Audi Glossary

Audi Glossary
AA6_D_10773Phantom drawing of the Audi A4 (B7) Saloon showing drivetrain and suspension

Cd value

The cd value is the aerodynamic drag coefficient. It is used as a comparative value to assess the aerodynamic efficiency of the shape of a body. Since this value is a coefficient, it is dimensionless. It is calculated from the force measured as a constant speed and the projected surface (frontal area) of the object being measured. The lower the cd value, the more smoothly the vehicle passes through the surrounding air. (See also: aerodynamic drag.)