MOI-Matching 3w to 3i

[A.Princey]

I'm hoping a pro-builder might chime in on this one, but I've found huge success in "MOI-matching" my iron sets, and have roughly attempted to extrapolate the measurement to my 3w with some real success. Using the SW progression down(fast MOI), and general static weight progression down, as clubs get longer, is it possible to get a 3w to play like a long iron? My wedges are D3 and 3i is about C7.5, and if I build a 3w that follows the iron specs of total weight and swingweight, would a 3w that is 2.5" longer than my 3i be close at C5.5 and 30ish grams lighter overall?

[Howard_Jones]

Its not a good idea to match your woods to your irons, we dont swing them the same.

Those attempts ive made where ALL clubs had the same MOI value and "the right" total weight progression has failed.

We need "some" progression of resistance from irons to hybrids, some more into woods, but its very personal how much.

 

My suggestion is, dial in your woods without thinking of your irons at all.

A good start might be to make a chart for shaft weight progression and MOI for each shaft, so with heads, but both of them vary depending on play lengths, so play lengths is the first we have to find.

 

The spread sheets im using is "way to messy" to be shared, since im running all sorts of numbers on them, but you can make your own, since MOI is simply the summary of MOI from each component.

 

Formula for MOI

(Distance x Distance) x Mass/1000) = MOI points as grams Cm2.

 

HEAD WEIGHT EXAMPLE

Example - a 3W with a play length of 43.00" and head weight of 208 grams where COG of the head is 5/8 above the leading edge = net distance butt to COG = 43.00 - 5/8 -2/8 gross grip cap. = 42 1/8 x 25,4 = 106,8 Cm.

 

Now we take ((106.8 cm x 106.8 cm) x 208 grams head weight/1000) and should get a return who say 2372.3 MOI points like this chart example

 

Then make yourself a chart like this where you can change head weight on the green lines so it can be used for all play lengths and head weights needed.

 

SHAFT WEIGHT and GRIP WGT

The formula is the same, but we need the Balance point of that shaft and the grip to get the distance number, and also have to do the math for weight loss in each end from tip and butt trimming.

 

when you have MOI value of each component, just make the sum of them and you have the clubs MOI value.

 

Progression for shaft MOI (to keep resistance the same), goes from about 6 grams like AMT for irons above 100 grams, and down via 5 grams pr inch from about 70 to 100 grams, and then down to 3-4 grams for lighter shafts. (my shaft progression charts uses 5 grams flat but want get shaft MOI dead on, but since BP also vary from model to model, its impossible to make a chart that fits all possible ways to make it)

 

I know it would have been easier for you if i just shared my files, but its to may loose ends we have to make sure is set correct for each calc, and will only cause others to make mistakes, so its anything but user friendly for others than myself, but it should be easy to make it on your own.

 

But...a word of advice, we can run as many numbers as we like on the paper, but that WANT tell us how it feels, so use your own common sense and DONT manipulate head or shaft weight alone to please the paper, because total MOI is not much better than SW values then, we can get there a 1000 ways, and all 1000 will feel difference even if our instruments and spread sheets return the same sum values.

[Howard_Jones]

Since you navigate in SW values, and im trying to introduce you to move to MOI, read this tread where ive posted charts we might use to convert the numbers both ways. https://forums.golfwrx.com/discussion/1793041/adding-counterweight-vs-counterweighted-shafts-vs-sw-values-or-actual-moi

[A.Princey]

That's the thing, I'm hitting everything on a rope to my aimpoint with the exception of 3w at times. When I went heavier and much lighter SW, contact improved and feel was almost there. I've got a little more experimenting to do, but I'm definitely onto something. It could be due to my slight early release too, there's certainly a dynamic effect to the balance of everything

[Howard_Jones]

My bag might not be a good bag for you to make a copy of, but i have a progression from irons to Driver of 50 MOI points others might be up at 150 points. If we now look at the charts in the tread i liked to, 50 MOI points at 44.00" (as my best driver is), is equal to 4.36 grams.

 

Do the slope like it was ALL irons using 1.33 SWP pr inch, then ADD about 4 grams to the head weight on the 3W. Thats very close to the olden days where they used Irons to Woods = plus 2 SWP

[A.Princey]

OK, thanks for the help.

[A.Princey]

I've got 15g in the butt of my 8q3 and about 9g more of lead tape below the grip, and contact, flight and feel are perfect now at 41.5" and an 8g weight in the Gsft head. There's about 9g of tip weight in the shaft as well.

 

I'm very confident there's a perfect SW per TotalWeight at each discrete length. I also believe every club in the bag follows this relationship, and in the longer club is the more important deviations cause issues. Lastly, driver is a completely separate entity and can follow a different trend, the elevated tee, flatter plane and setup changes make it nothing like an iron.

[RichieHunt]

Yes, do NOT match your woods to your irons.

 

The best fitting practice I know of is to get 1-gram strips of HD lead tape and measure the impact dispersion AND the ball flight.

 

We measure MOI *last*. So get your head, club shaft, length, lie angle, etc. all fitted first and then get out on the range and fit the MOI.

 

Get some impact tape (or foot powder spray). Hit 3-5 shots and look at the impact dispersion and the ball flight. Then add 1-gram of weight to the head, hit 3-5 shots and look at the impact dispersion and ball flight. Rinse and repeat.

 

When the impact dispersion gets tighter and tighter you know you're close to your optimal MOI. If it gets smaller and small and then as you add weight it gets bigger...you've added too much weight and need to go back to the weight that produced the smallest impact dispersion. And as you add weight you may very likely start hitting the ball higher because the CoM of the club is changing.

 

Generally, I found that golfers need about 75-100 more MOI units than their irons. So if your irons are matched at 2,600 you'll probably need a 3-wood at 2,676-2,700 MOI. I don't know what that translates to with swingweight though.

 

The other thing I found with MOI matching and fitting is that with the longer clubs too heavy of an MOI for a golfer usually results towards thin shots with the longer clubs and fat shots with the shorter clubs.

 

 

 

 

 

RH

[Howard_Jones]

If we combine this 2 charts, we can move between MOI , SW and Grams

Example a 43.00" 3W and your suggestion 75 MOI points up from irons = 7.grams or 4.1 SWP

 

When navigation on the SW scale we first subtract 1.33 SWP for each inch longer, then add 4.1 SWP

Example longest iron 39.00 and D0 to a 43.00 = 4 inch x 1.33 = 5.32 SWP + 4.1 = 1.22 SWP DOWN from your #3 to your 3W = C8.78

 

If we goes 100 MOI points up on the 3W the closest on the chart is 9 grams who gives 5.3 SWP

4 inch longer using the SW scale to MOI is 5.32 SWP down, then 5.3 up again, who get us back to D0, so the #3 and the 3W would both be D0

...maybe the SW scale aint so bad after all if its used correct....