The structure of the inner belt weatherstrip can be divided into a carrier, upper and lower lip, and flocking for the upper and lower lips as shown in Figure 1(a). The carrier is fixed to the door body in white (BIW), and it is composed of polypropylene (PP) material. The lip contacts to the glass sealing the gap between the carrier and glass. The material candidates for the lip are TPV or ethylene propylene diene monomer (EPDM). Flocking, made of PE or PA, is attached to the lip to reduce friction with the glass surface. The overlap distance between the glass and the lip corresponds to dimension ⓐ in Figure 1(a). The contact load (L) is the reaction force generated when the inner belt lip contacts the glass, as shown in Figure 1(b).