A high speed, natural frequency type, fatigue testing machine has been evaluated for testing automotive wheels. Rim stress correlation between service loading and machine loading is good and fatigue failures are produced in the predicted areas of the rim. Although fixtures were modified to test other parts of the wheel, no consistent patterns of failure were apparent. The value of this type of testing is that a large number of load cycles are applied in a short time. Its first use will be as a quality control check in manufacturing rims.