Kenworth K200

The requirements of the Australian truck market have changed considerably over the last 40 years, since Kenworths started building trucks in Bayswater on the outskirts of Melbourne. One model has continued throughout those 40 years, the K 100. Over time the truck has been developed and evolved to meet the needs of the Australian trucking operator. New technologies have come along, horsepower expectations have risen dramatically, GCM requirements continually rise and driver comfort expectations have increased considerably.

With the introduction of a new model for the 2011 Kenworth Range, the company has made what, for them, are quite radical changes. The large rectangular radiator grille on the front of the cabover has been the signature of the K 100 since day one. Every emission regulation change in recent years has increased the need for engine cooling. Radiators have grown in size and airflow through the engine compartment has become a critical component in truck design.

Rule changes for B-doubles saw their maximum length extend from 25 to 26 metres. Limitations on trailer lengths, at the same time, meant it became possible to increase cab size and, therefore, interior space for the driver. The living space for linehaul and interstate drivers could be expanded and a number of more spacious models became viable for sale on the Australian market, a number of models were developed to fill the gap.

As a result of these changes, Kenworth has come up with the K 200. Without interfering with the core values of the model, which have made it the top-selling cab for many years, the company has come up with a model that can be described as a 21st-century Australian truck. The need for cool air has seen the radiator grille go from rectangular to oval, the engine has moved rearwards and the cab has been raised. Design changes have created a cabin interior in which the driver can walk around with ease.

The impact of these changes probably justifies the change in model classification from K 100 to K 200. Not only does the truck look radically different from the outside, while retaining that classic K 100 shape, it is also radically different on the inside. For the driver, there is much more usable space.

Prime Mover had the opportunity to take this new truck for its first press test drive from Canberra, down the Monaro Highway to join the Princes Highway, through to Melbourne and the home of Kenworth. Pulling a single trailer, this was not a test of how well the driveline can handle high GCM work but more of a chance to assess the impact of the changes to the design of the truck on life for the driver.

Anyone familiar with driving a K 100 in the past will have certain expectations about the driving experience. Climbing into the K 200, it is clear from the outset this is definitely a very different truck. Settling into the relocated driver’s seat gives an impression of the improved visibility and ergonomics of the new model. It is surprising how effective a small change in the geography of the cabin can be in improving the feel for the driver.

In some ways, this is a familiar driveline with a Cummins ISX rated at 550hp (410kW) putting out 1850 ft lb (2500Nm) of torque. This drives through an Eaton gearbox to a Meritor rear end. This is a very familiar engine to the Australian truck buyer and has proved its worth in recent years. Changes in the engine for 2011 are relatively minor although a Diesel Particulate Filter (DPF) has been added to the exhaust stream.

However, although the 18 speed Eaton transmission is familiar, its control system is not. This is the new generation of AMTs from Eaton, the Ultrashift Plus. Introduction of this new AMT is a major generational change for the US gearbox manufacturer. The functionality of the new gearbox brings it up to a new level of performance. This can now be compared with the kind of AMT we have been seeing fitted by the Europeans for nearly a decade.

Out on the highway, the combination of the torquey and reliable ISX with an intelligent and flexible AMT makes life easy for the driver. In a full day’s drive through undulating country and a couple of difficult situations, this driver never felt the need to intervene manually with the way the transmission was going about its job. If a change up or down is required, the control systems of the gearbox are sensitive enough to inputs, by the right foot on the accelerator, to get the message.

For a driver who doesn’t have to be concerned about ensuring the truck is in the right gear, or even intervening with the autobox, it’s possible to consider the other changes to the K 200 and their effects. The most obvious improvement is in the ride. This truck uses the same cab mounts and the same front suspension used in its predecessor but adjustments in the geometry of the whole vehicle, including moving the engine rearwards, have had their effect. In situations where a driver could have felt knocked about in the past, the new K 200 sails through relatively smoothly.

Analysing the performance of a truck in this situation, where some changes have been made but not to components directly affecting the ride, is all about perception. It would appear the better performance of this cabin is as a result of a combination of a large number of small changes. The driver’s seat position is much better in relation to the steering wheel, the dashboard, the door and the roof. Couple this with moving some mass, in the form of the engine, back from the front axle and the result has given Kenworth a significant dividend.
The new design of the K 200 has also given Kenworth the chance to catch up with their closest competitors in terms of the usability of the driver accommodation. By raising the cab it is now possible to walk from the driver’s seat into the middle of the cab and stand upright. The flat top to the engine cover is approximately 150mm higher than the floor under the driver’s seat. This flat floor makes it possible for the driver to walk around the sleeper.

For manual models, the gear lever can be folded back to make access from the driver’s seat even easier. On this test, with and Ultrashift Plus fitted, the Cobra shifting control is fitted to the dash and does not constitute much of an obstacle to the driver shifting out of their seat into the middle of the cabin. It is surprising how much roomier the cab feels now that it is possible to walk about in it.

The model on test was the 2.3m standard size sleeper cab and an inspection of the larger 2.8m version demonstrates just how much extra room is now available for driver accommodation. The comfort levels available now from the K 200 match those formerly available only on conventional trucks in the Kenworth range. This new cab design alone makes the performance of the K 200 a game changer.

The innovations available in this test truck do not just end with the redesign of the truck and cabin. This K 200 is also fitted with the latest electronic safety technology available from Kenworth, the EBSS. Incorporating electronic braking, active cruise control and stability control, this system is another way in which this new model can match options available on competing European trucks.

The EBSS system will intervene if it detects the truck operating in such a way that safety is compromised. For the purposes of this test the active cruise control was set to ensure vehicles in front of the truck were travelling at least three seconds in front. The system, whether on or off, gives a constant readout to show just how far away any vehicle in front of the truck is.

The system is calibrated to respond only if the vehicle is getting closer to the truck. This means that when an overtaking vehicle moves back in front of the truck, closer than three seconds but moving away, the system is activated. The system is only activated when the truck is closing on the vehicle and it comes into that three second range.

The system’s first reaction is to slow down using reduced engine revs. If the vehicle in front still gets closer again, the engine brake is engaged and this is sufficient for most situations. However, when vehicles in front of the truck pull up sharply, the system can resort to proportional service braking to keep the truck out of trouble.

On the Princes Highway, coming into a small town, a group of cars in front of the truck slowed as they entered the 80km/h zone and the truck did likewise, changing down a couple of gears. Then one of the cars stopped rather abruptly causing the queue to hit their brakes. The active cruise control system reacted immediately to the deceleration and engaged some service brakes. It was then up to the driver to break more fully and bring the truck to a halt but the swift reaction of the ACC took all of the risk out of the incident.


The stability control system will also intervene, killing the engine and bringing in the engine brake, if it detects any risk of a rollover. Further stability control is available through the EBS system, braking individual wheels to try and keep the combination running true and avoiding jack knifing or rolling over on a slippery surface.

Some of the more traditional truck drivers may find this kind of interference in their control of the truck uncomfortable. However, on the evidence of just one day’s driving and not in a situation of rushing to meet a deadline, the swift action of the ACC during one incident proved the value of the entire system and its effectiveness in aiding the driver to be even safer.
A small issue, which became apparent after the release of the initial prototype vehicles last year, was that of accessible storage for the driver from the driver’s seat. The original design has a large locker on the top of the central dashboard and this has now been augmented by a unit, capable of holding two drinks and assorted odds and ends, fitted low down at the rear of the central binnacle.

The overall experience of the driver in the cabin is also improved by the way the noise, air and heat is handled in the engine compartment. With a lower floor and improved noise proofing, normal conversation inside the cabin is much easier. The flat floor also has cool air flowing through specially designed ducts under the floor. The overall effect is of a much more pleasant environment for the driver.

The Kenworth K Series has become the standard truck, central to the Australian trucking industry. As such, it has to suit the preferences of a large number of trucking operators and an even larger number of truck drivers. Questions are asked of this truck more than they are of any of its competitors. Industry expects Kenworths to deliver the kind of truck it needs, and especially as a B-double prime mover.

What the industry needs has changed considerably in recent years, not just in terms of exhaust emission legal requirements and power available but also in terms of driver comfort and space as well as meeting ever higher safety standards. The question on the trucking industry’s lips in recent years is whether Kenworth can adapt and meet these new challenges. On the evidence of this one-day road test of the new K 200, it is clear they have answered their critics and set the bar even higher for the competition to meet.


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