What is MOI?

Question

What is MOI in drivers? What advantages?

Answer 1

I answered this question a few months ago. My answer verbatim is below:


MOI = Moment Of Inertia

From space-electronics.com: "Since March 1, 2006, the United States Golf Association (USGA) imposes a limit on maximum moment of inertia (MOI) of golf clubheads. The limit is on moment of inertia around the vertical axis through the clubhead center of gravity (Izz). Since April 11th, 2006 the maximum allowed MOI is 5,900 g-cm² with a tolerance of ±100 g-cm²."

The link to the excerpt above is http://www.space-electronics.com/KnowHow/clubhead_optimization.php

As it relates to what MOI does to a ball when struck, this is from the February 2, 2007 issue of "Golf World" (page 10, 3rd paragraph):

"While it is true a clubhead with a high MOI will twist less on a mis-hit, the greatest benefit is that it reduces the energy lost on such hits. As a result, off-center strikes will go farther, but not necessarily straighter, especially if the clubface is not square at impact."

In layman's terms, a higher the MOI, the greater the sweet spot. But it's still up to the golfer to keep it straight.

Answer 2

MOI = Moment of Inertia
A physical property of a solid. Moment of inertia is a property that describes the ability of a solid to resist motion, acceleration, bending, twisting, rotation, etc. Physics.

In golf, at impact the club and ball go through an inellastic collision - both club and ball deform and some of the energy is lost in the form of heat and noise. When a ball is mishit, a force is put on the club face that tries to rotate the club face. With a higher moment of inertia in this case, it takes more force or a bigger mishit to turn the club face.

Basically, the higher moment of inertia all the golf commercials boast about are saying you can make a terrible swing and still make a good shot. In reality, we're not talking huge distances, but fractions of an inch. A crappy swing is still a crappy swing. You just get a little more forgiveness with these new clubs.

Answer 3

Moment of Inertia

See the wikipedia def here:

http://en.wikipedia.org/wiki/Moment_of_inertia

Laymans terms - the higher the MOI, the more resistant to twisting and less energy loss - which means straighter and longer shots for you on SLIGHTLY off-center hits.

On really bad swings and shots a high MOI isn't going to do diddly squat! The old arrow / indian - fiddle / fiddler paradox comes into play once your swing starts to get too funky...

Answer 4

MOI stands for "Moment of Inertia". A higher MOI reportedly reduces the yardage loss on mis-hits and may result in longer, straighter drives on good hits. The high MOI makes the club more stable at impact, so if you hit if off center, you won’t lose distance. These mis-hits should also be straighter, resulting in fewer out of bounds shots.

Answer 5

Moment of inertia-resistance to twisting on off center hits,so
essentially more forgiving .

Answer 6

http://golf.about.com/od/faqs/f/moi.htm

Answer 7

it means "me" silly.