Marketing claims have not changed much over the years. Here is an add from 1962 with lots of science regarding this remarkable new ball:
Driver Mizuno ST190 9.5* / Paderson Ballistic KG70-D40. Hybrids: 3 and 4 Rogue / Steelfiber HLS980. Irons 5 through Wedge PXG 0311 / Steelfiber i110. Wedges 50*, 56*, 62* MacDaddy 4 / Steelfiber i110.
That trampoline analogy is outdated because most major OEMs use some form of Variable Face thickness. Even Tom Wishon has weighed in on it. https://wishongolf.com/2011/09/08/whats-the-big-deal-about-a-variable-thickness-face/
As for your analogy of a muscleback being like bouncing a basketball off of concrete, that seems way off. Because I do not know of many driveways or basketball courts that have a sweet spot. Golf clubs however do have sweet spots. And club designers know that moving weight from the back of a club to the perimeter can reduce twisting at impact thus stabilizing the club head. A more stabilized club head at impact means less lost energy when shots are hit further away from the center of gravity. So higher M.O.I. and variable face thickness makes for a club that allows for a larger margin of error....IE more forgiveness.
I guess it comes down to if you live in the WRX'er world there is no difference in musclebacks or cavitybacks because true WRXers never miss the sweet spot and achieve this feat with swing speeds that most professional golfers can only dream of. And they also believe and can prove beyond a shadow of a doubt that new golf technology is as mythical as a unicorn, and is pure marketing BS.
However in the real world, some of this technology does actually help players quite a bit.
Just counting the top 20 players in the current world golf rankings. 13 of them play blades.
Driver: PING g410 plus 9* with even flow black 75x
Fairway: PING g410 16.5* Tensei orange 70x
Hybrid: PING g410 19* Tensei blue 85x
4iron: PING iblade Project x lz 6.5
5-PW : PING blueprint Project X lz 6.5
Wedges: PING glide forged 50/54/58 Project x lz 6.0
Putter: Odyssey stroke lab
This stat could be argued to support both camps, no?
Blade camp - 13 of the top players in the world are using blades.
Cavity camp - 7 of the top 20 players in the WORLD need the help of cavity backs.
I don't necessarily agree that its being a 'top wrx'r blades are life' kind of guy to question whether SGI irons are as forgiving as claimed - it's not unreasonable to question the manufacturers when we haven't got the data to support their claims
The variance shown in Mark Crossfields most recent test alone show that the question itself is reasonable
Driver - Titleist 910 D3 10.5 Motore Speeder VC6.13 wood - Titleist 910 F 15 Motore Speeder VC 7.1Hybrid - Titleist 910 H 19 Diamana Kai'li Irons - Mizuno MMC FliHi 3 Iron - KBS Tour stiffIrons - Mizuno JPX 919 Tour 4 - PW KBS Tour stiffWedges - Titleist SM7 53 & 60Putter - Yes! Callie
Do you have data, say from an iron byron to back that up??? Cause all the data thats out there that i see says the opposite.
moving the weight to the perimeter of the head can increase the resistance to twisting yes. BUT BY HOW MUCH??? also what happens to spin, ball speeds relative to a sweet spot hit? At the end of the day its the dispersion circle that matters...theories are great. Perceptions can deceive. Preconceived notions and bias confirmation needs to be thrown out.
From the mouth of babes
Surely you cannot treat the clubhead in isolation, particularly as it is not swung on a linear plane and is attached to a shaft.
The shaft weight, shaft torque and where weight is positioned in the shaft all must impact on overall club MOI or am I missing something?
The shaft is not involved with impact. It influences how a human swings the clubhead, but nothing more.
For practical purposes I believe that you are correct, the clubhead can be considered a free body in space for calculation. However the shaft does have some influence on impact however negligible it may be. I think that I saw some data somewhere that quantified it. LOL don't remember where now and it does not really matter anyway...
The discussion is focused on CLUBHEAD MOI and not club MOI (fitting perspective). Everyone here is aware of the marketing we have been fed for years starting with the first cavity back head that came out. We just would like to see SOMETHING verifying the amount of WHATEVER we are supposed to be getting. Those in the CB camp seem to think all of those in the MB camp are "maroons" because they don't just fall in line. I mean, I am at this very moment trying fitted irons with a clubhead MOI that is near 70% MORE than what I am used to playing. One would think that I would be seeing considerable accuracy gains due to the added tech. However, I am not so far with 4 rounds on the clubs. I am committed to chase this rabbit for at least a month or so, just to be fair. So far, the one thing that I CAN attest to is that I am having REAL ISSUES getting the ball to spin enough to stay on the green. Shots are high, but they just want to keep on rolling unless I hit a boggy spot. Time will tell.
Just to be clear, I have a couple of sets of players CBs that I have no problem playing. Their MOI ratings are basically the same as my MBs though. So I got these to actually SEE what high clubhead MOI would do for ME specifically.
The Golf Shaft’s Influence on Clubhead-Ball Impact Dynamics †
William McNally 1,*, John McPhee 1 and Erik Henrikson 2
1 Systems Design Engineering, University of Waterloo, 200 University Ave. W, Waterloo, ON N2L 3G1, Canada; [email protected]
2 Ping Inc., 2200 W. Peoria Ave., Phoenix, AZ 85029, USA; [email protected]
* Correspondence:[email protected]
Australia, 26–29 March 2018. Published: 13 February 2018
A long-held assumption in golf research is that the driver-ball impact is accurately modelled as a collision between two free bodies, i.e., the clubhead is not attached to the shaft. The purpose of this work was to examine the validity of this assumption using multibody simulation and motion capture technology. Ten elite golfers were recruited to participate in a motion capture experiment to validate a Rayleigh beam model of a flexible club. Using the six degree-of-freedom motion of the grip as an input to the model, the simulated shaft deflections showed good agreement with the experiment. An impact model based on volumetric contact was integrated with the flexible club model and was used to compare the launch conditions of free-body and full-club impacts. Analysis of the launch conditions revealed that the shaft creates a stiffening effect that resists clubhead rotation during contact, corresponding to an increase in ball speed and suppression of the gear-effect relative to free-body impacts. The results demonstrate that shaft dynamics cannot be treated as negligible when evaluating driver impact mechanics.
The rest of the article shows the science behind it...
Again, the discussion is about CLUBHEADS, not shafts or fitting.
When club designers are designing a clubhead all of this is taken into account. The general club design takes into account the physics of a golf swing. Yes choice of shaft can affect things quite a bit. On standard length irons, if all of your irons were the same MOI then they would all be different swing weights. Club designers know this and it is factored into the design of the club.
And this is also why some of of the youtubers like Crossfield and Shiels are missing so much of the point when they claim to be doing a "fair" comparison. Especially with irons you can't just assume that the same shaft that you were fit for in one club will also be the optimum shaft in a club that is designed to act and behave completely different.
I have played musclebacks and blades, and I generally get my best numbers when playing a softer flex heavier shaft in a blade style iron. Yet with most cavitybacks I see better numbers with a lighter stiffer flex shaft. Yet with hollow design distance irons I tend to get my best numbers with middle of the road weighted shafts(110g) and a stiffer flex. Every individual's mileage may vary, but the odds of the same shaft being optimal in 2 radically different designs is extremely low.
I guarantee that if you go into a fitting with an open mind, and a desire to try to find the right shaft for each club design you hit, the different deigns will show different characteristics. Then it is up to the golfer to decide which is better for his game.
I don’t see how you can discuss the MOI of a clubhead in isolation when the shaft has a direct impact.
Simple, you take two different clubheads and use the same shaft, grip and balancing. You build them the same, balance them the same, fit them the same so that the ONLY difference is the clubhead itself.
I pretty much agree...and can validate the same from personal experience. Now if the OEMs published the data they have for full club MOI with different shafts at different swing speeds we might have some chance of picking the optimum combination to suit our own idiosyncratic swings. Until then, as you say it is down to hitting as many clubhead and shaft combinations as possible and picking the best based on results.
I’ve had 3 fittings over the years and every single time my best results have been with MBs paired with S300s. Current C-Tapers are a bit of an experiment based on nothing more than the step less shafts I’ve played just seem to be ‘smoother.’ Early on to really say how it’s going to pan out, but dispersion does seem to be a little bit tighter than the S300s.
You are obviously one of the very few who understands that MOI cannot be focused solely on the clubhead...unfortunately most do not see it the same way 👍
May be, but I know what two shafts work for me and have turned down a manufacturer’s option if their iron head does not include my shaft preference.
While their paper does show the shaft affecting impact, it is a fairly insignificant amount. Roughly 2% - 5% ball speed in the region where you would want to hit the ball. The greatest influence the shaft has is for (logically) shots hit near the hosel. The free body model under predicts ball speed by a little more than 7% or so. Those strikes were over 20 mm away from CG. Basically the way to think about it is that real clubs with shafts are more forgiving if you miss hit the driver badly high, heelside. The study was specifically performed for drivers, but should apply to irons as well although the magnitude of the effect is unknown (could be larger or smaller).
I agree that they could not conclude what the magnitude of effect the shaft has on launch conditions only that it cannot be treated as negligible. To me, it is obvious that the shaft affects how much the clubhead twists at impact. Although I can swing a lightweight graphite shaft a lot faster than steel, I cannot square the clubface at impact...and that is all me. However, if I deliver the clubface square at impact but the strike is off-centre (say toe-side) the clubface is going to twist open to a far higher degree than the same strike with a lower torque steel shaft.
Other papers I have read also suggest that increasing overall golf club MOI by moving mass within the shaft or by adding or decreasing weight to the clubhead, reliably decreases clubhead and ball velocity. Again, the magnitude of change in velocity as a consequence of altering MOI cannot be reliably quantified.
As I said earlier, there will be an optimum combination of clubhead and shaft for every golfer and the only reliable way of finding it is to test as many as possible until you fall upon the combination that works for you.
PS I found it interesting that they found that maximum ball speed with driver is delivered by strikes that are slightly off-centre and towards the toe. This is my experience too where my BB Alpha has a ‘hotspot’ in this location.
I found that final bit interesting as well. Thanks for posting that paper. Always nice to see some science rather than the typical deluge of marketting.
I thought marketing was the new science? :-)
Treat yourself as if you were someone you are responsible for helping. Jordan Peterson
Too much sanity may be madness and the maddest thing of all is to see life as it is, and not as it should be. Cervantes
In golf, the human mind has much higher capabilities to screw things up than the physics has to make things better. Unknown
Nah, just the same old shell game repackaged every decade ad infinitum (no pun intended).
How can you discuss club heads without the influence of the shaft? I bet everyone taking part in this discussion takes torque into consideration when choosing a shaft. Why? Because it affects club head performance.
I could be wrong but i think the point was assuming shafts are the same so we can isolate just the clubheads.
1.4 Smash Factor, versus today’s 1.5. Wow, equipment has improved by a whopping 7% over the past 60 years. Better roll that ball back Lol!
The shaft doesn't really affect how the clubhead performs. This is especially true where irons are concerned. Very insignificant. However, the shaft significantly influences how a human swings the club. The feel, closing the face properly, speed, etc... are important considerations when choosing a shaft.
Thats not true really either, shafts can effect toe droop, how the head interacts with the turf, also a shafts torque needs to marry up with a heads moi. This subject is getting sidetracked 😂
Toe droop is not a clubhead performance characteristic. Torsional shaft stiffness needs to match up with MOI and how a player releases/closes the face, but that is a whole club performance characteristic not clubhead alone. Finally, while there is a slight stiffening of the clubhead resistance to twisting due to the shaft which impacts turf interaction, variation in that impact between different flex, torsional stiffness, and shaft design would be unmeasurably small.
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