Abstract: An undercarriage tyre burst during the process of routine gas charging. In order to find out the failure cause, macro and micro observation, wall thickness and groove depth measurement, and material performance analysis were carried out. The results show that the cracking of the tyre initiated from the X-type crossover point of the thread, presenting linear source feature. Stress aging of the rubber is the main cause for the burst of the tyre under the effect of external force.