The measurements of the disks and hoop in the Centripetal Force Apparatus Moment of Inertia Accessory Kit (CFA-MIK) are as follows:

Disk: 
Mass 0.462 kg
Radius 0.089 m (outer edge)

Disk w/groove: 
Mass 0.444 kg
Radius 0.089 m (outer edge)

Hoop: 
Mass 0.428 kg
Radius 0.076 m (~middle of hoop material)

There is some variability unit to unit. We strongly recommend that you measure these parameters, if that is critical to your activity.