The tutorial describes the design and basis for the calculation of wheeled tractors used as base machines with various construction and road equipment. The design of wheel tractors of domestic and foreign production, the nature and features of the work of tractors with mounted, trailed and semi-trailer working equipment are considered; recommendations are given for the study of unified units and assemblies in the design and production of construction and road machines. The basis of traction calculations for the strength of the most important components and assemblies of these machines are given, reference data of a technical and economic nature are given.