What does MOI (Moment of Inertia) mean and is it important?

What does MOI (Moment of Inertia) mean and is it important?

Why is MOI so important to golfers ? if you want the ball to go straighter, here's why you should be looking out for it.

What does Moment of Inertia (MOI) mean and is it important?

MOI is defined as
A measure of a body’s resistance to angular acceleration (twisting). In golf, MOI comes most into play on imperfect contact, when the ball and the clubface meet someplace other than the middle of the face/sweet spot.

Another way to look at MOI is in figure skating.

If the skater starts to spin on the ice with their arms out wide from their body. This would replicate a HIGH MOI.  Then, when they pull in their arms tight and closer to the body. There is a LOW MOI and the spin/rotation is much faster.

So to break it down,
Wide area = High MOI = Slower spin / rotation
Smaller area = Low MOI = Faster spin / rotation


So WHY is MOI so important to golf and golfers?

MOI in golf is effectively what makes a golf club “Forgiving
If you want the ball to go straighter, you should be looking out for it.


Having a club that has a high MOI is VERY important.
Let me explain:

  • The main reason that the Drivers of today are the size they are and the reason why they are limited to a maximum of 460 cc’s is largely down to restricting the measure of MOI.
  • The larger you make the head, the more the weight moves to the outside of the head and away from the centre of the clubhead ( skaters arms out wide) which makes the clubs MOI high and so it twists less or is more forgiving when hit off centre in the face.
  • So, having a big headed Driver, Fairway Wood and even Hybrid that has a lot of peripheral or outer weighting is a good thing. A club that has adjustable weights at the outer edges of the head is an even better way to make the club create a higher MOI and therefore more forgiving than a club without it.

So now that you understand MOI better and HIGH MOI
Would anyone actually need a LOWER MOI club ?
Yes, sometimes:

  • Usually we see a golfer who is a good solid ball striker and is fairly consistent with their misses on the face prefers a MOI club setup.
  • They will want to shape the ball more and create different shaped shots.
  • They will usually prefer a smaller looking head (perhaps a 430cc size) and won’t need as stable a head so that they can actually make the club twist easier and thus move the ball in the air easier.
  • The HIGHER the MOI the harder it is for these kinds of golfers to work the ball.
  • It’s occasionally why you might see a Tour player using the larger 460cc head as he or she wants to hit the ball straighter with less movement from the head and then other players will have a smaller 400-430cc head.
  • With today’s range of different drivers that have numerous weights that slide around and throughout the head the MOI gets affected, sometimes very negatively.

Make sure you keep this in mind

If you’re struggling to hit your current driver and you switch to a different one to gain a few more yards – be careful, you don’t misunderstand what your new “lower spinning higher launching driver” can do to your game.
You could end up with a driver that drops in MOI and is actually less forgiving than your old one.

MOI is something that we take very seriously at ForeGolf because it’s the only thing that affects the “Forgiveness Factor” of your Driver.

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