The Kenworth W900 is a model line of conventional-cab trucks produced by the American truck manufacturer Kenworth. In continuous production since 1961, the W900 is among the longest-running nameplates in American automotive history. The "W" in W900 denotes Worthington, one of the two founders of Kenworth.
Produced exclusively as Class 8 truck, the W900 is offered in multiple configurations. Alongside several semitractor layouts, the W900 is also produced as a rigid truck. During much of its production, the W900 has been popular among owner-operators. Along with the Peterbilt 359/379/389, the W900 is a popular basis for truck customization, including additional chrome trim, wheels, custom paint, and additional lighting.
In 2018, Kenworth introduced the W990 as a flagship model line; as of 2019, the W900 continues production.
In 1956, Kenworth introduced the 900-series conventional-cab truck, replacing the 500-series introduced in 1939. As with its predecessor, the 900-series shared the chassis of the Kenworth cabover, replacing the "Bullnose" Kenworth COE with the Kenworth K900. As before, a side-opening "butterfly" hood was standard, but a forward tilting fiberglass hood became an option for the first time.
In 1961, Kenworth introduced the W900 conventional as the replacement for the 900-series. As part of several major design changes, the cab was completely redesigned, raising the height of the cab roof and windows and mounting the two windshield panes together. To better allow for engine cooling, the radiator was widened slightly, with the tilting hood made standard. While the headlights remained fender-mounted, the housings were faired into the fenders.
During 1982, Kenworth introduced the W900B as a replacement for the W900A. While largely distinguished by its introduction of rectangular headlamps (though round headlamps initially remained an option), the W900B underwent further modification. To further accommodate increased engine cooling, the hoodline was raised, requiring the cab to be mounted higher on the frame.
Since the introduction of the W900B, Kenworth has introduced two variants of the W900. In 1987, the W900S was introduced, adopting the sloped hood of the T800. In 1990, the W900L was introduced as a longer version, extending the BBC from 120 to 130 inches. Initially produced as a limited edition (to commemorate the W900B model's appearance in Licence to Kill), the W900L went from becoming a limited edition to a full production vehicle. From the 1990s onward, the W900L would become one of the most popular vehicles sold by Kenworth.
Since the introduction of the W900S and W900L, along with changes to the powertrain to comply with upgraded emissions standards, several functional changes have been made to the W900B. In late 1994, the Aerocab/Aerodyne2 became an option for the W900B and W900L; also shared with the T600B. The Aerocab featured a raised roof and a full-width curved windscreen (in one-piece or two-piece configurations); on standard-configuration day cabs, the two-piece flat windshield remains available. On day-cab configurations, the Aerocab roof design introduced an extended-BBC configuration. In 1998, the 86-inch Studio Sleeper was introduced as an option, easily one of the largest factory-produced sleeper cabs ever produced. In 2006, the curved windshield became available on the W900S for the first time.