For a reasonable and reliable assessment of durability at the design or operation stage of the tracked vehicles, it is required information about the loading process, which is usually obtained by registering the load by various methods, such as strain measurement. For a reliable assessment of loading and, consequently, durability, the question arises about the representative length of the loading process recording. The paper proposes a method for determining the necessary and sufficient realization length using various methods of processing of the recorded random loading realization. The efficiency of the proposed method is demonstrated by the example of the evaluation of the random loading processes in torsion shafts of the suspension systems of a high-speed tracked vehicle. The justification of the necessary and sufficient length of the record of the random loading process is given.