What is the power transfer ratio (PTR) formula?

What is the power transfer ratio (PTR) formula?

• A. Ball Speed ÷ Ball Spin = PTR
• B. Ball Speed ÷ Clubhead Speed = PTR
• C. PTR = Ball Speed × Clubhead Speed
• D. Clubhead Speed ÷ Ball Speed = PTR

Answer: (B)

The idea here is to describe how efficiently energy is transferred from the club to the ball. PTR is defined as ball speed divided by clubhead speed at impact. This ratio shows how fast the ball leaves the club relative to how fast the clubhead was moving, giving a sense of transfer efficiency (often expressed as a number or a percentage). A higher PTR means more of the club’s speed is converted into ball speed. The other formulations don’t measure this efficiency: dividing ball speed by spin mixes different quantities and isn’t about transfer efficiency; multiplying the two speeds isn’t a meaningful measure of energy transfer; and dividing clubhead speed by ball speed is the inverse of PTR, not the ratio used to gauge how effectively speed is transferred to the ball.

The idea here is to describe how efficiently energy is transferred from the club to the ball. PTR is defined as ball speed divided by clubhead speed at impact. This ratio shows how fast the ball leaves the club relative to how fast the clubhead was moving, giving a sense of transfer efficiency (often expressed as a number or a percentage). A higher PTR means more of the club’s speed is converted into ball speed.

The other formulations don’t measure this efficiency: dividing ball speed by spin mixes different quantities and isn’t about transfer efficiency; multiplying the two speeds isn’t a meaningful measure of energy transfer; and dividing clubhead speed by ball speed is the inverse of PTR, not the ratio used to gauge how effectively speed is transferred to the ball.