What are the dimensions of the wheel on the Rotary Motion Sensor?

The measurements are as follows:

Diameter of small groove: 10 mm
Diameter of medium groove: 29 mm
Diameter of large groove: 48 mm
Diameter of outer: 52 mm
Diameter of outer with rubber O-ring installed: 55 mm

Moment of Inertia for 3-step pulley: approx. 2.7 X 10^-6
Moment of Inertia for shaft and encoder: approx. 1.1 X 10^-6