art Deco-style light- and heavy-duty trucks, dropped its light truck line in 1951 and focused on larger trucks. It won the National Design Award in 1951 for its COE models. In 1957, Diamond T introduced its diesel-powered, 20,000-pound 430C tilt-cab model. Diamond T's last model before the company merged with White was a tilt COE manufactured in 1966, according to "Kings of the Road."

Cabovers and the Law

Cabovers enjoyed immense popularity because federal and state governments imposed severe restrictions on the length of tractor-trailer rigs. Until 1956, laws limited trucks to 42 feet. The Federal-Aid Highway Act of 1956 increased the maximum length to 65 feet. After 1976, federal and state laws changed to increase the maximum length to 75 feet, according to the Federal Highway Administration.

Out of Favor in the U.S.

The less restrictive tractor-trailer length laws of 1976 quickly pushed the cabover out of the limelight in the United States. Its popularity was mostly due to its convenient dimensions, but conventional truck configurations provided more comfort, less engine noise and greater power, according to "Kings of the Road."

European Cabovers

Although out of favor in North America, Europe's strict tractor-trailer rig dimension laws have made the COE the truck of choice for most trucking businesses. Narrow roads, tight corners and difficult access to urban areas from the highway have made the cabover a necessity, particularly in the United Kingdom. Japan also uses cabovers almost exclusively. German-made Mercedes-Benz and Man, and Japan's Suzuki, are prominent makes of COEs, according to "Kings of the Road."

References

• Vintage cabover truck details
• Sternberg and Sterling trucks
• "Kings of the Road," Rob Leicester Wagner, 1997

Resources

• Federal-Aid Highway Act
• Truck length laws