Smash Factor - Part I

If I had money for every time I’ve read about Smash Factor in the last few months then I’d have a fair bit of money yet, surprisingly, still be fairly in the dark about what it actually is. It’s definitely the kind of thing that you think you understand until you try to explain it…and then realise that you really don't have a clue.

It may have been around longer, but the term has definitely become more prominent in the past 10 or so years as a result of the growth of launch monitors and tracking systems.

But what is it???

Simply, smash factor is a measure of how effectively a player can transfer the speed of the club into the speed of the ball.

Okay, so it’s just how well you hit the ball?

Not quite. It’s not to be confused with launch angle, spin rate, shaft type, etc all of which can also affect the length and accuracy of a drive. (I will discuss these in later blogs so watch out for them!)

So how do you effectively transfer the speed of the club into the speed of the ball?

Are you ready? Here comes the science bit!

Smash factor is based on collision theory and the important factors for golfers are:

• The mass of the golf ball (fixed by regulation) 
• The mass of a “normal” driver (around 200g) 
• The face angle of the club (assume a 10º face) 
• The coefficient of restitution (COR) (maximum 0.83 set by R&A and USGA)
• The miss - the distance that the miss the sweet spot by (in inches) 

[Just to keep things straight - one thing at a time - COR is a number between 0.1 and 1 that shows how much things bounce when they hit each other. If 2 objects just stop on impact the COR would be 0. The COR relates to the collision and is the relative speed after collision divided by the relative speed before collision.]

I feel like I should suggest taking a breather here - I really want this to be as simple as possible but with all the calculations and fancy words it’s not easy!

So, what I’ll do is break this into a number of posts and then do a nice summing up at the end of it all.

The only thing you need to remember from this post is:

Smash factor is a measure of how effectively a player can transfer the speed of the club into the speed of the ball.