The source provides an extensive explanation of the gear effect in golf, a physical phenomenon crucial to understanding how the ball spins and curves following off-center contact with a clubface. Rooted in the physics of angular momentum and torque, the gear effect occurs primarily in woods and hybrids, where striking the ball on the toe or heel causes the clubface to twist, imparting corrective sidespin on the ball, such as a draw from a toe hit or a fade from a heel hit. The episode details how club design, particularly the bulge and roll of the clubface and a high moment of inertia (MOI), is engineered to leverage this effect, improving shot forgiveness and allowing advanced players to intentionally shape their shots. Ultimately, the source emphasizes that understanding the gear effect is essential for golfers when making equipment choices, adjusting for mishits, and improving overall shot consistency.