Geometric Center Of Clubface:
First, the clubhead is measured to determine the Geometric Center of the face, where the face centerline is. Then, the Center of Gravity (C. of G.) is identified by measuring in two planes — up the clubhead in a vertical position, and across the horizontal plane of the clubface. Then the location of the C. of G. is compared to the Geometric Center of the face and other reference points, as follow:
Vertical Center of Gravity:
The distance from the C. of G. of the clubhead to the groundline.
Lower Vertical C. of G. = More Consistent Trajectory
Lower Vertical C. of G. = More Solid Hits
Lower Vertical C. of G. = HIGHER PLAYABILITY FACTOR
Horizontal Center of Gravity — “C” Dimension:
The distance from where a vertical line dropped from the C. of G. of the clubhead intersects the groundline from the point where the centerline of the hosel intersects the groundline. Greater Horizontal C. of G. = Larger Sweet spot
Greater Horizontal C. of G. = More Solid Hits
Greater Horizontal C. of G. = HIGHER PLAYABILITY FACTOR
Rearward Center of Gravity:
The distance from the C. of G. of the clubhead to the centerline of the hosel, measured front to back with the centerline of the hosel in a vertical position.
More Rearward C. of G. = Slightly Higher Trajectory With The Same Loft
More Forward C. of G. = Slightly Lower Trajectory With The Same Loft
Moment of Inertia (M.O.I.):
The tendency of the clubhead to resist twisting around its C. of G. in the heel-toe direction (a function of how much the total mass is distributed away from the center of gravity, towards the heel and toe).
Greater M.O.I. = More Distance On Off-Center Hits
Greater M.O.I. = More Solid Feel On Off-Center Hits
Greater M.O.I. = Better Directional Control On Off-Center Hits
Greater M.O.I. = HIGHER PLAYABILITY FACTOR