Aero encore

The optional folding armrests allow easier access to the sleeper.

Kenworth launched the T600 in 1985, when its aerodynamic styling was both new and somewhat revolutionary. Its successor – the new T660 – hit full production last fall. Kenworth says it uses less fuel even than the T600, mostly due to cutting-edge aerodynamics.

A Kenworth drive test afforded me the opportunity to test two differently spec’d T660s. At Paccar’s Technology Center near Seattle, I climbed into a silver pearl T660 Aerocab with an 86-inch sleeper and Pendleton interior, pulling a fully loaded dry van. The power plant was a 475-horsepower Cater-pillar C15 with 1,650 lb.-ft. torque, hooked to an Eaton 13-speed Ultrashift fully automatic transmission leading to 3.55 Dana DSP40 drive axles and Bridge-stone 295/75R22.5 tires.

I was southbound on I-5 when snow reduced visibility to less than 100 feet. The roads were too warm to freeze, so I continued south, albeit well below the speed limit. Turning around at Exit 215, I overshot the left turn onto the northbound entrance ramp by a few feet. While making the hard left, I found that the T660 cuts a sharp turn if necessary. I expected the front wheels to reach the paved shoulder, but the last turn of the steering wheel brought the T660’s front end around sharply, and the truck entered the ramp with all wheels between the sidelines.

I pulled over for a map check, then drove north and got off at Exit 221. After missing a turn that wasn’t on the map, I ended up on state Highway 532 westbound until spotting a turnaround opportunity in a country-club parking lot. The T660 politely idled in, smartly pivoted 180 degrees on its trailer tandems and rolled back out onto the highway.

When you miss a turn, it helps to be in a truck that minimizes the consequences of your error. The 660’s defroster melts snow off the windshield; it has good wipers and mirror heaters for maximum visibility; it has sure-footed maneuverability in close quarters, especially when fully loaded; it’s responsive in suburban traffic; and it has a tight turning radius.

My next highway test-drive was a T660, also silver pearl, but with a 72-inch sleeper and a 500-hp Cummins ISX, making 1,650 lb.-ft. of torque coupled to an Eaton 14-speed Ultrashift. This route was simpler: all on state Highway 20, a twisty, two-lane road that approaches the coast. Maneuverability, visibility and responsiveness were in demand, and a well-designed truck made this work easier.

This T660 had Kenworth’s new Clean Power auxiliary power unit, introduced at the Mid-America Trucking Show in March. John Duffy, who helped design it, rode along. Kenworth powers its APUs with four extra deep-cycle batteries, a progressive move given the evolving environment for idling alternatives. Not only do most current APUs require diesel, but exhaust from diesel APUs soon will be regulated by the U.S. Environmental Protection Agency, Duffy says. The resulting mandatory modifications likely will make diesel APUs more expensive.

The Clean Power APU, mounted beneath the bunk, can cool the sleeper to 75 degrees for up to 10 hours, even with the television, refrigerator and coffee maker in use, Duffy says. Both the lower and upper folding bunks have Clean Power controls. Cut-off switches prevent it from draining too much power from the batteries; the deep-cycle batteries recharge to full strength when the engine is running. Kenworth also insulated the cab and replaced standard interior incandescent bulbs with power-saving LEDs, which Duffy says is a first in the industry.

With the Clean Power APU to accompany the 660’s aerodynamics, as well as a roomy, almost luxurious interior, a premium-spec’d T660 is one of the better places to be – for comfort and for an owner-operator’s bottom line.

The Pendleton interior looks refined, yet sturdy. It offers wood grain dash panels, slate-gray, diamond-tufted carpet and button-down upholstery, and brown leather door pads, sofa bed, seats and armrests. The seats are heated with multiple controls. When vertical, the armrests fold behind the seat backs for a wider walkway.

The cavernous sleeper promises comfort, whether parked or rolling. The sofa bed has twice a single bunk’s width: just big enough for two, although there’s a folding upper bunk. Both bunks have clock, light and temperature controls. There’s plenty of cabinet and under-bunk storage, and the big shelves on both sides, up high with 3-inch retaining risers, looked particularly roomy, secure and handy. The sleeper windows double as emergency exits, and when the truck is rolling, snow won’t come through the open sunroof.

The cab’s fine-tuned ease of operation shows Kenworth’s big-truck experience. Dash gauges are numerous, but organized, easy to read and, due to simplified, more rugged dash wiring, more reliable. Driver storage compartments are secure and accessible, the adjustable steering column has a position for every driver, and dash controls, including the GPS, are within easy reach.

The T660’s sloped, aerodynamic hood is designed to reduce drag and to increase visibility. The lower drag will improve fuel economy, one of many readouts available through a multi-function digital display that provides onboard diagnostics. There’s also a gear display, which comes in handy with an automatic transmission.

TRACTOR: 86-inch Studio Aerocab with Pendleton interior
ENGINE: 2007 Caterpillar C15, 475 hp, 1,650 lbs.-ft torque
TRANSMISSION: Eaton 13-speed Ultrashift
FRONT AXLE: Dana Spicer E-1202I
FRONT SUSPENSION: Taper leaf with shock absorbers
REAR SUSPENSION: Kenworth AG380 52-inch spread
FRONT BRAKES: Bendix Air Disc
REAR BRAKES: Bendix ES S-Cam 16.5 X 7 dual
FRONT TIRES: Bridgestone R287 295/75R22.5
REAR TIRES: Bridgestone M720FE 295/75R22.5
BATTERIES: Paccar 2800cca dual purpose
ALTERNATOR: Paccar brushless 130-amp
STARTER: Paccar 105P 12-volt
COMPRESSOR: Caterpillar 270 16.1 cubic feet per minute
FUEL TANKS: 120-gallon polished aluminum
WHEELBASE: 240 inches

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