The structural characteristics of orthotropic and anistropic composites made of several tire belt reinforcements and rubber are measured and reported. Characteristics are obtained as a function of strain level and ply angle for one- and two-ply composites. Hysteretic loss data under sinusoidal cycling at various initial strain levels are reported. Photoelastic experimental analysis techniques for measuring strains are discussed. An electrohydraulic tester with strain gage extensometers and a reflection polariscope were utilized in the studies. Composite structural characteristics affect tire deformations and, consequently, the stresses that are developed in tire components as well as heat build-up and rolling resistance.