Description of Pololu Wheel 42×19mm Pair Product package contains two (2) wheels. This custom-designed white plastic wheel has a rubber tire measuring 1.65" (42 mm) in diameter and is designed to fit the output shafts on our micro metal gearmotors. These gearmotors should be mounted onto the side of the hub with the protruding teeth. The output shaft will slide into the socket easily at first but will achieve a snug fit when pressed through to the other edge of the hub. Teeth on the hub optionally allow a reflectance sensor to be used for encoder feedback. These wheels are sold in pairs. Encoder Feedback The hub has twelve teeth, each 3 mm wide and separated from its neighbors by 3 mm gaps. We offer a quadrature encoder that uses these teeth to provide up to 48 counts per revolution (a linear resolution of just under 3 mm or 1/8"). The encoder can be purchased as an individual unit.
