Despite the disadvantages in aspects of ride comfort due to the thick sidewall, sidewall reinforced run-flat tires, compared to other types of run-flat tires, have more advantages in use of commercially available rim, easy assembly of tire and rim and manufacturing processibility. In this paper, the design concepts and problems encountered in the development of sidewall reinforced run-flat tires are studied. The condition of no internal air pressure under the vertical load induces the severe bending force on the sidewalls of the tire. To develop the sidewall reinforcing rubber compound and the sidewall construction to support this bending force efficiently are the core concerns for designing the sidewall reinforced run-flat tire. The bending force also causes a problem of bead unseating from the rim. In addition to that, another problem is how to solve the manufacturing process problems which come from thicker sidewall compared to the standard tires. Finite element method was widely used to understand the basic mechanism and to design the construction of the run-flat tire.