Peterbilt’s new Model 579 blends need for economy with sleek styling
Photos by Brian Blevins, Story by Jack Roberts
For the better part of the past decade or so, many truck and engine manufacturers’ engineering resources and research and development dollars have been spent meeting the strict 2010 EPA diesel emissions mandates. That’s not to say truck manufacturers — including Peterbilt —haven’t made continual upgrades to their existing vehicles. But the emphasis has been on emissions technology.
This is Peterbilt’s first all-new chassis and cab in 13 years and the sixth model to join the company’s stable of trucks. Andy Weiblen, the 579’s engineering manager, says the new truck takes everything that has happened to heavy-duty trucks during that time and turns it into a highly integrated technological marvel. Everything about the new truck was designed to make life easier and more productive for fleets, owner-operators and drivers. Advancements range from anti-idling solutions to simplified instrumentation to a new, optimized dash layout to the new Evolution driver’s seat.
The 579 is the sleekest, cleanest overall tractor design in Peterbilt’s history.
Weiblen says the five-year development cycle for the new truck was driven by the most intensive market/driver/fleet research ever conducted by Peterbilt. “One of our market surveys was to take a fully adjustable truck cab and sleeper to truck stops all around the country,” he says. “We invited drivers into the cab and sleeper and asked them to set any component in the mock-up exactly where they would want it if they were designing their own personal vehicles.”
Drivers could adjust armrests, pedals, interior cab width or seat positions — to name a few. The result, Weiblen says, was a database of thousands of real-world ergonomic data. “And we were able to use that information to design a truck that is remarkably comfortable for a wide range of drivers.”
The first thing that strikes you when inspecting this truck is how sleek the frontal design is. Erik Binns, on-highway marketing manager for Peterbilt notes that the company has been in transition over the past decade as aerodynamics have come to the forefront in fuel economy technology. But Peterbilt’s legacy was built with large, powerful, flat-nosed conventional tractors. “I wouldn’t say there’s been resistance, exactly, to our move toward aerodynamic vehicles,” Binns says. “But there’s a heritage there that appeals strongly to our customers. So we have a responsibility to honor that heritage in a way that says, ‘This is a Peterbilt,’ while giving our customers that absolute latest in modern design and technology to help them compete in the real world. It can be a challenge.”
If the 579 looks somehow smaller and more compact than most Class 8 tractors, it’s because this is the sleekest, cleanest overall tractor design in Peterbilt’s history. The nose on the new truck is 2 inches lower than anything else the company offers. And every sharp or flat edge has been rounded or smoothed off to facilitate airflow over, around and under the truck. The front windshield is higher and blends seamlessly into an air dam above the cab. The A pillars are noticeably thinner — optimizing both visibility and airflow — while details such as the cab marker lights were subjected to air-fluidity dynamics testing to achieve the ideal location and help the truck cut efficiently through the air.
Peterbilt will offer the SmartWay-certified Model 579 in a variety of aerodynamic configurations, from a base model to a California Air Resources Board-legal version to the full aerodynamic package, which Weiblen says delivers between 8 percent and 10 percent better aerodynamics than comparable models — which translates into a 4 percent to 5 percent boost in fuel economy.
Given the investment in recent engine technology, the 579 will be offered with Peterbilt’s powertrain offerings, including Paccar MX and Cummins ISX diesel engines and Eaton automated and manual transmissions. Peterbilt has developed a new clutch for use with manual gearboxes on the 579, notable for its extremely easy engagement pressures. Most clutches today take about 55 pounds of down-pressure to actuate. But the new Peterbilt clutch only requires about 30 pounds of down-force — a tremendous difference for a driver dealing with heavy, stop-and-go traffic in Dallas and Fort Worth.
The Evolution premier driver’s seat grabs your attention — before you even climb into the cab. You can hit a large button that automatically deflates the seat down to the floorboard for easier entry and exit from the cab. Once you’re in the seat, simply hit the same button again and the seat automatically returns to your preset drive height. Another large toggle switch close to the height button allows drivers to instantly adjust seat compression to deal with a rough patch of road.
Once behind the wheel with the 13-liter MX engine ticking over, the next thing that struck me was the elegantly functional dash layout. If you feel truck dashes are getting a bit busy these days with all the engine information, entertainment options and navigation systems, you’ll like the 579’s interior design. Weiblen says simplicity was the overriding design criteria for this entire cab and sleeper and the dashboard is proof of that. Large, easy-to-read, softly backlit dials are accented by bold chrome bezels. Even better, stereo, HVAC and navigation systems have been simplified to make them easier — and safer — to operate. One nice touch is the automatic thermostat, which blends the air inside the cab and sleeper to hold a preset temperature all day long.
Views from the driver seat are outstanding thanks to the lower nose, taller front windshield and smaller A pillars. Designers also expanded the side windows and optimized rear-view mirror placement. The new mirrors minimize drag penalty on the overall vehicle aerodynamics while offering clear rear views.
The dash is part of a much cleaner, more compact design, which Weiblen says helps create an easy flow within the sleeper. You can easily move from the driver’s seat to the sleeper without catching your knee on a cup holder or snagging your pants on a gear-shift lever. And in the rear, drivers tired after a long day will find a sleeper outfitted with the latest in comfort technology – from a work station and hook-ups for flat-screen TVs, laptops and video game consoles to lots of optimized storage space.
Our route takes us in a big circle past the Texas Motor Speedway before winding up back in Denton. It’s a good mix of two-lane roads and interstate driving, with sections of heavy traffic and even a few hills. There’s a bit of bad luck, though: It seems my test rig is also a show truck and will be leaving for a big industry trade show in Louisville, Ky., later in the day. And because everything on the truck — including its fifth wheel — is chromed out, polished and ready to dazzle truckers from around the country, hooking a trailer up is a no-no. This time around, anyway. But even driving bobtail will give me a good chance to see for myself where the bulk of the Model 579’s enhancements are: in the cab, sleeper and chassis.
Driver safety and awareness systems are among the countless technologies designed into this tractor. So I spend a good portion of our drive using theBendix Wingman adaptive cruise control feature, which radar-tracks four-wheelers in front of the tractor and either holds my preset cruise speed or automatically adjusts it to deal with a slower-moving traffic. It’s an incredibly well-designed and useful feature.
The 579 is an extremely quiet and comfortable truck. The new Evolution seat is not only wider than most seats, but it features numerous lumbar settings ensuring a comfortable ride in just about any road condition. Combine that with the new telescoping-tilt steering wheel, and you feel more like you’re behind the wheel of a sports car than a Class 8 tractor at times.
Weiblen says the 579 engineering team used the latest composites and ride-dampening technology on the truck cab. A particular emphasis was placed on eliminating noise and vibrations in the cab. As quiet as the truck is at rest, it’s amazingly quiet even at full-throttle highway speeds. Again, the overall design has a lot to do with this. But consider also the truck’s aerodynamic design virtually eliminates exterior wind noise buffeting over the cab. You can roll the windows down at 65 mph and still carry on a normal conversation with your passenger. With the windows up, interior noise levels in the 579 are approximately 69 decibels — and those levels don’t rise much at all with the windows down.
An all-new chassis and cab suspension make this a fine-tuned truck. Weiblen and his team have taken almost all the lateral sway out of the equation, making for sure-footed handling. The truck doesn’t wander around its lane at highway speeds — even with an occasional blast of wind. The clean aerodynamics contributes by making the truck feel one with the road. This just isn’t a truck that’s going to shake or vibrate its drivers during the course of a day.
Peterbilt is taking 579 orders now, with the first production trucks likely to arrive at fleets and dealerships by late summer. The new truck is a fine addition to Peterbilt’s overall lineup and one that fuel conscious fleets and owner-operators will want to consider as fuel prices continue to rise. Peterbilt knows that aerodynamics and styling are not mutually exclusive factors when it comes to designing a dependable and productive truck.
Peterbilt Model 579 test vehicle specs
Engine: PACCAR MX13 diesel
Horsepower: 455 hp at 1,900 rpm
Torque: 1,650 lb.-ft. at 1,100 rpm
Transmission: Eaton-Fuller UltraShift Plus automated manual
Cab configuration: Aerodynamic 123-inch BBC/63-inch hi-rise sleeper
Front Axle: Dan Spicer E1202I rated at 12,000 pounds
Front brakes: Dana Spicer Air Disc
Rear Axle: Meritor RT-40145A rated at 40,000 pounds
Rear Brakes: Bendix 16.5-by-7 cam drum
Rear axle ratio: 3:07
Full Model 579 Aerodynamics Package
SmartSound Cab Insulation Package
Bendix Wingman Adaptive Cruise Control
Bendix Electronic Stability Control System
Affected trucks include model year 2008-2018 Freightliner Cascadia and Western Star 4700, 4900, 5700 and 6900 trucks. DTNA says after hard brake applications, the brake light pressure switch may not activate the brake lights with the light application of the brake pedal.