gravity tends to be slightly toward the topline in relationship to the center scoreline or mid point of the face.

Vertical gear effect occurs when the ball makes contact higher or lower than the actual center of gravity. If the impact is made above the CoG, the face will rotate and increases the loft. Impact made below the CoG will de-loft the clubface. As the head rotates, the vertical roll will impart the opposite spin to the ball.

An impact made high on the face above the CoG will create a higher launch angle, and the vertical gear effect will actually cause the ball to spin less. This can produce greater distance as the ball is subject to less lift or drag that a higher spin creates. An impact made below the CoG will cause the ball to fly at a lower launch angle. However, the positive effect of the vertical gear effect will increase the spin rate of the ball to help maximize trajectory and distance.