Trackman Essentials Pt.3: Smash Factor (Pt.1)

Now, if you remember, smash factor describes the ‘efficiency’ of the strike. If you ever forget the formula for smash factor, you can easily derive it from the formula for efficiency.

Efficiency = Useful energy output / input energy

The formula for smash factor is very similar, with useful energy output being ball speed, and input energy being club head speed.

Smash factor = Ball speed / Club head speed

However this is a very simple formula, which should (more or less) give you the correct answer.

The full formula is this:

This is essentially the same formula, as it can be more or less simplified into Efficiency = Useful output energy / Useful input energy. COR means coefficient of restitution, which is how much energy is transferred back into an object when it strikes another. COR depends on the material of the club face (usually titanium). Spin loft can directly influence smash factor, as the higher the spin loft is, the more of a ‘glancing blow’ is delivered. Now, if you cast your mind back to Year 4, you’ll remember that if the numerator of a fraction increases, the number becomes bigger. However, looking at this formula, you may think that a higher spin loft would increase smash factor. That’s where the cosine comes is.

A high spin loft for a driver is about 16 degrees. Cos 16 = 0.9612617

A low spin loft is near 9 degrees. Cos 9 = 0.98768835

As you can see, a lower spin loft does produce a higher result when ‘cosined’. Although it’s not a big change, it does effect the overall smash factor.

The other two other components of the full equation are ball mass and club head mass. The higher the club head mass is and the lower the ball bass is, smaller the denominator of the full equation becomes. This results in the overall smash factor increasing.

This video should demonstrate the basics of smash factor: https://youtu.be/OFvqOXA1YY8

Hopefully this entry has been engaging & informative, and I’ll see you next Sunday, with another post. Bye!