Hybrid/merged cords made by blending dissimilar yarns into a single cord are commonly used in tire applications. This method is used to capture the desirable properties of each component. In nylon (PA66)/aramid (A19) cord constructions, the aramid is used for its superior strength and thermal stability. The nylon is used for its high elongation. In tire numerical modeling, the composite components require two types of input data, one related to the initial thermal strain, coefficient of thermal expansion (CTE), and one related to the growth/creep viscoelastic response, creep factor (cr_fr). The following article provides a summary of the laboratory measurements of these material properties for the commonly used hybrid/merged cords. A consumer tire with reinforcing layers was analyzed under normal inflation and loading conditions. The impact on the tire's outer contour and footprint characteristic was shown to be dependent on the type of cord materials used, its initial thermal strain, and its viscoelastic behavior.