A wheel service machine comprising: - a frame; - a wheel-holder unit rotating about a first axis; - a roller rotating about an axis parallel to the first axis; - a connecting structure to movably connect the roller to the frame, wherein the roller is movable towards and away from the wheel-holder unit along an operating trajectory such that the axis of the roller remains parallel to the first axis, between a position of non-interference with the tyre of a wheel mounted on the wheel-holder unit and an active position where it applies a predetermined force to the tyre tread, wherein the connecting structure comprises an articulated arm having a first end and a second end, wherein the first end of the articulated arm is coupled to the column to rotate about a fifth axis and the second end of the articulated arm is coupled to the roller; - at least one force sensor connected to the roller for measuring values of a force parameter representing a radial force transmitted to the roller by the tyre; - at least one position sensor configured to measure values of a position parameter representing a position of the roller relative to the frame; - a processing unit connected to the at least one force sensor and to the at least one position sensor, characterized in that the processing unit is configured to calculate, as a function of the position parameter, a geometrical parameter representing a distance between the first axis and a surface of the roller in contact with the tyre tread when the roller is in the active position, and is configured to derive a pair of values, the pair of values comprising a value of the radial force, measured by the force sensor when the roller is in the active position, and a corresponding value of the geometrical parameter calculated, wherein the processing unit further contains data relating to geometrical dimensions of the machine, including a length of the articulated arm and a radius of the roller, to calculate a position of the axis of the roller based on trigonometric relations. - a frame; - a wheel-holder unit rotating about a first axis; - a roller rotating about an axis parallel to the first axis; - a connecting structure to movably connect the roller to the frame, wherein the roller is movable towards and away from the wheel-holder unit along an operating trajectory such that the axis of the roller remains parallel to the first axis, between a position of non-interference with the tyre of a wheel mounted on the wheel-holder unit and an active position where it applies a predetermined force to the tyre tread, wherein the connecting structure comprises an articulated arm having a first end and a second end, wherein the first end of the articulated arm is coupled to the column to rotate about a fifth axis and the second end of the articulated arm is coupled to the roller; - at least one force sensor connected to the roller for measuring values of a force parameter representing a radial force transmitted to the roller by the tyre; - at least one position sensor configured to measure values of a position parameter representing a position of the roller relative to the frame; - a processing unit connected to the at least one force sensor and to the at least one position sensor, characterized in that the processing unit is configured to calculate, as a function of the position parameter, a geometrical parameter representing a distance between the first axis and a surface of the roller in contact with the tyre tread when the roller is in the active position, and is configured to derive a pair of values, the pair of values comprising a value of the radial force, measured by the force sensor when the roller is in the active position, and a corresponding value of the geometrical parameter calculated, wherein the processing unit further contains data relating to geometrical dimensions of the machine, including a length of the articulated arm and a radius of the roller, to calculate a position of the axis of the roller based on trigonometric relations.