This study investigates the high shear rheology of grease and determines whether the "normal stress effect" can significantly contribute to film formation in radial lip seal applications. Rheology measurements and a rheology model for the grease have been developed to model the normal stress at high shear rates. Subsequently, a seal lip model is developed to predict lift forces, generated by the normal stress effect. The model predicts lift forces over 50% of the seals specific lip force for low contact pressure bearing seals.