MOI and Game-Improvement Golf Clubs (Video) - by Pete Styles
MOI and Game-Improvement Golf Clubs (Video) - by Pete Styles

Another abbreviation you might come across when you’re looking at buying some new golf clubs is MOI, something a lot of manufacturers talk about that their driver has more of this or less of that and all that sort of thing. MOI stands for Moment of Inertia and it describes how the golf club would twist when it’s hit.

There's a huge twisting force that goes through any golf club because the shaft comes down here and you’re hitting that bit, so there’s a huge twisting force going through here particularly if you then factor in the issue that a lot of golfers won’t hit the center of the golf club every time. And that often, golf club performance is actually graded on how well it performs when you don’t hit the middle. It would be lovely if we just struck the dead center every single time, but we don’t do that, we’re not robots, we’re always going to be off-center on occasions, and the golf club’s performance is often graded on how did it perform on the toe, how did it perform on the heel or the top, or the bottom.

And a golf club that can perform better in those areas would be considered a golf club that’s more suitable for a wider handicap range. So a golfer who’s playing over 28 handicap aren’t going to play with a driver that only works when you hit the dead center. They need a driver that works when you hit all over the club face. So moment a high moment of inertia is good when you’ve got a nice, wide club head, with a lot of weight on both sides that would therefore twist a lot less.

You’ll actually see the Moment Of Inertia argument carried on right away through irons and even into putters, a lot of putters now have a heel and a toe weight, or even balls that come after the back of the heel and the toe of the putter. And again, that’s to stop the club face twisting as you hit through the impact area. When you’re striking dead center on the putter that’s fine, but if you hit the toe or the heel, you don’t want the club head to twist too much.

Another analogy you might be able to follow, is that idea of an ice skater who spins around. When an ice skater spins around, if they stretch out a leg and an arm to one side, that’ll actually slow down their rotation even though the mass doesn’t change, their weight doesn’t change, they’ll slowdown the rotation. If they then took their arms into the central part of their body, the rotation speeds up, something wants to rotate quicker if its center of gravity is nearer the middle.

So, if you made a golf club where all of the weight was in the center, it would be quite happy to turn one way or another way which is not a good thing for a golfer. So a good high moment of inertia is the weight of the golf club moves to outsides, the heel and toes as we were describing, and that would actually perform better on the off-center hits.

 2012-06-11

Another abbreviation you might come across when you’re looking at buying some new golf clubs is MOI, something a lot of manufacturers talk about that their driver has more of this or less of that and all that sort of thing. MOI stands for Moment of Inertia and it describes how the golf club would twist when it’s hit.

There's a huge twisting force that goes through any golf club because the shaft comes down here and you’re hitting that bit, so there’s a huge twisting force going through here particularly if you then factor in the issue that a lot of golfers won’t hit the center of the golf club every time. And that often, golf club performance is actually graded on how well it performs when you don’t hit the middle. It would be lovely if we just struck the dead center every single time, but we don’t do that, we’re not robots, we’re always going to be off-center on occasions, and the golf club’s performance is often graded on how did it perform on the toe, how did it perform on the heel or the top, or the bottom.

And a golf club that can perform better in those areas would be considered a golf club that’s more suitable for a wider handicap range. So a golfer who’s playing over 28 handicap aren’t going to play with a driver that only works when you hit the dead center. They need a driver that works when you hit all over the club face. So moment a high moment of inertia is good when you’ve got a nice, wide club head, with a lot of weight on both sides that would therefore twist a lot less.

You’ll actually see the Moment Of Inertia argument carried on right away through irons and even into putters, a lot of putters now have a heel and a toe weight, or even balls that come after the back of the heel and the toe of the putter. And again, that’s to stop the club face twisting as you hit through the impact area. When you’re striking dead center on the putter that’s fine, but if you hit the toe or the heel, you don’t want the club head to twist too much.

Another analogy you might be able to follow, is that idea of an ice skater who spins around. When an ice skater spins around, if they stretch out a leg and an arm to one side, that’ll actually slow down their rotation even though the mass doesn’t change, their weight doesn’t change, they’ll slowdown the rotation. If they then took their arms into the central part of their body, the rotation speeds up, something wants to rotate quicker if its center of gravity is nearer the middle.

So, if you made a golf club where all of the weight was in the center, it would be quite happy to turn one way or another way which is not a good thing for a golfer. So a good high moment of inertia is the weight of the golf club moves to outsides, the heel and toes as we were describing, and that would actually perform better on the off-center hits.