Specimens cut from a 40 × 14 nylon cord aircraft tire were subjected to cyclic strain tests to measure the viscoelastic behavior. Spectral analysis was used to quantify nonlinearity in the stress response. Preliminary studies were made to ascertain the effects of specimen length and width on the test results. A bolted end constraint was developed to uniformly distribute the imposed strain through the thickness of the multiply carcass specimens. Test results show the effects of temperature, frequency, and strain level on the viscoelastic properties. Results are generally in agreement with earlier findings made using tubular test specimens.