An air duct for cooling rotating tires that broadly funnels or directs air up and into the face of an air fender or rotating tire. The air duct comprises a depending wall having an upper and a bottom edge. Formed within the wall is a leading tunnel section in communication with a baffle section, the tunnel section having a discharge end. The tunnel section defines at least one flow path which channel ambient air through the discharge end and into the baffle section where the air is subsequently directed into the face of air fender or rotating tire. The baffle section is defined as being between the discharge end of the tunnel section and the either the leading surfaces of an air fender or where there is no fender, the leading surfaces of the associated tire.