The wheel inspection systems using ultrasonic technology seeks out flaws and cracks by means of the propagation of Rayleigh ultrasonic waves produced electromagnetically on the rolling surface. The Rayleigh waves propagation through the surface defects determines the development of reflected waves that are automatically identified by the signal acquisition and processing software. The inspection system needs no coupling medium and its performance is independent of the surface conditions of the wheel, allowing proper operation even with rough or dirty surfaces.