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