EI Profile and Feel for Shafts

[ajlacombe]

I am an overthinking engineer and have recently gone through some fittings and a lot of shaft experimentation.  I want to find some discussion about the profile stiffnesses and feel.

 

For Butt, Mid and Tip sections - I want to know when stiffness in a section goes up or down, what does it do to feel.  Also combos of stiffness changes in multiple sections.  I am sure it is easier to say if stiffness goes up or down in one section - this will happen.  But then when you change 2 or 3 sections, has to be harder to quantify.  I have found nothing on this subject

 

Thanks,

 

Andy

[Stuart_G]

1 hour ago, ajlacombe said:

I am an overthinking engineer and have recently gone through some fittings and a lot of shaft experimentation.  I want to find some discussion about the profile stiffnesses and feel.

 

For Butt, Mid and Tip sections - I want to know when stiffness in a section goes up or down, what does it do to feel.  Also combos of stiffness changes in multiple sections.  I am sure it is easier to say if stiffness goes up or down in one section - this will happen.  But then when you change 2 or 3 sections, has to be harder to quantify.  I have found nothing on this subject

 

Thanks,

 

Andy

 

 

That's because there is no one single answer nor is it well understood.  The subjective nature of the interpretation of feel makes it almost impossible to get any useful or consistent correlations.    So it largely depends on the mechanics and the (very subjective) sensitivity of the person swinging it - and interestingly enough, when during the swing they are sensitive to it.

 

Now as a VERY rough generalization, thanks to the countless hours Tom Wishon has put into refining the concept of shaft fitting (and one of the first to try and establish a detailed database of stiffness profiles), it's been observed that:

 

1) Butt/Mid stiffness tends to influence the feel of the shaft loading in transition more than other parts of the swing.

 

2) Most people can't really tell the difference between a stiffness change in the butt vs the mid-section (including most of those people that think they can).

 

3) Tip stiffness tends to have a bigger influence on feel during the release and unloading of the shaft.

 

4) there are no universal standards among the different OEM's for evaluating the stiffness of the different parts or the shaft as a whole - so descriptors from the OEM's don't always translate equally to other OEM's.    Accurate comparisons across different OEM's requires independent testing and maintenance of the resulting DB.  And no one is going to do that for free.

 

Bottom line, is that for now at least (and for the foreseeable future),  trial and error is the only reliable way to find the best fit for the shaft stiffness profile.  There are no short cuts.

Edited June 24, 2021 by Stuart_G

[ajlacombe]

9 hours ago, Stuart_G said:

 

 

That's because there is no one single answer nor is it well understood.  The subjective nature of the interpretation of feel makes it almost impossible to get any useful or consistent correlations.    So it largely depends on the mechanics and the (very subjective) sensitivity of the person swinging it - and interestingly enough, when during the swing they are sensitive to it.

 

Now as a VERY rough generalization, thanks to the countless hours Tom Wishon has put into refining the concept of shaft fitting (and one of the first to try and establish a detailed database of stiffness profiles), it's been observed that:

 

1) Butt/Mid stiffness tends to influence the feel of the shaft loading in transition more than other parts of the swing.

 

2) Most people can't really tell the difference between a stiffness change in the butt vs the mid-section (including most of those people that think they can).

 

3) Tip stiffness tends to have a bigger influence on feel during the release and unloading of the shaft.

 

4) there are no universal standards among the different OEM's for evaluating the stiffness of the different parts or the shaft as a whole - so descriptors from the OEM's don't always translate equally to other OEM's.    Accurate comparisons across different OEM's requires independent testing and maintenance of the resulting DB.  And no one is going to do that for free.

 

Bottom line, is that for now at least (and for the foreseeable future),  trial and error is the only reliable way to find the best fit for the shaft stiffness profile.  There are no short cuts.

Damn - I did looking at Tom's stuff and have been a follower of his for many years - I think he was the first with the larger right hand grip among many other pioneering things.

 

All of what you said makes sense especially the last paragraph - that is a bummer, because after having a fitting this week and being able to really feel the difference between shafts, but was not really bale to say why I felt what I felt. It is fun being given a shaft and not paying attention to what it is you are swinging, then describe what you are feeling and seeing how well you can center it on shots

 

I knew it was a long shot when companies describe the profile with terms like Firm, Firm+ Stiff and Medium 🙂 It would be cool to go through that exercise of test and describe to get a baseline, but that would take a place with tons of shafts and a lot of time.

 

Thanks again!

[ShowMe]

I'd be interested to see any studies on the correlation of feel to performance.  Do the best feeling shafts for an individual golfer produce the best performance results for that same individual golfer?

 

Based on my personal experience, I suspect there is not a material correlation (R-squared greater than 90%) between the two, generally speaking.  For me, the best feeling shaft is not usually the one that produces the best results.  Others may have the opposite experience, though.  Hence, my suspicion that there is not a high level of statistical correlation.

 

MGS did a good study a few years ago that touched on this a little.  The guy who ran the study is a PhD and works for Ping.  In the end they concluded,

 

""After evaluating the data produced by the motion-capture system, it was clear the shafts where (sic) loading and unloading in a different fashion. The difference in actual dynamic deflection of the shaft during the downswing influences the sensation the player experiences, and can lead to kinetic responses that vary in consistency, timing, and magnitude. Ultimately what I am saying is that players tend to “get along with” different dynamic bending profiles, leading to more-consistent performance and sometimes more-efficient delivery of the club head, a behavior that was also evident in the previous fitting example. This is a great instance of how different shafts can lead to significantly different results, even when the two shafts look similar and have similar flex codes."

 

I think the "get along with different dynamic bending profiles" statement is the key.  For me, the EI profile I get along with doesn't feel as good as some other EI profiles, but it produces better results.

[Stuart_G]

39 minutes ago, ShowMe said:

I'd be interested to see any studies on the correlation of feel to performance.  Do the best feeling shafts for an individual golfer produce the best performance results for that same individual golfer?

 

I would as well but doubt how useful they really would be.  One of the problems is that most of those higher education studies tend to limit the testing to the better golfers.  Usually in the pretext of them having more consistent swings and results and therefore more likely for variations in the data to be attributed to the factor that's being tested.   That's true but the down side is that the better players also tend to be better able to adjust their swing and adapt to equipment differences.

 

What does it even mean for a shaft to feel "good" in the context of the swing?  Personally I think it's more just a case of familiarity and expectations than of any real sense of aesthetics.  But there certainly could be more to it than that.

 

The second problem many of these studies have is they don't even look at the context of how good (or bad) a fit the rest of the test club specs might be for the person being tested.

 

Quote

Based on my personal experience, I suspect there is not a material correlation (R-squared greater than 90%) between the two, generally speaking.  For me, the best feeling shaft is not usually the one that produces the best results.  Others may have the opposite experience, though.  Hence, my suspicion that there is not a high level of statistical correlation.

 

It can depend on how you define "best results".  That's not really the right approach in the context of a study like this.  The study should really focus on how the shaft might influence the swing and results - but without the judgment on whether it's a good influence or bad.   That's because, depending on what flaws or general tendencies might exist in the individuals swing, the exact same "influence" could help and generate better results in one person, yet do the complete opposite for a different individual.     The one judgement that might be made that's really independent of what the players "natural baseline" might be is the consistency of the results.   But even improvements in that can can be accompanied by other negative factors (e.g. more consistent results but slower swing speeds).

 

Regardless, I don't think you'd find any significant single statistical result.   It seems to act more like a spectrum disorder.   There are clearly some people that can swing a very wide range of shafts with various stiffnesses and have little to no significant effect on the swing and the results.    There are also those who have to get a very specific feel of the shaft loading/unloading or else their swing completely falls apart.  Then there are the majority of us who are someplace between those two ends of the spectrum.

 

 

Edited June 25, 2021 by Stuart_G