Freewheel mechanisms are used in kinematic chains of technical systems of a various functionality. When such mechanisms freewheeling, it is necessary to ensure that there is no contact of their working elements to reduce friction losses and wear. At the same time, it is necessary to ensure the minimum value of the idling angle affecting the accuracy and response time of the kinematic chain in which the mechanism is installed. The task of analyzing and determining the geometric conditions allowing ensuring a radial gap between the working elements of the eccentric freewheel mechanisms with free-running engagement has been set. To solve this problem, a design scheme is proposed and a mathematical model describing the relationship between the geometrical parameters of the mechanism is obtained. The nature of the influence of the basic geometric parameters (eccentricity, radial clearance, modulus, etc.) on the value of the idling angle is established. It is shown that when designing, the values of the module and the gap should be chosen as the minimum permissible, taking into account the load capacity and the assembly conditions. The eccentricity can be assigned based on the requirements of the manufacturing technology.