MOI matching and balance points across set?

[golferdude54]

With fully assembled clubs, would having the same MOI across the set cause the balance point when lying on top of a flat table edge to be uniform? As in the balance point is the same distance from either the clubhead or butt end of grip when lying balanced on a flat table edge?

[Howard_Jones]

NO

It would look (visually) just like a SW matched set.

[Ty_Guy]

15 hours ago, golferdude54 said:

With fully assembled clubs, would having the same MOI across the set cause the balance point when lying on top of a flat table edge to be uniform? As in the balance point is the same distance from either the clubhead or butt end of grip when lying balanced on a flat table edge?

Without getting needlessly clever in the build, I believe the only way to have identical MOI and SW would be through a single length set.

 

I would be curious to hear about how close someone has gotten to a matched set. 

[Stuart_G]

1 hour ago, Ty_Guy said:

Without getting needlessly clever in the build, I believe the only way to have identical MOI and SW would be through a single length set.

 

Yes.  It would not really be possible otherwise IF you actually respect and understand the original swing weight concept.   That defines a very specific MOI progression in the set as the length changes.   It would only be achievable by using manipulations that the swing weight system was never intended to manage.  Not sure I'd personally characterize that as "needlessly clever" - IMO that implies too much credit is being given to the manipulations than they deserve. 

 

Edited June 12 by Stuart_G

[ChaosTheory]

What happens to the balance points in the MBI method?  

[Ri_Redneck]

My irons are MOI matched, but I have never considered the balance point of each club. I can check when I get home.

 

BT

[ARL67]

FYI - If you build an MOI matched set with shafts like AMT ( 3g diff per shaft ), or better yet Ping CWT so I am told ( 2g diff per shaft ) , they will also come our near SW matched.   I accidentally came across this during an MOI build with my first set of AMT Tour Whites.

 

 

 

 

[ChaosTheory]

On 6/11/2025 at 3:37 PM, golferdude54 said:

With fully assembled clubs, would having the same MOI across the set cause the balance point when lying on top of a flat table edge to be uniform? As in the balance point is the same distance from either the clubhead or butt end of grip when lying balanced on a flat table edge?

Here is a thread that contains discussions about MBI matching.  There is a build report on page 4 which shows that the BP moves downward from 6 iron to wedge.  I don’t know if the spread of the BPs is tighter than in a conventional build.

 

https://forums.golfwrx.com/topic/1737032-moi-of-a-golf-club-where-did-it-go/

 

 

[golferdude54]

8 hours ago, Ri_Redneck said:

My irons are MOI matched, but I have never considered the balance point of each club. I can check when I get home.

 

BT

 

Yes, this is what I meant in my initial post, I should've clarified it some more. I didn't mean to say SW matching and MOI matching are the same thing, I meant how does the balance point of each club when fully assembled differs in SW vs MOI matching. 

 

I would appreciate your feedback on that balance point comparison from your MOI matched iron set very much. Please make note if the distance between the balance point off the edge of a flat table and the clubhead or the butt end of grip remains constant or if it changes from club to club.

[Ri_Redneck]

12 hours ago, golferdude54 said:

 

Yes, this is what I meant in my initial post, I should've clarified it some more. I didn't mean to say SW matching and MOI matching are the same thing, I meant how does the balance point of each club when fully assembled differs in SW vs MOI matching. 

 

I would appreciate your feedback on that balance point comparison from your MOI matched iron set very much. Please make note if the distance between the balance point off the edge of a flat table and the clubhead or the butt end of grip remains constant or if it changes from club to club.

I will check mine and report back to you.

 

BT

[golferdude54]

On 6/13/2025 at 2:07 AM, Ri_Redneck said:

I will check mine and report back to you.

 

BT

 

So any reports?

[CTgamer]

It depends how we’re measuring consistency in balance points:

 

To turn a swing weight matched set into an MOI matched set, we have to progressively add head weight to the shorter clubs (roughly 2/3 point increase in SW for each shorter club). That means the balance point will move closer to the head for the shorter clubs. 
 

In a standard SW matched set of irons, balance point gets further away from the hands (but relatively closer to the grip side) as each club gets longer, because longer length of the club moves balance point out more than the decrease in head weight of each longer iron shortens it. 
 

So in an MOI matched set (assuming constant shaft weight) balance points will be more consistent in terms of absolute distance from the hands, but more variable in terms of balance point distance as a percentage of total club length

 

[Golf Pig]

Here's some real world numbers from a set of PXG irons. All shafts are parallel KBS TGI 80 S with standard tipping. The balance point does not stay the same with either build, but what's interesting is the BP progression between clubs in the MOI matched set is pretty much equal. Also note that the balance point as a percentage of playing length is virtually identical whether it's SW matched or MOI matched.

 

Edited June 23 by Golf Pig

[Golf Pig]

Here's the data without grips. Note that SW is measured with the shaft against the 1/8" grip cap compensator on the Auditor scale. The BP progression in the finished MOI set could have been just a coincidence. Although I did weight sort my grips so the total weight of every club was on the same slope. Maybe that explains it.

 

[Ri_Redneck]

On 6/22/2025 at 8:31 PM, golferdude54 said:

 

So any reports?

Sorry for the delay. Vacation travel getting in the way of things. I checked my irons and they all balance at approximately the same distance from the end of the grip.

 

BT

[golferdude54]

On 7/8/2025 at 8:08 AM, Ri_Redneck said:

Sorry for the delay. Vacation travel getting in the way of things. I checked my irons and they all balance at approximately the same distance from the end of the grip.

 

BT

This is very interesting… so one could balance their assembled clubs off a flat countertop and maybe on top of a ruler attached to the surface; see if they are MOI matched based on their balance points without needing to invest in a $600+ machine? 
 

 

[Stuart_G]

On 7/13/2025 at 7:08 AM, golferdude54 said:

This is very interesting… so one could balance their assembled clubs off a flat countertop and maybe on top of a ruler attached to the surface; see if they are MOI matched based on their balance points without needing to invest in a $600+ machine? 
 

 

No.  Balance point alone will not tell you whether they are MOI matched or not.   There are ways to alter balance point that don't all have the same effect on the MOI.  But you can typically get very close approximation w/o the expensive machine.  You could use the balance point and total weight (or just a swing weight scale) to see the swing weight of each club and how it changes through the set as the length changes.  A particular swing weight - length progression can be an indication of a close match to an MOI matched set.   There are some assumptions that go along with that to be usable.  Identical grips, no butt weight added, and reasonably small shaft weight increments (doesn't work for AMT shafts).

 

 

Edited July 14 by Stuart_G

[IC3BURGH]

On 7/13/2025 at 7:08 AM, golferdude54 said:

This is very interesting… so one could balance their assembled clubs off a flat countertop and maybe on top of a ruler attached to the surface; see if they are MOI matched based on their balance points without needing to invest in a $600+ machine? 
 

 

 

I was able to MOI a set of my irons using the a 1.33 swingweight points per inch rule of thumb relative to my preferred matched club. Later verified with an MOI machine that I was within +/- 1%. You definitely don't need the machine.

[Howard_Jones]

37 minutes ago, IC3BURGH said:

 

I was able to MOI a set of my irons using the a 1.33 swingweight points per inch rule of thumb relative to my preferred matched club. Later verified with an MOI machine that I was within +/- 1%. You definitely don't need the machine.

 

1 % might sound good but is it?

 

A tight tolerance with max plus minus 5 MOI points is as example

 

5/2400 moi points = 0.21% off target

5/2700 moi points = 0.18 % off target

 

Thats the level clubs using a Auditor MOI scale should be built to.

 

Just my 2 cents opinion about that, so if we use a SW scale, or the TW/BP method, make sure your measurements is as good as can be, and NEVER include grips during those measurements.

Edited July 14 by Howard_Jones

[IC3BURGH]

31 minutes ago, Howard_Jones said:

 

1 % might sound good but is it?

 

A tight tolerance with max plus minus 5 MOI points is as example

 

5/2400 moi points = 0.21% off target

5/2700 moi points = 0.18 % off target

 

Thats the level clubs using a Auditor MOI scale should be built to.

 

Just my 2 cents opinion about that, so if we use a SW scale, or the TW/BP method, make sure your measurements is as good as can be, and NEVER include grips during those measurements.

 

The numbers were actually much tighter that 1%, but I did think using a nice round small error conveyed a level of accuracy that might help someone save $600. Maybe not...

[Howard_Jones]

10 minutes ago, IC3BURGH said:

 

The numbers were actually much tighter that 1%, but I did think using a nice round small error conveyed a level of accuracy that might help someone save $600. Maybe not...

 

If we did it like it could and should be done, all we needed was a ruler and a gram scale.

 

Build the longest and shortest club in the set, tune head wgt using the "blind test" (too little or to much without a clue about numbers), then draw your personal head wgt slope between those 2 points...

[Noodler]

As noted by @ARL67 , this can be achieved using AMT shafts along with MBI matching, but it is challenging.  I have gotten close a few times.  I have a set of Mizuno MP-H5 heads on AMT black matched at an MOI of 2675 and MBI of 64.  The swingweight from the 4 iron to the PW goes from D4.0 to D5.0 (basically less than 0.25 point change from club to club in the progression).  I also have a set of MP-15 heads on AMT S400 that goes from D2.75 to D3.75  But the absolute closest is a set of MP-25 heads on Ping AWT 2.0 shafts.  From the 5 iron to PW, it's the 3 long irons at D4.00 and the 3 shorter irons at D4.25.