MOI Combo-Set with Shaft Change

[ARL67]

Ok MOI experts, need some advice:

 

In reality I just need to add a 4U to my MOI matched set of Srixon 5-GW, but using a lighter shaft for the 4U.

 

But let's expand that notion and say I am doing an MOI build of a combo set of ZX7 and ZX5  ( ZX7 7-8-9-P and ZX5 3-4-5-6 )

I'm going to use Modus 120 in 7-PW , and Modus 105 in 3-6

I'm using 3/8" increments per club, which would require a 0.5 SWP change per club if building via a SW Scale.

I now have an Auditor Speedmatch MOI device in my golf tool arsenal.

 

I have built 7-PW to a target MOI of 2700 ungripped.

Do I build the 6i with lighter shaft also to 2700 , and same with the rest of the longer irons ?

Or should measure the SW of the built 7i, add 0.5 SWP to that number, build the 6i to that SW number, then measure the MOI of that 6i, then proceed to build 3-4-5 to the 6i MOI number ?

 

 

 

 

[Howard_Jones]

8 hours ago, ARL67 said:

Ok MOI experts, need some advice:

 

In reality I just need to add a 4U to my MOI matched set of Srixon 5-GW, but using a lighter shaft for the 4U.

 

But let's expand that notion and say I am doing an MOI build of a combo set of ZX7 and ZX5  ( ZX7 7-8-9-P and ZX5 3-4-5-6 )

I'm going to use Modus 120 in 7-PW , and Modus 105 in 3-6

I'm using 3/8" increments per club, which would require a 0.5 SWP change per club if building via a SW Scale.

I now have an Auditor Speedmatch MOI device in my golf tool arsenal.

 

I have built 7-PW to a target MOI of 2700 ungripped.

Do I build the 6i with lighter shaft also to 2700 , and same with the rest of the longer irons ?

Or should measure the SW of the built 7i, add 0.5 SWP to that number, build the 6i to that SW number, then measure the MOI of that 6i, then proceed to build 3-4-5 to the 6i MOI number ?

 

 

 

 

I understand the question, but like most others you have an idea that SW or MOI is a parameter to navigate on like this but its NOT and was never meant to be, so lets take a step back and start with WHY DO WE DO THIS ???

Clubs we swing the same "should have" the same resistance, but neither the SW system with flat SW, or MOI matching using progressive SW or a flat MOI is a guarantee of good fit  

A SW matched set (flat SW) has progressive higher resistance as go we longer
A MOI matched set has the same resistance no matter club length.

We actually have 2 points or 2 ends of a AXIS here, and 14 options in the between them....

The "right" way to do this, is IMO to tune up the longest and shortest club on the set, without using measure tools for MOI or SW at all. Simply navigate by the most precise instrument available, YOU THE PLAYER and your "human scale" who has a return value system who say "too little, too much, almost there, just perfect"...

After those 2 clubs is tuned up, its time to bring them to the works shop and measure what values they have for both TOTAL wgt and SW/ MOI.

Now we draw a slope between those 2 clubs, and plot in the values for the others to belong on that slope.

End Note
We should do it this way, even if its a set 4-PW we "think" we swing the same, so even if MOI matching is the idea we follow, do yourself that favor thats you make 2 test clubs (both ends of the set) instead of just one, why typical is 7-9...

The thing is, even if we think we swing all clubs the same, ALL of us is grown up swinging SW matched sets who demands more power the longer the club is, and thats means many of us has it in the bones that a "long iron" always gets a little extra power vs a short iron, and that also means resistance or MOI should be adjusted for that, and the "2 club system" (shortest and longest), will automatically take care of that, we dont even have to think about it, the works shop datas we see when done will tell whats right for us or not, so just do that test, and you have all your answers for whats specs thats the right one for you to use.

The TOOLs we have SHOULD NOT be introduced here before we have tuned up 2 clubs that works, simply because '"values" often misleads us and gives us a certain expectation to something, so leave this instruments out of the "fitting area" they can never compete with 
the "human scale" or tell us where to go to improve impact, so they only disturb us before we have 2 clubs already tuned up so they work for us.

PS! a huge drop in shaft wgt from "short to long" like your plans seems to be, indicates you might need to treat this like 2 separate groups of clubs. I a BAG we typically have a shaft weight progression from one "group" of clubs to the others, and we typically RAISE resistance from group to group (same reason as described above, we use more power the longer we wants to move the ball, thats "human nature", so even a MOI matched BAG DONT have the same MOI on all clubs, but might have the same MOI within each group of clubs.

Irons LOWEST MOI,
Hybrids Higher than Iron
Woods higher than hybrids
Driver - Highest MOI in the set
Wedges - in the area of the driver.

In the end, EACH CLUB is really a fitting object of its own, so the "best short cut" is to build and tune up the shortest and longest, and then draw YOUR slope between those so you get youir target numbers to build to.

[Curious]

Similar to this then?

Design Notes - Heft: swingweight and MOI p6 (tutelman.com)

[Cwebb]

Are you aware that the Modus 105 has a very different bend profile compared to the the 120 version?  Or was this just an example for discussion of weight differences?

Edited March 30, 2021 by Cwebb

[ARL67]

^^^ I'm only speaking hypothetically, just a discussion on mixing shafts of varying weights.

 

I will follow Howard's advice and build by feel -> lead tape is our friend while we experiment  👍