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M.O.I.???

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Scrap Iron

Scrap Iron

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I know that it stands for moment of inertia but what is it? What does it do? Is higher better? Do I even need to care about it?

I really have no clue about it.
 
Scrap Iron said:
I know that it stands for moment of inertia but what is it? What does it do? Is higher better? Do I even need to care about it?

I really have no clue about it.
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Concerning club heads, it's the ability of the head to resist twisting (specifically on off-center shots).

Easiest way to explain it is this. Hold a pencil in the center parallel to the ground. Now push one of the ends. See how easy it moves? Now, hold it on each end and think about how much more stable it is. That's basically the same premise as perimeter weighting, which creates higher MOI.
 
Gotcha so moi only concerns twisting. Thanks Hawk.
 
This is a very good question and thread with a lot of information.
I could type all day on this one, and will come in and answer in spots with info.

Think of it as the ability to withstand twisting in some aspects. Generally speaking (very general), the higher the MOI, the more it will withstand. Easier way to look at it is with putters. There are many oversize putters that are described as higher in MOI. Line them up and hit golf balls off the toe with them and watch how little the club head moves. Now grab a bullseye putter and do the same thing and watch how much the blade pulls back at impact.
 
Scrap Iron said:
Gotcha so moi only concerns twisting. Thanks Hawk.
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For the most part I'd agree with that, though with putters it's also been mentioned concerning stability in general more often in recent times with counterbalancing.
 
I thank the op for this thread deeply. Ive always wanted to know this. When i bought the dll it bragged alot about m.o.i Good stuff so far look foward to reading more..
 
Was talking to a Nike rep about this and he was saying the original idea behind the SQ drivers back a few years ago was to minimize twisting of the driver head at impact. Especially on off center hits, that square look with the extra weight distributed on the perimeter was meant to help with that. Less twisting will help minimize gear affect on off center hits which in turn produces a higher MOI and creates less penalizing off center hits. You see some of the same ideas (generally speaking) behind the Covert heads as well

Please correct me if I'm wrong someone, this is just my understanding of it and I am still learning.
 
No, that would make sense Brad. I just think people weren't willing to play a driver that looked like that.
 
dcbrad said:
Was talking to a Nike rep about this and he was saying the original idea behind the SQ drivers back a few years ago was to minimize twisting of the driver head at impact. Especially on off center hits, that square look with the extra weight distributed on the perimeter was meant to help with that. Less twisting will help minimize gear affect on off center hits which in turn produces a higher MOI and creates less penalizing shots. You see some of the same ideas (generally speaking) behind the Covert heads as well

Please correct me if I'm wrong someone, this is just my understanding of it and I am still learning.
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To be fair, the original idea can date back long before their drivers (not what you were saying), but that is correct. The square movement was kind of based on that.
 
From Ralph Maltby;

Moment of Inertia (MOI)
The resistance to twisting of any golf clubhead when the golf ball is impacted off-center or not on the center of gravity location horizontally.
 
Am I correct if I think that MOI does not help you shoot straighter or better, it just helps you deliver the same or almost same amount of energy to the ball from the head during impact, so that the head won't twist away.

I mean that you still have to swing correctly, and aim correctly. The face angle and if you are coming inside out, or outside in, will determine the direction and shape of the ball?

With shots where you hit the sweet spot, MOI has very little to do, and with off center hit's it can help you keep the face angle and direction of the head?
 
M.O.I.???

What was the thought process for that super smart woman who developed that special putter for Aaron Baddely? I don't remember the whole story, and I don't believe he is using it anymore, but she explained, and developed, that a low MOI putter was better.
 
Seems like MOI in the club head is similar to torque in shafts? Not really how it's measured (high vs low) but just in terms of resistance to twisting.
 
B33RMoney said:
Seems like MOI in the club head is similar to torque in shafts? Not really how it's measured (high vs low) but just in terms of resistance to twisting.
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But MOI is for off center hits the Torque measurment is a constant it will be the same no matter what head is on the shaft
 
So it sounds like this is extra weighting around the perimeter of the club. I always thought perimeter weighting was for forgiveness and centre of gravity. Does MOI do anything to help the ball go further and does the USGA have some sort of regulations on it?

Thanks for the feedback so far guys.
 
Yes, the USGA has a limit of 5900 grams/cm2 for moment of inertia.
 
Thanks for asking this question...I was doing some research on the TM Ghost SI Putter and the comment was made that it has 6000 MOI. I didn't really know what was being talked about. Now I know!!!
 
mmaynard11 said:
Thanks for asking this question...I was doing some research on the TM Ghost SI Putter and the comment was made that it has 6000 MOI. I didn't really know what was being talked about. Now I know!!!
Click to expand...

The limit is for woods only, with a 100 grams/cm2 tolerance.
 
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