There is considered the plane motion of rolling wheel in conjunction with geometric and power relations of forming of contact area. There is established that the transformation of the connection is accompanied by mutual deformation of contacting surfaces with arising of friction forces, caused by the repacking of soil particles and other factors. There is defined the energy state of the “wheel-contact patch” system and its general characteristics of movement.

There is considered the process of forming of contact area by 4x2 wheel chassis with elastic circuit of power flow input. There was developed the method of calculating of tractive characteristics, amplitude-frequency and phase-frequency characteristics of motion of the “wheel-contact area” system. There was got the transfer function establishing a connection between input and output parameters, allowing to design measuring and information vehicle onboard system with determination of its parameters (motion parameter dead-band of measurement system, ranges of measurements and characteristics of sensors, devices, etc.).

Possibility of self-excitation of wheeled tractor frame oscillations in longitudinal plane during the operation in tractive mode is theoretically substantiated. Dependence of rolling radius of a pneumatic wheel on vertical load and on driving moment level, mathematical model describing pneumatic wheel rolling under variable vertical load and two-mass lineal model describing tractor frame oscillations in longitudinal plane are used.