The reliability of the cereal combines depends mostly on the reliability of the propulsion belt variators which they are equipped of, because the out of working of the propulsion belt variators immobilises the combines and their restore is difficult and with important period of immobility.The reliability study of the propulsion belt variations consists in the determination of the belt life period, the belts being the variation most sensible elements. In order to determine the life periods of the variators belt, a computer programme was realized based on the variator belt working. The programme results aloud to identifier the most unfavourable regimes and the ways to avoid them.
