Executive Summary

The purpose of a chassis fairing, sometimes called a chassis or fuel tank skirt, is to provide a clean aerodynamic surface and eliminate the steps, air, fuel and diesel fluid tanks, battery boxes, etc. that increase the drag of an exposed chassis. They also are designed to kick air slightly outboard of the tractor drive wheels, preventing the air from directly impacting the face of the tire tread. 

Chassis fairings run from the cab steps to the end of the sleeper or with extensions to the first drive wheel.

Sleeper chassis fairings generally are required for SmartWay designated tractors.

Tractor Aerodynamics
What Fleets Are Saying

“We continue to update our fleet with more fuel efficient post-2014 U.S. Environmental Protection Agency emission compliant engines, install aerodynamic devices on our tractors, and equip our trailers with trailer blades, which all lead to meaningful improvement in fuel efficiency.” — Knight Transportation

“Appearance and detail of our equipment means a lot to our drivers. Drive wheel fairings don’t just save us money, but our drivers like them too.” — Brad Pinchuk, Hirschbach

“Sleeper tractor aerodynamics have been finely tuned by all OEMs. Eliminating various features can add 10% to a fleet’s fuel expense,” — Chief engineer at a major truck builder.

 

Decision Making Tools

The Confidence Matrix has been issued to help fleets make decisions about tractor aerodynamic devices.

Decision-Making Tools

Conclusions
  • Fleets should use the standard, optimized aerodynamic packages developed by tractor manufacturers. 
  • Fuel efficiency can be lowered by about 10% by moving to partial or no aerodynamics.
  • Tractor and trailer ride heights should be matched for as many miles driven as possible.
  • Fleets operating day-cab tractors should pursue greater adoption of tractor aerodynamics.
  • Tractor manufacturers should design and make available aerodynamic features for day-cab tractors including those powered by natural gas.
  • Future EPA and NHTSA Greenhouse Gas Regulations will continue to challenge tractor builders to improve the aerodynamic drag of these vehicles.
Manufacturers
  • Daimler Trucks North America
  • International
  • Kenworth Truck Co.
  • Mack Trucks
  • Peterbilt Motors
  • Volvo Trucks North America