Wheel covers are inserted into the wheel of all tires to streamline the airflow around the tires and can be used on all six wheel ends of a tandem axle tractor.

A variety of manufacturers produce aerodynamic wheel covers, and small benefits can be achieved by using them as part of an overall fuel efficiency strategy. Wheel covers are made of a variety of materials including aluminum, polycarbonate, and even cloth.

The primary design challenge has been making it possible to easily remove the wheel covers so that the wheels are accessible, while maintaining strong attachment to the vehicle over the road.

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.


  • 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.


  • Flow Below
  • Deflecktor
  • Aerotech Caps
  • Real Wheel Covers