The pneumatic tire has a very complicated geometrical shape and is subjected to large deformations. Measurement of the stress and strain distributions in the tire is difficult. In this study, the reflective photoelastic method was used to measure the distributions of stress and strain on the surface of the tire sidewall. It was assumed that the pneumatic tire takes the shape of a toroidal shell of revolution and that the strain of the photoelastic coating is the same as that of the tire surface. The force equilibrium equations for shell elements were derived and the principal stresses were extracted by the shear difference method. The normal stresses and the shear stresses were obtained by numerically integrating the equilibrium equations. The initial values for the integration were determined using the oblique incidence method.