About this 3D model

More durable shell. The wheel has diameter ~5 cm/~2 inches. Motor has a gearbox. Bearing is from roller skates (D=22mm). Motor shell can be fixed on the bearing by 3mm bolt. Mounting holes have D=3mm. Two versions of wheels - with teeth on hub and on opposite side. This is used in the robot vacuum cleaner: http://www.instructables.com/id/Floor-vacuum-cleaner-robot-controlled-by-Arduino-w-1/