The main contributor to elastomer friction on rough surfaces is hysteresis friction, which is caused by the dissipation of energy induced by sliding on a rough surface and the viscoelastic material properties of elastomers. For this presentation, a multi-scale hysteresis friction simulation using a set of sine waves as surface approximation is adapted to incorporate asymmetric surfaces. Since the surface approximation algorithm used for this analysis does not account for possible direction dependence of the original surface, an additional parameter is introduced to create slanted sine surfaces. Simulation results on symmetric sine surfaces are compared to results on slanted sine surfaces to show the significant influence of the sliding direction on the coefficient of friction for pure hysteresis friction.