A method and apparatus for collecting ultrasonic test data from a railway wheel with an ultrasonic testing apparatus is described. The railway wheel is supported by two drive rollers, each having an indentation which engages with and rotates the wheel. An indexing transducer moves across the rotating wheel, collecting ultrasonic test data while a fixed transducer correlates a reference position on the wheel to the collected test data. To maintain the accuracy of the reference position to the collected test data, it is desirable to maintain the rotational stability of the wheel, minimizing any dynamic instability caused by dimensional tolerances in the wheel. To mitigate instabilities resulting from dimensional tolerances, the indentation of the drive rollers, which engage and drive the flange of the wheel, are variably spaced using a resilient member to maintain frictional contact between the wheel and the drive roller. This allows the indentation to accommodate the varying dimensional tolerances of the wheel flange, mitigating the possibility of dynamic instability resulting from departure of the wheel flange from the indentation.