Moment of Inertia (MOI): How Does it Affect Your Golf?

The latest buzz word in golf equipment manufacturing is "Moment of Inertia" or MOI for short. But what exactly is it and how does it affect your golf?

Very simply, MOI can be described as a measure the resistance an object has to turning about its axis.

There are several factors relating to golf clubs and MOI.

1) MOI of the whole club

Each club will have an overall MOI i.e. a measurement of the effort required to swing the club. This is akin to the Swing Weight scale which was developed as an easy way to get all clubs in a set to feel the same when you swing them. A club with a high Swing Weight feels heavier to swing. Similarly, a club with a high MOI takes more effort to swing.

2) MOI of the club head

The club head itself has a MOI related to the effort required to twist it about its centre of gravity at impact with the ball. The higher the MOI the less the club head will twist. The less it twists, the higher the chances of a straight shot.

In marketing terms you will only really ever hear about the MOI of a club head, and even then it is mostly referring to drivers. However all clubs have a MOI. For instance perimeter weighting in a putter increases its MOI, allowing it to resist twisting when you strike the ball, leading to more consistent putts.

A higher MOI will not give you more distance with your driver, but will reduce the chance of the club head twisting, and therefore increase the probability of straight hits. The more you can hit straight shots, the better scores you will produce.