While brass coated steel cords are extensively used as reinforcement material in radial tires, bronze coated wires are the foundation reinforcement of tire beads. It is crucial for the performance and life-span of passenger and truck tires to achieve optimal adhesion between rubber and steel. This presentation will review the adhesion build-up and degradation mechanisms of the adhesion interphase layer, that bonds brass coated steel cords and bronze coated steel wires with rubber. Other topics include standard adhesion tests, advanced interphase studies, current state of the art technology and what the future holds for improving rubber adhesion.