Peterbilt reveals major redesign of flagship Class 8 Model 579

Practically everything trending in trucking finds its way into redesign

The redesign of Peterbilt Motors Co. on-highway flagship Model 579 took five years and input from 59 customers to apply what matters most to drivers and fleets.

The PACCAR Inc. (NASDAQ: PCAR) division unveiled the makeover of the Model 579 on YouTube on Wednesday.

For starters, the aerodynamic shape of the new 579 took more than 1,000 hours of computational fluid dynamics analysis and 7.8 million hours of computer processing. The resulting 7% improvement in fuel economy translates to $2,000 in annual savings over a comparably equipped current Model 579, according to Peterbilt General Manager Jason Skoog. 

A new, stronger Metton hood is narrower and more resistant to damage. It covers the new 2021 PACCAR MX-13 and MX-11 engines and PACCAR transmission. The homemade engines account for about 60% of Peterbilt and Kenworth powertrains. That’s compared to 30% a decade ago, PACCAR CEO Preston Feight said this week.

Product enhancements

Peterbilt calls the thoroughly redesigned 579 the most technologically advanced and reliable truck it has built. The Model 579 was introduced in 2012. Among the truck’s new features:

  • A new three-piece bumper integrates the forward radar cover for collision mitigation. A larger aerodynamic air dam protects against damage and lowers replacement costs. 
  • Improved aero mirrors, fairings, side skirts and closeouts help the truck’s aerodynamic shape. A revised A-pillar vane redirects airflow around the windshield,. That reduces friction and helps lower cabin and sleeper noise by 10%.
  • A 15-inch digital dash display delivers information in a clean, intuitive interface. A smart steering wheel with customizable and easy-to-use controls fine tunes information from 30 sources. A driver chooses what is displayed. All Peterbilt Class 8 trucks will get the new display standard, Skoog said.
  • Before departing on a trip, the digital display can run a visual inspection of 13 systems, showing a green checkmark with each passed test. Post-trip, a detailed trip information screen shows a breakdown of important metrics from the most recent journey.
  • Small interior additions include a fixed cup holder. Multiple USB charging ports in the center console are optional.
  • The Bendix Fusion Driver Assistance Systems has integrated camera and radar technology that enables collision mitigation, overspeed alerts, lane departure warning and lane keeping assist. 
  • The 579 UltraLoft introduced in 2018 is an integral sleeper with 70 cubic feet of storage space and an 8-foot-high ceiling. The cabin has room for small appliances, including a 1.1-cubic-foot  microwave, a 32-inch TV, a tall wardrobe closet, multiple power outlets and optional bunk beds with a fold-away ladder. Multiple windows provide natural light and additional ventilation.

Texas assembly

Validation units have accumulated 1.5 million real-world miles. The truck will be built at Peterbilt’s plant in Denton, Texas, which Skoog said has received $140 million in upgrades over the last five years.

“This new product is the result of five years of relentless focus on increasing fuel economy, taking driver comfort to new heights and maximizing uptime,” Skoog said. 

“The clear and precise information relayed to drivers through the Peterbilt digital display, combined with the advanced safety systems found throughout the truck, provide a much higher level of awareness of the truck and its surroundings.”   

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Alan Adler

Alan Adler is a Detroit-based award-winning journalist who worked for The Associated Press, the Detroit Free Press and most recently as Detroit Bureau Chief for He also spent two decades in domestic and international media relations and executive communications with General Motors.