Kenworth, Trucks

Major Makeover for Kenworth’s Cab-Over

There’s no doubt about it! Inside and out, the K200 represents the most dramatic and most overdue design change in the 40 year history of Kenworth’s stalwart cab-over. In this detailed report, STEVE BROOKS is invited behind the wheel to sample this remarkable rework of the venerable K-series, arguably the biggest single development from the Kenworth camp in decades.


In the broadest terms of truck design, evolution can perhaps be loosely defined as those gradual updates and modifications which change and enhance the style and performance of a particular model over time.
Revolution on the other hand occurs when a great heap of major developments are implemented all at once, dramatically altering a particular design to the point where it not only looks vastly different but is also fundamentally better in function and form than anything that went before it. Subsequently, it becomes the foundation for future designs.

Kenworth K200

In our estimation, Kenworth’s K200 probably sits somewhere between the two definitions. Yet such is the extent of change on a series which from day one has been a cornerstone of Kenworth’s Australian operation, that the lean is definitely more towards revolution than evolution. Revolution with a small ‘r’.

Whatever the judgement though, the K200 – or something akin to it with the enhancements to overcome a few increasingly evident flaws in the internal design of Kenworth’s crucial cab-over – has been a long time coming. Forty years have passed since the first truck, a K-series, rolled out of Kenworth’s Bayswater (Vic) factory and since then more than 11,000 cab-overs have followed, easily making K-series the most enduring and successful of all Kenworth models. Indeed, one of the most enduring trucks to ever compete on the Australian market.

In the K200 demo truck, control tower for the Eaton Ultrashift-Plus automated shifter actually infringed on movement from seat to bunk more than its manual counterpart with a collapsible gearlever. Automated or not though, space and convenience for the driver are massively improved in the K200.

Of course, much has changed over those 40 years, not least America’s departure from heavy-duty cab-over trucks which effectively left Kenworth’s Australian operation on its own when it came to continuing development of the K-series. Yet many years back, around the late ‘80s, there was actually plenty of talk of a completely new Kenworth cab-over design being developed at Paccar’s Seattle headquarters in the US. Corporate colleague Peterbilt had already produced a radical new cab-over model and most pundits thought it inevitable that Kenworth would eventually follow with something similarly advanced.

However, changing US regulations continued to favour conventional designs, meaning that Peterbilt’s new cab-over would be relatively shortlived and Kenworth’s anticipated new model would forever remain nothing more than a rumour. As for some suggestions at the time that Australia should design and produce an entirely new cab-over of its own, well, in a relatively small market like ours the costs are simply way too high – particularly given the engineering complexities of the cab-over design – and the returns way too low to justify such an expensive endeavour. Thus, the K-series was here to stay.

Still, cab-over acceptance in Australia remained strong, buoyed greatly by the ascendancy of B-doubles. Meantime, Kenworth’s extensive engineering capabilties and world class manufacturing operation at Bayswater combined to put the local outfit in the box seat, providing the ability to quickly react to changing operational and regulatory landscapes.

It’s fair to suggest, for instance, that Kenworth Australia’s capabilities and the burgeoning B-double business delivered a much needed shot in the arm for the K-series, with no better example of this than the cab-over’s adaptation over the years to the various regulatory requirements of B-doubles and its subsequent success as a market leader in B-double roles.

Steppin’ up. The K200 is a tall truck but the steps are evenly spaced and provide sure-footed access with conveniently sited grab rails for support. On the passenger side though, there was the surprising absence of a grab handle on the inside of the A-pillar.

In fact, the K-series has probably undergone more development work over the past few decades than any Kenworth model to ever compete on the Australian market. Gradual changes based on the K100 platform have seen the evolution of versions from the K100C to the K100E, K100G, the K104 which marked the arrival of engineering modifications specifically tailored to toughening emissions standards, followed soon after by the marginally modified K104B.

In engineering terms, however, the biggest change came a few years later with the K108, a derivative created alongside its ’08 conventional counterparts to meet the massively increased cooling requirements of EGR engines complying with the ADR 80/02 emissions standard which came into effect early in 2008.

Then almost three years later, coinciding with the introduction of the ADR 80/03 emissions standard on January 1 this year, Kenworth late in 2010 shocked the socks off everyone with the launch of several stunningly restyled conventionals. The biggest shock of all though came with the unveiling of the K200.

As several senior Kenworth people have explained when asked why it took so long to introduce a vastly restyled and modernised cab-over flagship, the ’08 range consumed so much engineering time and energy – not to mention funds – in meeting ADR 80/02 that there was little opportunity to concentrate on anything other than the detailed requirements of the new emissions standard.

According to the same people though, there had been firm plans for a number of years to completely redesign the K-series. Thus, with the engineering demands of ADR 80/03 substantially less than those of the previous standard, Kenworth had both the time and the resources to go full throttle on the creation of a vastly changed cab-over series.

New looks

Development of the K200 was unquestionably one of the best kept secrets in the history of Australian truck design and despite a typically lengthy test program across much of Australia, Kenworth still managed to keep the new model away from prying eyes.

Sure, we expected a modified range of trucks fitted with a diesel particulate filter (DPF) to meet the 2011 emissions standard, but there was no indication whatsoever that Kenworth would go to such great lengths to

address the criticisms which had dogged the K-series despite its obvious success over so many years. Those criticisms, of course, centred largely on the driver environment with complaints of poor access into and inside the cab, but it’s on the outside where you’re initially left in no doubt that K200 is boldly different to any of its predecessors.

To quote Kenworth, ‘The K200 story starts with dramatic new styling from a wider and lower grille opening and chrome surround. This larger opening, along with the standard contoured FUPS bumper, promotes greater airflow through the new cooling package which includes a new charge air cooler, moulded fan shroud and a repositioned engine to optimise exit air flow.’

The size of the radiator is, however, unchanged. According to our sources, Kenworth was able to achieve considerable gains in cooling efficiency by concentrating on air management, specifically streamlining airflow into and out of the radiator through a redesigned fan shroud.

Meanwhile, cab height has been raised by 50 mm with considerably more shielding under the cab and engine tunnel to substantially lower heat and noise intrusion.

Critically though, considerable engineering emphasis was applied to cab access. Again quoting Kenworth, ‘The new cab access system provides a larger free flowing top step that supplements existing access standards … and allows the driver to maintain continuous three points of contact at all times by utilising grab rails and steps.’

Additionally, there are LED step lights integrated with the remote control central locking system, automatically lighting the steps when the cab is unlocked. Also, the doors have been redesigned with wider armrests integrating switches for mirror adjustment and the standard electric windows.

There are also new seat options providing driver and passenger with 30 mm more shoulder room and greater leg room on the passenger side. What’s more, there’s also space under the bunk for two amply sized slide-out drawers which can be optionally equipped as 30 litre fridges. Likewise, the overhead console includes an additional storage locker and recessed panels for fitment of GPS navigation or other driver information displays.

The truly big achievements on the inside though are what Kenworth describes as an ‘almost flat’ cab floor and a clever fold-away gearlever, each combining to overcome historic K-series complaints of restricted space in the driver’s area and poor access from seat to bunk.

Look here! The curved edge of the wider, lower grille opening gives the K200 a distinctive look befitting a premium model which marks the start of a new era for the long-serving K-series. Behind the grille though are considerable gains in cooling efficiency.

So, having driven many different K-series models over the past 30 years and more in everything from express linehaul to roadtrain triples, these driver factors were the main motivation for jumping at an offer to pilot a K200 on a day-long drive through the Victorian backblocks in the company of Kenworth sales manager Rob Griffin. In effect, it was an assessment of environment and ergonomics rather than performance, and the fact that the truck was coupled to a partially loaded single trailer rather than a B-double set was of little importance.

The demo truck was a full production unit which had already covered 11,000 km on trial duties and as a showpiece for the new series was well endowed with all the latest options, not least the full suite of safety features from Kenworth’s (Knorr Bremse) electronic brake safety system (EBSS) including anti-lock brakes, electronic stability program and what Kenworth calls ‘active cruise with brakes’, or ACB. Like most modern active cruise control systems, ACB monitors traffic ahead of the vehicle and on detecting a potential collision has the ‘smarts’ to automatically apply the truck’s foundation brakes after first applying the engine brake and reducing the throttle.

Built on a 4.28 metre wheelbase and fitted with the 2.3 metre Aerodyne sleeper cab, the test truck was punched by a Cummins ISX engine rated at 525 hp, putting the power to the ground through a Dana D46-170 drive tandem running a 4.3:1 final drive ratio, mounted on Kenworth’s Airglide 460 airbag rear suspension.

The transmission was Eaton’s super-slick Ultrashift-Plus automated 18-speed overdrive and while shifters don’t come much sweeter than this latest evolution of Eaton automation, in this instance it was a disappointment … not because of any deficiency or fault with the transmission, but simply that its manual counterpart would have better highlighted the K200’s unquestionable gains in space and function. As it was, the automated shifter’s Cobra control tower was a somewhat lumpy affair mounted on the forward edge of the engine cowl and consumed more space than seemed necessary.

In fact, climbing behind the wheel of a manual model for a few minutes, it was instantly evident that the stick shift with its innovative and simple ability to be folded out of the way provided a notably easier move from the seat than the automated version. Consequently, a Cobra controller integrated into the fascia on the driver’s left would be an obvious and significant improvement on the arrangement in the demo truck. Simply stated, Kenworth can do better.

Still, in either automated or manual form, the swing out of the driver’s seat in the K200 is massively improved over its predecessors. Lightyears ahead!
Likewise, the lower floor height over the engine is a remarkable achievement which allows drivers up to six feet tall to stand fully upright. And this, combined with immeasurably easier access to and from the seat, effectively silences complaints which have hammered at Kenworth’s door for decades.

Speaking of silence, interior noise levels in the K200 are exceptionally low and Kenworth’s work on reducing noise and heat intrusion appears to have paid off … big time!

As for actually climbing in and out of the cab, the revised step arrangements are notable improvements. The K200 is a tall truck but the steps are evenly spaced and provide sure-footed access with conveniently sited grab rails for support. On the passenger side though, the ease and safety of entry and exit are diminished by the surprising absence of a grab handle on the inside of the A-pillar.

In on-road terms, the K200 behaved brilliantly. Steering and ride quality were exemplary while forward vision through the optional one-piece windscreen was superb. Sure, most operators will probably see the

single sheet as an expensive piece of replacement glass compared to the standard split ‘screen, and of course they’d be right. Similarly though, there’s no question the vision provided by the one piece of glass is exceptional.

Likewise, modified doors coupled with superbly sized and mounted side mirrors deliver an excellent view of ‘the back door’.

For the most part, the dash and switchgear layouts have undergone only minor amendments but there are nonetheless a couple of concessions to modern practice, specifically a switch on the far right of the main dash for regeneration of the diesel particulate filter. What’s more, engine brake controls in the demo unit were via a switch on the left fascia rather than on a thin wand atop the steering column. According to Kenworth, the change to the dash-mounted switch becomes necessary when the suite of safety features is installed.

So all up, the K200 is a major and unequivocal advance on its forebears and while the most important and obvious gains are in the space and convenience afforded by a comprehensive rework of the engine tunnel and floor area along with effective innovations like a collapsible gearlever, it’s more about the complete package than individual elements.
External appearance, of course, is the most striking element of the new model but on the inside there are also numerous nuances in trims, fittings and features which all add to a truck which has taken a generational leap into the modern world.

Sure, there are perhaps other cab-over brands with rights to claim easier access and better internal space and convenience, but given the established acceptance of the K-series built on its long-standing reputation for durability and operational efficiency, the substantial gains achieved by Kenworth engineers are immensely valuable.

In fact, when it’s considered that Kenworth’s cab-over has design roots tracing back 40 years, the advances contained in the K200 are nothing less than exceptional.




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