Does a lighter shaft make the club head feel heavier?

[Stuart_G]

Plot and compare the first and second moments, not the swing weight.

Edited June 16, 2021 by Stuart_G

[joostin]

On 6/15/2021 at 8:13 PM, BREWMASTER95060 said:

 

BLUE= LEAD TAPE ON SHAFT @  14" 

ORANGE=TOTAL CLUB WEIGHT
MAROON SWING WEIGHT FROM = http://www.leaderboard.com/SWINGWEIGHT
RED IS THE CLUB BALANCE OF THE CLUB IS GC= ((G1*D1)+(G2*D2)+(G3*D3).../GRAMS
QUESTION DO YOU FEEL THE CHANGE IN TOTAL WEIGHT OR DO YOU FEEL THE CHANGE IN BALANCE POINT?
I FEEL THE CHANGE IN BALANCE POINT.

 

Brew, taking your data to do a little analysis - not just for you but anyone reading this.  What we do feel is weight, torque (moment), like with a torque wrench, and MOI... however not only just one MOI nor torque at one rotational axis in the swing.  Our hands of course aren't exactly at the butt (red rotational arrow below), but regardless here's how the numbers work out if we converted to the more known torque unit of lb-ft at the butt:

 

That said..... feel and swings are very personal, and I have lead tape on heads and shafts myself.  I just want to point out that swingweight scales, MOI scales, even all our calcs, can never truly represent with singular SW/torque/MOI numbers the changing axes and motions of our swings when it comes to feel.  You can take torque at the butt, at the SW scale's 14", or anywhere you like, and same with MOI.

 

So my personal take, as much as I'm a numbers guy like you, is to adjust by feel and performance, not necessarily trying to hit perfect numbers on the scales/calcs.  🍺

[BREWMASTER95060]

On 6/16/2021 at 2:04 AM, Stuart_G said:

Plot and compare the first and second moments, not the swing weight.

same SW but they feel different.
moments..... well heaver club more MOI. 

[Righty to Lefty]

Depends on how the weight was distributed along the shaft in relation to the replacement as the previous or new shaft may be more tip heavy or light in comparison.  If the swing weight decreases then the club head feel will decrease, if it increases then club head feel will increase. 

[Stuart_G]

4 hours ago, BREWMASTER95060 said:

same SW but they feel different.
moments..... well heaver club more MOI.

Same swing weight is meaningless.  You don't hold the club at the 14" fulcrum point the swing weight scale uses.  That's why you need to look at the first moment about the grip instead - that's where you hold the club and what you're likely to feel in the first part of the backswing.

 

MOI is the second moment.

Edited June 18, 2021 by Stuart_G

[BREWMASTER95060]

12 hours ago, Stuart_G said:

Same swing weight is meaningless.  You don't hold the club at the 14" fulcrum point the swing weight scale uses.  That's why you need to look at the first moment about the grip instead - that's where you hold the club and what you're likely to feel in the first part of the backswing.

 

MOI is the second moment.

I think we are talking about 2 different things.
and yes the club I added 25 grams @14"
will have A higher MOI.

[Buzzkill]

Does a lighter shaft make the club head feel heavier?
 

Only if it’s swing weighted higher.

[BREWMASTER95060]

36 minutes ago, Buzzkill said:

Does a lighter shaft make the club head feel heavier?
 

Only if it’s swing weighted higher.

lighter shaft lower balance point

[Buzzkill]

11 minutes ago, BREWMASTER95060 said:

lighter shaft lower balance point

I’ve always had to add a bunch of tip weights to Steelfiber shafts so I say no to lighter shafts making heads feel heavier!

[Stuart_G]

10 hours ago, BREWMASTER95060 said:

I think we are talking about 2 different things.
and yes the club I added 25 grams @14"
will have A higher MOI.

 

It's possible.

 

I've been talking (or answering questions) about the weight feel of a club and what measurements are useful for that (first and second moments) and what are not (swing weight and balance point).

 

You seemed to be trying to convince others that you can feel the difference in balance point.   If you've been talking about something different, you need to take a bit more time when writing to supply the necessary details to make your meaning more clear.

 

Edited June 19, 2021 by Stuart_G

[Valtiel]

13 minutes ago, Stuart_G said:

 

It's possible.

 

I've been talking (or answering questions) about the weight feel of a club and what measurements are useful for that (first and second moments) and what are not (swing weight and balance point).

 

You seemed to be trying to convince others that you can feel the difference in balance point.   If you've been talking about something different, you need to take a bit more time when writing to supply the necessary details to make your meaning more clear.

 

[joostin]

@Stuart_G and @BREWMASTER95060 Here's my attempt at mediating...

 

Brew, we cannot feel a balance point alone, we can only feel the moments associated with it (first, force x distance of balance point from the hands), like SG said.  Torque and Moment are interchangeable for our purposes and I like to say torque because that's what people understand - like torque wrench, torque of car engine, ... "First moment of mass" is basically torque (though torque is measured in force x distance, not mass x distance, and force here is just mass times gravity).  "Second moment of mass" is MOI of the club.  An Auditor takes MOI from a fulcrum at the butt, so I'm also taking torque from the same butt fulcrum.  These are things we can feel, and to clarify what I posted above, here are my notes on Brew's calcs again with labels:

 

[gram*inch incorrectly called torque in my pic, but my conversion to lb-ft is correct for torque]

 

When holding a club in the air, the hands basically create a moment, or coupling of forces - one pulls up, one pushes down.  Even one hand does that - index finger side gives a force up, pinky side gives a force down.  So that is what's providing the torque, and it's not centered at the butt.  It balances the moment created by the club weight times distance to the balance point.

 

Btw in case anyone cares, the terms weight and mass get all muddled because "weight" scales show mass (grams, lbm), but they really measure a force (Newtons, lbf) and convert to mass based on calibration to earth's gravity.  Take the scale to the moon and the scale is wrong for the gram or pound mass it would read (a 470g club would still be 470g in mass, but would weigh less).  Weight really is a force, mass x gravity.  And to make matters more confusing, 1 lb mass exerts 1 lb force, 1 slug mass exerts 32.2 lb force, while 1 kg mass exerts 9.8 N of force on earth. 🤯

 

Also the first and second moment terms get confusing (just try to look it up online and you'll know what I mean).  MOI for a club in rotation is "second moment of mass".  Don't confuse with "First moment of area" (in units like in³) and "second moment of area" (in⁴) as they do not deal with mass, just cross-sectional area of an object, and are used for structural and beam calculations, not golf club MOI.  "First or second moments of inertia" are not really a thing.  "First" and "second" refer to the power of the distance, ie distance¹ and distance² (squared).  No one cares but I'm just trying to explain to whoever reads this far.  Yes, I had to look this up to brush up on the subject. 🙂

 

@Stuart_G I know you're the smartest guy on the block, but throwing terms like "first moment" and "second moment" probably get golfers' brains into: 🤯🙄😵??? .... As if my explanatory post didn't too LOL.  Here's to "know your audience"-- torque and MOI.

 

Btw, sorry OP for spilling the can of worms.

[Stuart_G]

42 minutes ago, joostin said:

 

@Stuart_G I know you're the smartest guy on the block, but throwing terms like "first moment" and "second moment" probably get golfers' brains into: 🤯🙄😵??? .... As if my explanatory post didn't too LOL.  Here's to "know your audience"-- torque and MOI.

 

That's why I explicitly explained what the first moment was in the first post I mentioned it.

 

I personally don't like "torque" because it's dependent on the force applied to the c.g.  In golf, that may be gravity during the backswing but it's the centrifugal force of the club releasing in the down swing that contributes to the feel.  Two different forces so two different torques but the same first moment contributing to the feel.  Actually it's more than two since the actual torque created by the moment is dependent on the orientation of the club relative to the direction of the force.  So actual torque felt at the hands is not constant during the swing.

 

 

 

 

[BREWMASTER95060]

283/468=0.6047 head feels heaver
283/493=0.5740 head feels lighter but MOI higher
This is what I feel.
Above .60 feels like I am swinging a BRICK
on the end of a string.

Edited June 20, 2021 by BREWMASTER95060

[joostin]

21 hours ago, Stuart_G said:

 

That's why I explicitly explained what the first moment was in the first post I mentioned it.

 

I personally don't like "torque" because it's dependent on the force applied to the c.g.  In golf, that may be gravity during the backswing but it's the centrifugal force of the club releasing in the down swing that contributes to the feel.  Two different forces so two different torques but the same first moment contributing to the feel.  Actually it's more than two since the actual torque created by the moment is dependent on the orientation of the club relative to the direction of the force.  So actual torque felt at the hands is not constant during the swing.

 

 

 

 

I think torque as we have it in the thread so far can apply at the backswing then at the top transition.  The rest of the swing including the centripetal / centrifugal force at release is different like you said (that would add a pulling feel), but yeah it's very complicated, and dependent on someone's swing - "handsy"-ness, feel and all, which was my point previously:

 

On 6/17/2021 at 1:31 AM, joostin said:

  I just want to point out that swingweight scales, MOI scales, even all our calcs, can never truly represent with singular SW/torque/MOI numbers the changing axes and motions of our swings when it comes to feel. 

 

12 hours ago, BREWMASTER95060 said:

283/468=0.6047 head feels heaver
283/493=0.5740 head feels lighter but MOI higher
This is what I feel.
Above .60 feels like I am swinging a BRICK
on the end of a string.

I get it, and can't explain it by these calculations alone when weight, torque and MOI (from butt) will be higher with swingweight the same.  Adding that perception of head movement due to shaft flexibility (maybe relative to shaft inertia) can be at play too.  MBI people I'm sure would have something to say.  In the end, your feel and performance, and how your body responds to the club, is much more important.  That much can't be disputed! 

Edited June 20, 2021 by joostin

[Fairway14]

If the OP wants to utilize a lighter weight shaft, and also increase his sense of the club's head weight, then use of a super light grip is a good solution.

[Stuart_G]

13 hours ago, BREWMASTER95060 said:

283/468=0.6047 head feels heaver
283/493=0.5740 head feels lighter but MOI higher
This is what I feel.
Above .60 feels like I am swinging a BRICK
on the end of a string.

 

Sorry, those images and numbers don't tell me anything.   Poor labeling and the equations are hidden so can't be checked for accuracy or assumptions.  

[BREWMASTER95060]

5 hours ago, joostin said:

  Adding that perception of head movement due to shaft flexibility (maybe relative to shaft inertia) can be at play too.

yes

 

Edited June 20, 2021 by BREWMASTER95060

[BREWMASTER95060]

3 hours ago, Stuart_G said:

 

Sorry, those images and numbers don't tell me anything.   Poor labeling and the equations are hidden so can't be checked for accuracy or assumptions.  

head weight/club weight=a feel thing

283/468=0.6047 head feels heaver
283/493=0.5740 head feels lighter but MOI higher
This is what I feel.
Above .60 feels like I am swinging a BRICK
on the end of a string.

real world example:

 

Edited June 20, 2021 by BREWMASTER95060

[Noodler]

10 hours ago, BREWMASTER95060 said:

head weight/club weight=a feel thing

283/468=0.6047 head feels heaver
283/493=0.5740 head feels lighter but MOI higher
This is what I feel.
Above .60 feels like I am swinging a BRICK
on the end of a string.

real world example:

 

 

I guess this once again shows that golfers are unique in their preference for "feels".  Any build under 60% (you show ".60") and I can't track the head position at all.  My target builds are generally around 65% of the club weight being in the head.  I like my MOI to be around 2675, the MBI at about 63-65, and the total weight of my 7 iron at ~435g.  Using AMT shafts with their 3g weight increment is almost perfect for getting a consistent MBI value across the entire set.

[BREWMASTER95060]

"unique in their preference for "feels""
:)

[BREWMASTER95060]

On 6/20/2021 at 10:05 PM, Noodler said:

Using AMT shafts with their 3g weight increment is almost perfect

I use on avg. 5 grams per shaft.
The 2 formulas I used for the set below 
for matching:
Balance point club 2=(((balance point club 1)^2 * weight club 1)/ total weight club 2)^(1/2)
An approximation for moment of inertia did not own an auditor when I built these: 
MOI= head weight* (butt to club head sweet spot)^2+(1/3)*(shaft weight)*(shaft length^2)+(1/3)*(grip weight)*(grip length^2)

Edited June 22, 2021 by BREWMASTER95060

[Inferno2ss]

I just had an iron fitting and for me the lighter the shaft the heavier the "clubhead" felt.  My old clubs had a lighter shaft and I always felt like I was fighting the clubhead on my backswing. 

The minute he put me in a heavier shaft everything felt more balanced and the clubhead felt lighter because of it.

[BREWMASTER95060]

I purchased Hogan hybrid H2

Off eBay took it out of the box I knew something was wrong I can feel it turns out I had a 90 gram butt weight.