The paper deals with the experimental measurement of the tyre casing defects for the freight vehicles at the dynamic loading. The given investigation was mainly focused on cracks and defects in tyre casing, which is commonly used for freight vehicles.  The mentioned measurement or investigation was performed under the strictly specified conditions. The given measurement of crack propagation in car tyre casing was based on changes of speed, changes of loading as well as changes of service time interval. It is important to point out that the pressure in the tyre was predetermined to be the constant value. The experimental procedures were carried out by help of special drum testing machine with designation: IGTT 25kN – C and with the 1707mm drum diameter. The mentioned measurement was performed for the area of tyre casing shoulder and it was in the site between the first and the second buffer lining. Using the ITT- 1 program relating to non-destructive testing analyser, the CCD camera for testing procedure of tyre casing was used for the camera images which were taken from the internal side of the tyre casing. The inspection of the tyre casing was performed for the specified points or segments around the periphery of he tyre casing. The measurement was based on simple cycle. The analyser testing led to creation of the resulting protocol based on ITTView program and on the basis of this program, it was possible to display or print this protocol in the form of the phase image mode or video mode.  The crack propagation was evaluated on the basis of tyre casing loading as well as kilometres which were overrun during the car service. Shearograpy is a method which can be used for specification of tyre casing cracks under the laboratory conditions and it can be also useful during the quality inspection of the new made products. The obtained knowledge relating to crack initiation and propagation in tyres can be used for easier solutions referring to different areas and sites of the tyre casing and by this way, it is possible to determine which one of variants is the most suitable for utilisation in the production.

This work was supported by the Slovak Grant Agency VEGA 1/0649/17, VEGA 1/0589/17, KEGA 007TnUAD-4/2017, and resulted from the project “Center for quality testing and diagnostics of materials”, ITMS code 26210120046.