This paper outlines the technical challenges experienced and engineering methods used to overcome them during the endeavor to reduce wheel hub units mass and friction. Results achieved by the project team are significant and have meaningful contributions both to the unsprung mass, inertia and rolling resistance reduction. These features directly enable fuel consumption reduction and related CO2 emissions as well as positively influencing vehicle dynamics.The two part paper handles the subjects of weight reduction and drag related power loss improvement and their combined effect at vehicle level. It provides both simulated and test measured data as well as the validation of various features. This first part will focus on the friction reduction with only an introductory mention on the weight reduction effort.In the very near future every milligram of CO2 reduction will count. To achieve significant improvements engineers have to think out of the box, develop break through technologies and sometimes totally rewrite the rule book. This paper outlines how the project engineers have approached the problem, used modeling techniques to simulate various solutions, conducted technology scouting, selected new technologies, prototyped and fully validated robust products.