What is MOI?

I’ve been lookin’ for a new driver, and I keep seein’ the word “MOI”. I didn’t know what it meant. Could it be “mammoth outside impound”? Nah, my mammoth hasn’t been towed.  I ‘ssume it’s not the french moi; cuz I haven’t bought it, so it can’t be mine yet. Ol’ Scratch then decided to go to the source of all knowledge: the internet. I’ve learned a bit about MOI that should help ya in purchasing yer next set of clubs.


  • MOI = Moment of Inertia

    Moment of Inertia is an object’s resistance to twisting or rotation along an axis. Think about a skater makin’ a spin on the ice. She starts slow with her arms extended, but as her arms come into her sides, she speeds up. This is cuz with her arms out her resistance to rotation is high and so is her moment of inertia. On the other hand, when she pulls her arms in, her moment of inertia is low, so her resistance to rotation is low.

  • Why does this matter in golf?
    Moment of Inertia
    This shows how moment of inertia affects your rotation

    As all golfers know, when ya hit the ball, ya want to hit it in the sweet spot. But not all of us are pros, so we sometimes hit off center. When ya don’t hit the sweet spot, the head of the club will start to twist. This gives ya a shorter shot, a slice, or a cut. However with a higher MOI, the head will twist less and your ball will go straighter with more force. This is called a more “forgiving” club.

  • MOI in woods

    Even gone to the shop and wondered why the fairways’ head keep getting bigger and bigger? As they get bigger, their MOI increases. Frank Thomas explains, “In hollow metal woods, the weight is all in the shell and as far away from the center of gravity of the head as possible…The forgiveness in these big heads enlarges the effective sweet spot in all directions on the face – up and down as well as side to side.” So the bigger the heads, the more forgiveness on yer mishits.

  • MOI in putters

    In January, Matt Every shocked his fellow pros by appearin’ at the Sony Open in Hawaii with what I’d call a dino-sized putter. The putter is called the Black Hawk by Orion Golf and it has 21,000 MOI (most putters don’t go over 10,000). Don’t think an extremely high MOI means it’s a great club either; too much MOI could hurt your puttin’. Tom Stites, director of product creation for Nike, explains it this way, “It’s not like hitting a driver,” said Stites. “You’re not going to miss a putt a half-inch or three-quarters of an inch off center. A quarter-inch is a pretty big miss on a putt. You’re also not striking the ball with a lot of force. So you probably don’t need something extreme. But a putter with a high MOI that’s not over-the-top should help you make more putts.”

  • Scratch’s conclusion

    MOI does matter, ‘specially if you’re not a pro. Well, it matters for a driver anyway. But don’t rely only on MOI numbers; always make sure that everythin’ about the club fits your body and your game.

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