It is an acronym common in the world of golf, but what exactly does it mean? We take a look

What Does MOI Mean In Golf?

We have all heard golf adverts, equipment gurus and coaches use this acronym all the time to the point where they assume everyone knows what MOI means and what it actually signifies.

But that simply isn’t the case so let us explain.

The acronym MOI means ‘Moment of Inertia’ and in a golfing context this is a measurement of a club’s resistance to twisting.

When you strike the ball towards the toe of the club, the impact pushes against the toe of the face and that pushes it slightly open. The result is probably a block out of bounds to the right. Likewise in terms of the heel, the impact causes the face to close slightly.

Why is that important?

Well golf clubs with a high MOI mean the club twists less on off-centre strikes that allows the golfer to lose less distance and theoretically it shouldn’t go as far offline. The higher the MOI the more forgiving the club head is in terms of its sweet spot and strikes away from it.

If the moment of inertia can be increased, the club becomes more resistant to twisting. Therefore, a higher-MOI club-head will twist less on off-centre strikes than a lower-MOI one.

There is also a club-fitting aspect here because if the MOI is different in all of your clubs then this will hamper your consistency. It is said that if it is the same, then your consistency improves because each club requires the same effort to swing.

How do club manufacturers boost MOI?

The main way equipment manufacturers do this is by moving weight towards the edges and the perimeter of the head. This inevitably boosts the MOI up and has lead to the creation of super-game improvement irons, and explains why manufacturers put moveable weights on the perimeters of their woods. The TaylorMade M5 and Callaway Epic Flash drivers are a clear example of this as you can see below.

All of this explains why manufacturers, when they are talking about MOI, use the word in relation to forgiveness in the clubhead. But it should be acknowledged that there are several MOI’s in golf clubs, for example there is the MOI of the club-head around the shaft and the entire club in relation to the golfer.

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