Monday, April 1, 2013

The Road to Golf Club Fitting Nirvana - Part I


Over the years I have delved quite a bit into clubfitting in hopes to find the best answers to equipment. We have looked at MOI matching, lie angles, lofts, shaft lengths, shaft bend profiles, grips, cavity back vs. muscle back designs and a host of other aspects about equipment design and how it fits the golfer. Now, I am getting into MOI Balance Index.

First, let’s go over the basics of MOI matching/fitting and MOI Balance Index. For those who have read this before, they can skip this post.

MOI Matching/Fitting: Typically when MOI is discussed with golf clubs it is with reference to the club head. What we are referencing here is the MOI of the entire golf club. We use total club MOI to help determine the heft of the club. Swingweight does the same thing, but there are many parts of swingweight that are faulty and do not accurately depict the heft of the club. That and swingweight is not a scientific measurement while MOI is a scientific measurement.

For a bit more specific details on total club MOI, I would recommend reading the MOI machine manual which can be found here:

But in simpler terms, when we measure the total club MOI we are trying to determine the amount of force required to swing the club. So when we fit for MOI, we are trying to match up the amount of force a golfer applies in their swing with the amount of force it requires to swing the club. When we properly fit and match for MOI, the impact dispersion will improve tremendously.

[image] [image]

The other part that will improve is the ball flight. Although I find this to be more prevalent with the longer clubs like the driver. I have also found that golfers who struggle with topping a shot with a particular club usually have too much heft (too high of a MOI) and golfers who struggle with thin shots tend to have not enough heft (too low of a MOI). When the MOI fitting and matching is complete, the irons and wedges will have swingweights that get progressively heavier as the club gets shorter. It may look something similar to this:

3-iron: D-1.0
4-iron: D-1.7
5-iron: D-2.4
6-iron: D-3.0
7-iron: D-3.7
8-iron: D-4.5
9-iron: D-5.2
PW: D-5.9
SW: D-7.3
LW: D-8.0

MOI Balance Index: What many clubmakers like myself discovered when doing MOI fitting and matching is that while the impact dispersion will noticeably improve, there are still some clubs in the set that do not perform as well. Furthermore, we started to see that the weight of the components of the club (club head, shaft, grip) have different effects on golfers even if the MOI is exactly the same.

I noticed this with a particular customer of mine who’s optimal MOI with his irons is exactly the same as my optimal MOI with the irons (2,725).

For me, I hit the ball better with a 48-50 gram grip, a 108-118 gram shaft and more weight in the head. For my customer, Bill, he hits that same MOI better with much more weight in the grip and the shaft and less weight in the club head.

That is due to the Balance of the club being different and our swings working better with different balances. In my case, my swing works better with the balance of the club being more towards the club head. Bill’s swing works better with the balance of the club being more towards the grip.

This is mainly due to how we start the club down and when we un-cock the wrists. In essence, we are able to generate about the same amount of force in the golf swing; we just go about it in different ways. I have a smoother start down move, more of a ‘float loading’ style of action combined with a later un-cocking of the wrists into impact. Bill’s swing starts down more aggressively and his wrists un-cock earlier into impact.

It is sort of like 2 runners running a 100 meter dash at the same time, but with different ways to getting there. Bill gets out of the gates very fast. I get out of the gates slower, but accelerate more towards the finish line. But in the end, we arrive about the same time.

Whereas MOI fitting and matching greatly helps with ball flight along with horizontal face contact dispersion, MOI Balance index will help provide even more consistency, help with clubhead path consistency and vertical face contract dispersion.

This eventually led to the discussion of club maker Monte Doherty’s MOI Balance Index spreadsheet. This spreadsheet is available to the public at the link below:

(I recommend saving the Excel file first to your computer, then opening it up. If you have 2010 MS Excel, a header will pop-up with a button called ‘Enable Editing.’ You will need to click that button in order to fool around with the spreadsheet. And you can only do that if the file has been saved to your computer.)

There’s a few things that are very noticeably in the spreadsheet. And in part II – I will go over the noticeable parts of the spreadsheet and how to understand how to use it.

For more information on MOI fitting and matching, check out clubmaker Richard Kempton's Web site at



Unknown said...


I've seen that image of the before/after in the past. Is that real??? I mean, is that an image of, say, a single digit handicap's results from MOI matching? For some reason, I doubt I'd see those results with my 12-15 handicap.


Rich H. said...

I would have to ask. From my experience the gains are dramatic even for higher handicaps.


marina jason said...

Interesting information. Its really understandable post.During your swing we never know how much we applied a force on drivers.Now after this post i know how to see the force applied.
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