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.
In production for over 57 years, the Kenworth W900 has been produced in three basic generations: the "narrow-hood" W900 (1961-1966) and the "wide-hood" W900A (1967-1982) and W900B (1982-present). Currently (as of 2018) there are three versions of the W900B sold. Alongside the standard W900B, there is the extended-hood W900L (introduced in 1989) and the sloped-hood W900S (introduced in 1987); the W900S is similar to the T800, except for its set-forward front axle.
In contrast to the 900-series and 500-series Kenworth conventionals, the cab introduced "bulkhead-style" doors (with full-length hinges). In another change, the roof panel was changed from metal to fiberglass. While functionally different, the W900 retained the wide-style vent windows, with door handles mounted below the windows.
In 1967, the W900 underwent its first major change and was renamed the W900A. To accommodate larger diesel engines, the hood was widened several inches to further increase radiator size. For 1972, the doors of the W900 were changed, with the model adapting larger windows, narrower vent windows; for ease of use, the door handles were re-positioned to the bottom of the doors and changed from a lever-style to a pull-style configuration. In 1973, the Kenworth badging was changed, with a redesigned grille emblem and hood badging. And in 1974, A new 60" flattop double sleeper was available as a factory option
In 1976, Kenworth introduced the Aerodyne sleeper cab for the W900A. Distinguished by its twin skylight windows, Aerodyne was the first factory-produced sleeper cab with a raised roof.
After the 1982 introduction of the W900B, the W900 continued production in Mexico (Kenmex), adopting the latter model's rectangular headlamps.
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.
Structurally, the W900 shares commonality with a wide variety of Kenworth trucks produced in North America through a wide variety of applications.
In 1961, Kenworth introduced the K100 cabover model line alongside the W900 conventional ("K" standing for Kent, the first half of Kenworth). While using a different frame and cab, the K100 models shared similar build charcterstics with the W900's and other models, such as free-fit bolted frames, and bulkhead doors with piano-style hinges.
As length restriction regulations were liberalized in North America in the early 1980s, the demand for cabover-style semitractors fell sharply, with the K100E ending production in 2004. After its discontinuation in the North America, the K100 remained in production in Australia until 2011, when it was replaced by the K200. While structurally similar to the K100, the Kenworth K200 features a redesigned interior and exterior.
Introduced in 1972, the Kenworth C500 is marketed nearly exclusively in severe-service configurations. Sharing its cab with the W900, the C500 uses a model-specific chassis, offered with multiple axle configurations (including versions with twin steer axles).
Introduced for 1985, the Kenworth T600 is the first aerodynamically-enhanced semitractor, with a sloped hood, skirted lower body, and bodywork that closely integrates the front fenders and bumper. Sharing the cab and frame of the W900, the T600 differs largely with its radically sloped hood, set-back front axle, and air cleaners set under the hood. Although marketed alongside the W900 for its entire production run, the T600 was not developed as its successor; during the development of the T600, Kenworth achieved over 20% better fuel economy (compared to the W900).
Following the introduction of the T600, Kenworth would debut a wide variety of sloped-hood trucks based on the T600 and W900, including the T400 regional tractor, T800 heavy-duty truck (which remains in production as of 2018), along with medium duty trucks (the T300, followed by the T170/T270/T370/T470). While featuring changes to its front bodywork, suspension, and frame, the 2008-2017 Kenworth T660, which replaced the T600, shares cab/sleeper commonality with its predecessor and the W900.
Through the late 1980s and 1990s, as a response to the success of the Kenworth T600, other North American truck manufacturers would introduce aerodynamically enhanced semitractors of their own, with the Ford Aeromax, International 9400, and Peterbilt 377 conventionals entering production along with the Peterbilt 372 and Freightliner Argosy cabovers.
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