Why are we still using Swingweight?

[Julius]

5 hours ago, Dave Tutelman said:

Julius, I'm an engineer, so it is a little hard for me to completely drop the technical stuff. But the first page of my web article about swingweight and MOI, while somewhat technical, avoids the math and keeps the explanation to words and pictures. You might find it a good introduction. Or maybe not.

If you get through the first page, continue on until you are in over your head. No matter how far this is, you are going to learn a bunch about the topic.

hi Dave - well, that was a lot!! I visited your site, fascinating stuff there.  Thank you for sharing that.  Realistically it is all much more than I would have ever thought about when I am playing the game.  I see you have a lovely family and an interesting life, you are blessed to have all of that AND be able to play this game until your current age - truly blessed!!  Thank you again for sharing. 

[Henri-Martin HORN]

I used a Titleist TSi3 drivers 10° with a Mitsubishi Tensei Blue 55gr regular flex shaft.  Since I am 65 years old, I switched from a S flex to a R flex recently.  Furthermore, I did a fitting with Titleist recently and I kept the standard configuration because it works well for me (suggested by Titleist).  This driver typically comes with a standard swingweight around D3 with a shaft length of 45.5 inches.  This is also my personal preference to match my swing characteristics.  If I decide to modify the swingweight in the future, I will either go to a lighter grip to increase the swingweight or to a heavier grip to increase the swingweight. 

[JohnnyGibble]

On 5/7/2024 at 4:21 PM, revkev said:

This is of interest to me - I’m having issues with a set of irons that I just can’t hit straight - I’m blaming the shaft for being “too light.”  I wonder though. Maybe it’s the lie angle, the kick point or something else. And before you guys point the finger I have two other sets of irons where my dispersion is around the target rather than 40 feet left of it.

Had this same issue with a “fitted set” of Mizuno irons JPX 923 hot metal HL. Lie angles were suppose to be 1 degree flat. After doing some lessons my coach asked if I was playing them long. Got them checked and they were all .5 inch long and lie angles were all 3-4 flatter than they were suppose to be. Got them shortened and lie angles moved back to standard been better ever since.

[mike4hsc]

I am currently trying to figure out what shafts to use that will help my game more. With a slower swing speed, I’ve dropped to a senior shaft instead of a regular shaft as I fall on the low end of a regular. With the drop in grams of the shaft it feels like I’m able to swing the club more freely and the club face square. I feel you should go and get fit but also mix in experimenting with what will work with your game.  As we all see on tv, there’s more than one way to being successful.

[Jean D]

I play at 116.2cm (45.75" ) and may shorten my grip to play at 114.3cm (45") as I continue to test the Autoflex Dream 7 shaft.  For me, it's a balance between being confortable (I am 198cm/6'4") and the ability to hit with distance and good control. I have the comfort bit...now I just have to work on the rest  

[AJWilke]

I’m 6’1” and play a 44” driver. Reducing the club length to 44” is the best improvement I’ve made in my game. It has given me much more control and put me back to constantly being in the fairway. Also, my Arccos data shows I haven’t lost any distance, actually gained a few yards. I think this has to do with the ball traveling farther in the fairway than in the rough.

[bens197]

6’2” playing 45.5” in both my G400 and TSi3. 
 

In college I was 44.5” and there are days I consider shortening it up. If I’m having a wonky swing day I usually choke up to make up the difference and get better contact. 
 

Bonus of having the reduced taper Lamkin Sonar grips. 

[Marty2shanks]

6-0” playing 45” and typically grip down slightly.  I have become a big proponent of slightly shorter drivers in a stiffer shaft and then swingweight the head to get to D3-5.  This often slightly softens the shaft.  So if your swing speed says you should play a regular flex, play a stiff flex and add some weight to the head to get to D3-5 which will have the driver play softer.

[Vince Lake]

I’m currently playing an “Alta” blue 55gram stiff shaft that measures 45.75” in a Ping head. (According to Ping’s website because the shaft is Stiff it actually is a 60 gram shaft . Initially I was a little concerned about the length, however the additional length works well !

[Krls032022]

45” Cobra Aerojet Max

[Vegan_Golfer_PNW]

I agree with the OP. I have an MOI matched set and don’t see that changing. Love it in my irons. Every club truly feels the same. Now in terms of driver and woods that is different for me. For driver, depending on shaft, my sw is around d0-5 although total weight is only like 10g difference. Kbs td shaft (70g) really feels more head heavy even when at the same length (choked down) to my Ventus black 6x (44.5”). 

[Ralph Findlay]

Hi all, 

Have recently swapped my 5wood Sim Ti and 3wood Sim2 Ti shafts and found that the extra length when put on the 5wood is a good move and game changer..for me! 

I play off 5.8 WHS; I'm 65 years young. My driver is a standard length, what M5. 

Hope this helps.. 

[revkev]

Oh my - lots of technical stuff here which is quite interesting. I did go for my iron fitting at golftec today.

Besides the fitting we looked at what I actually had in my Srixon irons as well as the D7 forged. It turns out that the Srixons are significantly too flat for me which would lead to pulls - and the few shots that I hit with that seven iron pulled significantly just as I miss them on the course.

 

The D7 forged were shorter, better launch but not great, pretty nice dispersion though.

 

I found 2 irons that would be a significant upgrade over the D7 forgers - Taylor Made 790’s and Ping 430’s both at 62 degrees, 1/2 shorter than standard, 65 grams, 1 degree flat for that length - 21 degree launch, 44 degrees angle is descent - 12 yards of dispersion, 146 yard carry - run out around 153 yards - I’m thought about fir a few hours and pulled the trigger on the Pings - I loved the way the shaft felt and really did not gave any significant misses with it - I hit one last one at the end of a 90 minute fitting - 104 mph ball speed, 5500 spin rate, 22 degree launch, 149 yard carry, 43.4 angle of descent, slight draw, 1 yard right of target, about as good as I’m going to get at 67 years of age. 

 

 

[Dweed]

My ping G400 SFT is standard length, 44.75 or 45 I think. I tinkered with shorter shafts on my Adams FAST Speed 12 but never felt there was any increase in accuracy and certainly not distance. My swing speed is getting slower as I age so I'm concentrating on tempo to obtain as much accuracy and distance that I'm allowed.

[skfox]

I could not disagree more. While getting fit for my pxg irons a few years ago that has a changable weight in the head initially I hated the irons. When the fitter added more weight to the head I all of a sudden could swing the club and loved the irons. Then when I got my irons for months I could not hit them to save my life. I went and had the swing wieght tested and found out whoever built my actual irons messed up royally with which weights were put in the heads. Once i had this fixed it was like having a new set of clubs. 

[Donn lost in San Diego]

On 5/8/2024 at 1:53 AM, obevz said:

I gave up on Swing Weight around 2005...when I bought my MOI machine from Golf Mechanix...has never let me down.

How much $$ is a MOI machine?  What does it do, or measure?

[Donn lost in San Diego]

Is this the ultimate rabbit hole?  I did sort of wonder, how did the physical scale for measuring swing weight come to have a fulcrum where it does?

Looks like I have to go to tutelmans website.  I would like to know why the shaft of my 2012 era Adams 3 wood, a blue Matrix Radix, loves me more than most other shafts I've touched.

[Donn lost in San Diego]

On 5/9/2024 at 11:59 AM, Dave Tutelman said:

We're very much in agreement here, BigBoiGolf. Even to our opinion of what Russ Ryden is doing. Just a few things I'd like to point out.

A lot of the discussion -- too much in my opinion -- is centering around the fact that 14" is not a pivot or fulcrum for anything real. While true, that completely misses the point. The inventor of swingweight, I am almost sure, picked 14" empirically, because it simulated moment of inertia across a wide variety of clubs. That, and not any physical reasoning, is behind the number 14".

If you look at the graphs I mentioned in my previous comment, you will notice that swingweight and moment of inertia track very well against one another, if all you vary is head weight or overall shaft weight or club length. If you consider swingweight to be a "cheap and dirty" way to measure moment of inertia, the errors are less than 10% for each of those club properties. (That relationship falls apart completely when you look at grip weight. We'll get back to that in point #3 below.) Until the 2000s, it was quite expensive to actually measure MOI, which cannot be done statically. (Well, either expensive or tedious and math-intensive.) So a swingweight scale was a remarkably good shop tool for getting an approximate MOI match. Very few of the clubfitters who used the tool every day knew that, but physics and history strongly suggest it is true.

With 20:20 hindsight, here are a few things we need to think about when we think about swingweight:

1. I have shown elsewhere that a really good MOI match can be obtained by doing a swingweight match with a sloped swingweight of a little over one point per inch of club length. This gets much closer to a true MOI match than a straight swingweight match does.
2. All of this -- the origin of the swingweight scale, the sloped swingweight match, etc -- depends on varying length and clubhead weight only. There is a second correction for changes in shaft weight. Anything else simply does not fit the model, and can give nonsense results if you do them to match swingweight. That includes different weight grips, counterweighting, lead tape in the middle of the shaft, etc. The talk about a D-0 telephone pole is no more than a joke based on this truth.
3. If you think about when swingweight was invented (the 1940s), there was not much choice in shaft weight and even less in grip weight. So swingweight worked fairly well as an MOI surrogate for the clubs you could build back then. With today's ability to play with shaft weight profiles and grip weights, swingweight is no longer a reliable surrogate for MOI -- unless you are careful not to use those "knobs" to adjust your clubs.

Well Dave, I just read your "short" life bio on yr site.  That's quite a life.  Kind of parallel to Karsten Solheim, tho Karsten never actually earned a college degree.  It touches me a bit.  I had 2 cousins (Rosenberg) who were EEs, worked with Einstein at Princeton on occasion.  Einstein once did his Charlie Chaplin imitation in his living room for my great aunt in Trenton or Princeton.  And in my generation, I was born in 54, another cousin at Bell/Lucent did research work on gallium chips.  

[BigBoiGolf]

14 hours ago, Donn lost in San Diego said:

How much $$ is a MOI machine?  What does it do, or measure?

A GolfMechanix Auditor Speed Match v3 is $650, it uses a constant spring force to measure the moment of inertia, or 'First Moment' of a golf club at its grip cap.

Moment of Inertia is a required parameter in calculating Angular Momentum, where Angular Momentum L is the product of Moment of Inertia I and Angular Velocity ω. We require these values due to the nature of how heavily rotational the golf swing is.

https://phys.libretexts.org/Bookshelves/University_Physics/University_Physics_(OpenStax)/Book%3A_University_Physics_I_-_Mechanics_Sound_Oscillations_and_Waves_(OpenStax)/11%3A__Angular_Momentum/11.04%3A_Conservation_of_Angular_Momentum

[Donn lost in San Diego]

7 minutes ago, BigBoiGolf said:

A GolfMechanix Auditor Speed Match v3 is $650, it uses a constant spring force to measure the moment of inertia, or 'First Moment' of a golf club at its grip cap.

Moment of Inertia is a required parameter in calculating Angular Momentum, where Angular Momentum L is the product of Moment of Inertia I and Angular Velocity ω. We require these values due to the nature of how heavily rotational the golf swing is.

https://phys.libretexts.org/Bookshelves/University_Physics/University_Physics_(OpenStax)/Book%3A_University_Physics_I_-_Mechanics_Sound_Oscillations_and_Waves_(OpenStax)/11%3A__Angular_Momentum/11.04%3A_Conservation_of_Angular_Momentum

Since I am not an engineer (smoked too much pot), is the MOI device similar to a CFM device?  And,  . . . . why isn't CFM in these discussions much?

[BigBoiGolf]

5 hours ago, Donn lost in San Diego said:

Since I am not an engineer (smoked too much pot), is the MOI device similar to a CFM device?  And,  . . . . why isn't CFM in these discussions much?

It's only similar in that both a CFM and an MOI meter will read oscillations using a laser. A CFM cannot convert frequency to MOI because it's not referenced to anything, it's merely measuring from an arbitrary clamping point the # of oscillations a club has per minute, where an MOI meter uses a known-spring force and measures the period of an object horizontally to minimize the impact of gravity.

CFM isn't in these discussions because the way that people use CFM and/or instrumentation is in an arbitrary and capricious manner, much like swingweight. That, and a CFM reading isn't really going to tell you much, whereas instruments like MOI meters use standard SI units of measure to represent tangible real-world differences.

CFM isn't of much use now that people like Russ Ryden profile shafts with EI curves at every inch, along with other measurements that supercede the lower resolution measurements of shafts that older 3 point graphs/databases use to use.

[Donn lost in San Diego]

16 hours ago, BigBoiGolf said:

It's only similar in that both a CFM and an MOI meter will read oscillations using a laser. A CFM cannot convert frequency to MOI because it's not referenced to anything, it's merely measuring from an arbitrary clamping point the # of oscillations a club has per minute, where an MOI meter uses a known-spring force and measures the period of an object horizontally to minimize the impact of gravity.

CFM isn't in these discussions because the way that people use CFM and/or instrumentation is in an arbitrary and capricious manner, much like swingweight. That, and a CFM reading isn't really going to tell you much, whereas instruments like MOI meters use standard SI units of measure to represent tangible real-world differences.

CFM isn't of much use now that people like Russ Ryden profile shafts with EI curves at every inch, along with other measurements that supercede the lower resolution measurements of shafts that older 3 point graphs/databases use to use.

Is it safe to say that CFM numbers are a useful tool when comparing shafts?

 

And here is lolapalooza: how do makers measure the ovaling effect?  Do they use hi power lasers?  I was fascinated when I got back into golf around 2015 with the UST Recoil shaft where they talked about taming the ovaling change of shape of a seemingly round shaft.

[RetiredBoomer]

I make no pretense of expertise on the matter, but back when we bought nine matching irons and four matching woods, often also matching,
we seemed to talk about swing-weight a lot more.
This, I'm sure, predates many of the younger forum readers.

In this era of piecing a set together, I honestly don't hear about it that much.
I imagine matching four and five brand sets would require a lot of custom work.

[BigBoiGolf]

19 minutes ago, Donn lost in San Diego said:

Is it safe to say that CFM numbers are a useful tool when comparing shafts?

No. CFM doesn't give you any tangible number other than oscillations measured. If you wanted to compare golf shafts, you would compare them on their EI charts, torque values, shaft stiffness in set, weight, balance point, etc. CFM will give you none of this.

21 minutes ago, Donn lost in San Diego said:

And here is lolapalooza: how do makers measure the ovaling effect?  Do they use hi power lasers?  I was fascinated when I got back into golf around 2015 with the UST Recoil shaft where they talked about taming the ovaling change of shape of a seemingly round shaft.

You can find out how it's measured at https://www.golfshaftreviews.info/ or https://www.golfmechanix.com

[Donn lost in San Diego]

Is this correct:  Swing weights of The Same Shafts in my set should be close to each mother, but swing weight itself does not tell me Where the various Segment flex?  I can love a certain C-9 and hate another C-9?

 

In general, should swing weights increase a small amount as I go from a longer shaft 3 iron all the way to the much shorter wedge?  Like from a C-5 3 iron, to C-7 or C-8 at the wedge?  Since we want more loft on the shorter club, even tho the face has more loft, we also want the shaft to give it a small boost too? 

[Donn lost in San Diego]

4 hours ago, BigBoiGolf said:

No. CFM doesn't give you any tangible number other than oscillations measured. If you wanted to compare golf shafts, you would compare them on their EI charts, torque values, shaft stiffness in set, weight, balance point, etc. CFM will give you none of this.

You can find out how it's measured at https://www.golfshaftreviews.info/ or https://www.golfmechanix.com

Jiminy Crickit!  That review web site could keep me busy reading the rest of my life.  I might spring the $12 for a 1 year non-pro subscription.  Shafts are more fascinating than club heads.  I bet that a touring pro could at least make the cut using Ping Eye 2 on today's fitted clubs.  My best shaft is on a 12 yr old Adams 3 wood.  I am going to bring it when I get my newish driver fit for a new better shaft, now that I am post 3 arthritis surgeries and can swing a little faster.

[RetiredBoomer]

I have a swing weight question.

I really love the basic specs of Pings current model G Le3 WOMEN'S fairway wood clubheads,
but they swing at C1

and I'm afraid that even with men's shafts and grips, they still won't get up to the C9 / D0 area which I find to be the acceptable minimum.

Is there an effective way around this?

[BigBoiGolf]

11 minutes ago, RetiredBoomer said:

I have a swing weight question.

I really love the basic specs of Pings current model G Le3 WOMEN'S fairway wood clubheads,
but they swing at C1

and I'm afraid that even with men's shafts and grips, they still won't get up to the C9 / D0 area which I find to be the acceptable minimum.

Is there an effective way around this?

Women's clubs are generally the same headweight as men's clubs, the reason they have less MOI is because they're typically 1 inch shorter than Men's clubs and also using lighter golf shafts.

You can just add lead tape or increase club length to get to where the swingweight is, but as I and others have explained in this thread, swingweight is not going to help you because you can have different clubs reach the same swingweight but have different MOI values.

[RetiredBoomer]

56 minutes ago, BigBoiGolf said:

but as I and others have explained in this thread, swingweight is not going to help you because you can have different clubs reach the same swingweight but have different MOI values.

I'm concerned about the clubs feeling right.

Having lofts and lie angles with which I can work takes care of my impact quality concerns if the clubs feels right.