Detectable indicia are provided on the interior circumferential rim of the brake hub-drum adjacent to, and spaced apart from, the backing plate of the brake. A sensor is mounted on the backing plate to detect wheel speed and/or other operating conditions detectable from the motion and/or relative location or condition of those indicia. The number of indicia used and the indicia spacing along the interior circumferential rim is selected as needed for a given type of sensor and/or a given application. In the case of a speed sensor, the indicia can be a series of notches in the rim along the entire interior circumferential rim, resembling a series of “teeth” into that rim. The width of those teeth can be formed wide enough to accommodate movement of the hub-drum relative to the backing plate and/or the sensor, without loss of system functionality, according to the sensing tolerances of a given sensor being used in a given application.