Test Drive: Kenworth’s T680 with integrated 52-inch sleeper

By on November 13, 2013
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When Kenworth offered me the opportunity to put its T680 tractor with the new 52-inch integrated sleeper through its paces, I jumped at the chance. Kenworth had invested more than $400 million over nearly five years to develop the T680. Introduced in early 2012, it is the most aerodynamic truck in the company’s 90-year history.

Designed to slice smoothly through the air, the T680 has earned the U.S. EPA SmartWay designation (SmartWay is the agency’s service mark that designates the cleanest, most fuel-efficient vehicles) and was named the 2013 Heavy Duty Commercial Truck of the Year by the American Truck Dealers.  But what made the invitation even more appealing was that I would also get to drive Kenworth’s new cabover models. As you long-time readers know, I love cabovers. Hence my nickname, “Cabover Kolman.”

All aboard

I picked up the rig at the Paccar Technical Center in Mount Vernon, Wash. The tractor I would drive had a proprietary 12.9-liter Paccar MX-13 diesel rated at 455 hp and 1,650 lb-ft of torque with an integrated MX engine retarder, paired to an Eaton Fuller 10-speed transmission. It had wide-base tires and was coupled to a loaded van trailer.

The MX-13, with its high pressure common rail system and lightweight fuel-efficient design, is the standard powerplant for the T680. The engine is rated up to 500 hp and 1,850 lb-ft.

Two things jumped out as I approached the rig. One was this T680’s unique color: Oro Adonis. The other was the large, stylish, signature Kenworth grille that is manufactured from corrosion-resistant aluminum wire mesh.

Climbing into the T680 was effortless due to a user-friendly step and grab handle configuration and a new, larger, lightweight and more durable door design that opens 30 percent wider than past models. A pressure relief valve equalizes interior and exterior air pressure to make the door, which is tripled sealed against the elements and road noise, easy to open and close.

Productive work environment

Settling into the driver’s seat, I was struck by the roominess of the 83-inch-wide stamped aluminum cab. An all-new seat design and air-suspension system automatically adjusts to the driver’s weight. Plus, the seat has an assortment of adjustments. All that, combined with a new tilt and telescoping steering wheel, will enable pretty much any driver to find a comfortable driving position.

Also impressive is the panoramic, one-piece, bonded-in windshield, which is 50 percent larger than other Kenworth models. The windshield, along with the deep side windows, provide superior visibility. Visibility is of utmost importance as research shows that 90 percent of all driving decisions are based on vision alone.

The dash and controls are thoughtfully laid out and ergonomically designed. The new dash cluster has an easy-to-read layout with nine standard gauges and 12 additional gauges available. A thoughtful touch is the new switches which utilize a toggling feature yet maintain rocker switch functionality.

The all-new Driver Performance Center (DPC) has a full-color, high-resolution, 5-inch display screen that includes current truck information, diagnostic data and pop-up alerts. Included in the dash is the Kenworth NavPlus, with truck-specific navigation, roadside assistance, vehicle data, hands-free phoning and audio controls, including satellite radio, AM/FM/CD/MP3/USB/Bluetooth.

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Kohlman with the Kenworth

Roomy sleeper area

Not having spent much time in a mid-roof sleeper, I was pleasantly surprised by the roominess of the T680’s 52-inch sleeper cab. It is a spacious 83 inches wide with a comfortable 23 inches of room between the seats for effortless sleeper ingress and egress. There was enough headroom height for me — at 6-foot-4 — to stand straight up between the seats.

The standard liftable bunk with its underneath storage and upper storage units on the sleeper’s back wall provide ample space to hang clothes and store items. The separate sleeper control panel, with the HVAC, audio and light controls, are nicely situated. The 38-inch-wide mattress offered plenty of room to stretch out and was surprisingly comfortable.

In talking with Kenworth engineers, I learned that the 52-inch sleeper offers up to approximately 600 pounds in weight savings compared to the 76-inch integrated sleeper available with the T680, which also comes in a day cab version.

Engine compartment

Doing the engine compartment pre-trip check was easy. With the advanced hood assist system, lifting the hood requires about 35 pounds of opening force, according to Kenworth engineers. There’s no need to brace one’s self with a leg on the bumper for added pull-open support.

The hood closed without difficulty as well. All daily checks were easily accessible.

To the streets

So much for the inside. Let’s move on to how the T680 52-inch sleeper handled and rode. Let me just say it was difficult to get the smile off my face.

The MX-13 had plenty of horsepower, torque and acceleration. Shifting was easy, thanks in part to a new clutch that features a hydraulic-assist that reduces the amount of force needed to depress the clutch.

Another considerate touch is the repositioned throttle that makes for a more comfortable driving position. That’s a bonus when behind the wheel for long periods of time.

I came to appreciate the Driver Performance Center, which sits in the dashboard centered above the tachometer and speedometer. It provides real-time information on fuel, vehicle and safety systems. A driver can get, at a glance, information about operating in the sweet spot between performance and efficiency. I found myself continually trying to best my mpg “score.”

I was well into my drive when I realized that something was lacking — noise and vibration. The T680 is unusually quiet, especially with the windows closed. When designing the T680, Kenworth made cab interior quietness a major focus. Sound-dampening materials and designs were incorporated from the outset and the results are impressive.

When I finally returned to the Paccar Technical Center, I felt less fatigued and, dare I say, more fulfilled. It was a most enjoyable day of trucking.

Now about those cabovers …

When Kenworth invited me to drive its new cabovers, I assumed they would be heavy duty COEs. Not so. They were medium duty Kenworth K270s and K370s. Introduced earlier this year, these models are designed expressly for the North American market, built on a North American chassis very similar to Kenworth’s conventional medium duty trucks: the T270 and the T370. The previous K270s and K370s were adapted from European models.

I put the new cabovers, which had 6.7-liter Paccar PX-7 diesels — from 200 to 360 hp and 520 to 800 lb-ft torque — mated with automatic transmissions, through their paces on the Paccar Technical Center’s high-speed and durability tracks, plus ran city streets and highways. Even loaded, there was plenty of power, acceleration and torque.

The 2,500-sq-in wraparound windshield and extra-large side windows afford great  visibility. The 55-degree wheel cut enables a tighter turning radius and greater maneuverability. A comfortable, quiet cab with a curved dashboard presents gauges and switches in a logical layout that is easy to view and reach. The trucks were a hoot to drive.

About David A. Kolman

David A. Kolman, an over-the-road driver for many years, is the Senior Editor of Road King magazine.

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