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57X Efficiency

Tested in a tunnel, proven on the road.

Extensive wind tunnel testing enabled our engineers and designers to create a sleek, modern chassis with bold aerodynamics that help deliver maximum fuel efficiency in all conditions and at any speed. Nothing escaped scrutiny.



  • Redesigned hood and door mirrors for enhanced aerodynamics
  • Full chassis fairings featuring enhanced flexible side skirts
  • Reshaped front wheel well closeouts
  • 24” side extenders
  • Optimized low ground clearance bumper
  • Optimized drive wheel fairings
  • Extended roof spoiler
  • Aerodynamic height control
  • Michelin X Line Energy D+ Tires



Front Bumper

Two-piece painted bumper with integrated air ducts improves aerodynamics.

Wheel Fairings and Covers

Optimized drive wheel fairings and FlowBelow wheel covers reduce drag and improved fuel economy.

Side Fairings

Chassis side fairings with black flexible skirts improve aerodynamics while shielding tanks and batteries from the elements.

Side Extenders

24" side extenders with black flexible ends offering greater aerodynamics and longer life.

Exterior Lighting

All the lighting on the 57X is LED, providing bright light with reduced maintenance and downtime for replacement.

Available Engines


The DD13 engine offers the best of the best in cutting-edge diesel engine technology and engineering. It's been significantly redesigned with drivers in mind, with numerous innovations to increase performance, durability and productivity.

  • Horsepower 370-525 HP
  • Torque Range 1,250-1,850 lb-ft.
  • Displacement 12.8 L


Backed by years of proven performance, the new Detroit DD15 takes reliability, durability and productivity to the next level. Perfect for any operation, vocational or on-highway, the DD15 delivers everything you need from an engine, including greater profitability.

  • Horsepower 425-505 HP
  • Torque Range 1,550-1,850 lb-ft.
  • Displacement 14.8 L

Detroit Dd16

The biggest, toughest and most powerful engine Detroit has ever produced, the DD16® is the only 16-liter engine available. And since it offers the longest service intervals in the industry, it tackles your hardest jobs while increasing uptime and profitability.

  • Horsepower 500-600 HP
  • Torque Range 1,850-2,050 lb-ft.
  • Displacement 15.6 L

Western Star provides a wide range of new vehicle engines compliant with EPA, CARB emissions, GHG, and OBD requirements.

Please consult your local dealer to ensure the selection of a product that meets your specific needs.



The latest and greatest highway truck from Western Star deserves the latest and greatest powertrain options from our partners, and that starts with Detroit. From the new versions of the Detroit® DD13® and DD15® engines, to the proven DD16®, to the newest DT12® automated manual transmission, you’ll have the power you can count on.


Integrated Detroit® Powertrain

The Integrated Detroit® Powertrain is the most fuel-efficient combination of Detroit® components available. Designed to work together to deliver maximum performance and lower operational costs, its list of advanced features include Intelligent Powertrain Management (IPM6) - the next level of predictive technology with the Detroit® DT12® transmission - and the innovative Axle Lubrication Management (ALM) system.

Available Transmissions

Detroit has taken the long-proven DT12 automated manual transmission and made it even better. Now you can spec your DT12 as direct-drive or overdrive, and even add a PTO for those highway applications that need one.

Learn More >

Detroit DT12-HE

Automated Manual Transmission

  • Torque Range up to 2,250 lb-ft.
  • GCW 160,000 lbs
  • Rear PTO Optional
  • Side PTO Optional

Detroit DT12-HL

Automated Manual Transmission

  • Torque Range up to 1,650 lb-ft.
  • GCW 80,000 lbs
  • Rear PTO Optional


Manual Transmission

  • Torque Range up to 2,250 lb-ft.
  • GCW Unlimited
  • Rear PTO Yes
  • Side PTO Yes


Western Star logo that features 'Serious Trucks' in white text and a red star against a gray background.