The article considers the issue of calculating the gear teeth number and selecting the center distances values for the kinematic diagram of a fixed-ratio hub-reduction gear with single-row shaft drive, in which power is transmitted from the driving to the driven gear through two idler (intermediate) gears. The advantage of this design is the loads reduction in gear engagements and symmetrical distribution of reactions. The need to perform evaluation calculations was caused by the difficulty of using traditional packages “KISSoft” and “KOMPAS” in design. The Kirovets tractor lineup was chosen because the possibility of replacing the drive wheels with triangle crawler tracks is being considered, which leads to an increase in the height of the chassis’ center of gravity and there is a need to design a portal drive axle.