Why do putters have high impact ratios? Wouldn't low be better?

[BaffledGoat]

I've been struggling with this question, and substantial google searching hasn't turned up an answer, so I am hoping to turn to the minds on here...

 

Putters have a higher impact ratio (aka smash factor) than is allowable on any other club (>1.5). I assume this is an intentional choice among putter manufacturers, i.e. if they wanted to create a putter with an impact ratio of, say, 1.1, they could do that by using a softer face.

 

My view: A higher impact ratio causes a loss of control because small changes in the size of the backstroke lead to disproportionately larger changes in ball speed. With a lower impact ratio, golfers could more finely tune their putts, as the range of motion required for different speeds would be broader, allowing for more nuanced control.

 

An example: Based on my testing with a Capto and GC Quad, the ratio of [backstroke length in inches]/[ball speed in mph] for my stroke/putter is 2.0, i.e. a backstroke of 8 inches results in a putt traveling at 4 mph¹. That means that if I am trying to hit a putt that needs to travel at 4mph, but I accidentally make a stroke that is 7 inches back instead of 8 the ball will travel at 3.5 mph (~12% short).

Now imagine I had a putter with a lower impact ratio, for which the above ratio was instead 3.0. To hit a putt with 4 mph ballspeed, I need to make a 12 inch backstroke. Imagine I make the same 1 inch error and produce a backstroke that's 11 inches. That results in a ballspeed that's 3.67 mph (only ~8% short). 

 

It seems to me that low impact ratio putters would allow golfers to minimize the impact of stroke size errors. Given that, why do all putters have such high impact ratios? 

 

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¹ The values here are (obviously) highly contextual, i.e. specific to my stroke/putter/etc. But I believe the underlying logic applies to any putter/stroke.

Edited March 26 by BaffledGoat

[glofer]

Love the thought process and experimentation, BaffledGoat. Great to see data rather than conjecture.

 

I think you need to adjust (or at least test) one assumption in your experiment. 

 

"Imagine I make the same 1 inch error"

 

Assigning the error value as a % rather than the same raw value is likely more realistic, and may equalize (at least) high impact ratio putter performance, by reducing the overall length of the backswing, not to mention the lateral errors which certainly increase with longer swings.

 

Would be interested if you test for a similar % error, and also for lateral (offline) dispersion. 

 

[Socrates]

You can vary the impact just by changing the ball you are using (softer vs harder cover).  FWIW, I have found that using a softer ball (my Ping has a dual durometer face) causes me to lose speed control on longish putts.  So I prefer a ball that is slightly firmer.  For example the TM Soft Response is too soft to putt with and prefer Tour Response or the AVX (or similar) because I get more consistent results putting. 

 

In a nutshell, I don't all of sudden get a "spring" off the face and the ball going too far for the swing I put on it.  The OEM's spend a long time creating materials for putter faces and I think they know what they are doing.  Of course, they can't predict what ball you might use or how you put a stroke on the ball.

[tatertot]

Maybe a case of paralysis by analysis?

[MattM97]

You're thinking like 0.05% of golfers would when it comes to putting, it's like Bryson level but he will calibrate his stroke to the green speed each day where amateurs don't. Also like @tatertot said it's paralysis by analysis, what if your stroke is 9" instead of 8" now? Also that back stroke of 8" to travel the ball at 4mph what speed green is that on? Cause that stroke and speed would only apply to a small window of stimps I assume.

 

As for the soft face, well they're not very liked, there are plenty of options for a soft face and they're not too popular but they're available. 

[Long_Left]

2 hours ago, BaffledGoat said:

I've been struggling with this question, and substantial google searching hasn't turned up an answer, so I am hoping to turn to the minds on here...

 

Putters have a higher impact ratio (aka smash factor) than is allowable on any other club (>1.5). I assume this is an intentional choice among putter manufacturers, i.e. if they wanted to create a putter with an impact ratio of, say, 1.1, they could do that by using a softer face.

 

My view: A higher impact ratio causes a loss of control because small changes in the size of the backstroke lead to disproportionately larger changes in ball speed. With a lower impact ratio, golfers could more finely tune their putts, as the range of motion required for different speeds would be broader, allowing for more nuanced control.

 

An example: Based on my testing with a Capto and GC Quad, the ratio of [backstroke length in inches]/[ball speed in mph] for my stroke/putter is 2.0, i.e. a backstroke of 8 inches results in a putt traveling at 4 mph¹. That means that if I am trying to hit a putt that needs to travel at 4mph, but I accidentally make a stroke that is 7 inches back instead of 8 the ball will travel at 3.5 mph (~12% short).

Now imagine I had a putter with a lower impact ratio, for which the above ratio was instead 3.0. To hit a putt with 4 mph ballspeed, I need to make a 12 inch backstroke. Imagine I make the same 1 inch error and produce a backstroke that's 11 inches. That results in a ballspeed that's 3.67 mph (only ~8% short). 

 

It seems to me that low impact ratio putters would allow golfers to minimize the impact of stroke size errors. Given that, why do all putters have such high impact ratios? 

 

--

¹ The values here are (obviously) highly contextual, i.e. specific to my stroke/putter/etc. But I believe the underlying logic applies to any putter/stroke.

 

This sums up in words why I've always preferred a softer face "dead" putter feel. My body/brain prefers bigger movements when putting.

[Mike412]

Looking at it from another direction….. It the ratio was closer to 1 it means you would a longer/harder stroke for all putts. I would imagine that would cause far more issues than the multiple transfer of energy. If I had to hit a 3 footer harder than I do now I’d imagine I would miss a lot more of them.

 

Thinking about it further, it would be interesting to see if longer putting would improve with a higher ratio. Seems that if you could shorten the stroke it would probably help once you got a feel for distance control.

 

All things considered, I think it at a pretty good middle ground.

[dmecca2]

You need to look at % error. Accidentally making a 1 inch longer or shorter stroke on a 8 inch long stroke is more difficult to do than on a 12 inch long stroke. So in that sense, the higher impact ratio putter is easier to make a consistent stroke with because your stroke is shorter for the same length putt.

[BaffledGoat]

I really appreciate the thoughts here! I’ve been pondering this for a while and you guys brought up some things I hadn’t considered. Responding specifically to a few points:

 

Quote

Assigning the error value as a % rather than the same raw value is likely more realistic

 

I think you’re 100% right that using only absolute error is not the right way to think about this. My intuition is that using *only* percentage errors is also isn’t right; rather, in reality the right framework is a combination of absolute & percentage error.

 

We see this dynamic (“error is a combination of absolute and percent”) in the strokes gained data. For example, looking at PGA tour median leave for 0-100 yd shots,  the % median leave decreases as shots get longer, but the absolute median leave # increases.

 

I’ve also seen this dynamic in my own putting data, but I won’t share it here as I imagine Mark Broadie’s aggregate PGA tour findings are far more compelling than a random hacker’s n=1 🙂

 

If you buy the above (lmk if you don’t :)), then it would still be true that lower putter impact ratios would be desirable.

 

Quote

ould be interested if you test for a similar % error, and also for lateral (offline) dispersion. 

 

With modern, high MOI putters, you need a large lateral impact error in order to have an appreciable affect on ball speed. I think an increase in club head speed precision pretty handily outweighs the impact of increased lateral impact error. I’ve done the math on this and would be happy to share, but better than anything I could do is Sasho MacKenzie’s analysis.

 

Quote

You're thinking like 0.05% of golfers would when it comes to putting, it's like Bryson level but he will calibrate his stroke to the green speed each day where amateurs don't. Also like @tatertot said it's paralysis by analysis, what if your stroke is 9" instead of 8" now?

 

I realize that few are as psychopathic/pedantic as me to spend a lot of time with the actual math on this. But I’d argue that even for the 99.999% of golfers who have no idea how many inches their putting stroke is, the underlying logic would still be beneficial to them—if they’re able to use a broader the range of motion required to control putt speed, they’ll be more successful.

 

Quote

As for the soft face, well they're not very liked, there are plenty of options for a soft face and they're not too popular but they're available. 

 

Interesting! I didn’t know this. What models are known to have a soft face?

[MattM97]

3 minutes ago, BaffledGoat said:

I realize that few are as psychopathic/pedantic as me to spend a lot of time with the actual math on this. But I’d argue that even for the 99.999% of golfers who have no idea how many inches their putting stroke is, the underlying logic would still be beneficial to them—if they’re able to use a broader the range of motion required to control putt speed, they’ll be more successful.

 

 

Interesting! I didn’t know this. What models are known to have a soft face?

 

The thing is your idea involves the need to practice, most guys again don't practice, they usually don't adjust their stroke for distance, it's the same stroke just over accelerated and jerky to a stabby kinda stroke. The ones who practice are using all kinds of inserts or materials and they should be dialing in their putter. 

 

As for soft putters there are a ton, but also what's super soft for me could be still hard for you but some options: 

 

- Kevin Burns Pyramid Grooves - can be found cheap on ebay if you're right handed.

- Bobby Grace HSM Insert - Can be found cheap on ebay

- Bettinardi F.I.T. Face or RC Face - F.I.T. is softer. 

- Evnroll, some say it's tingy it really depends on the model. 

- Odyssey DFX - their softest insert. 

- TaylorMade Nubbins - Old putter basically a basketball cover as the insert. 

 

[BaffledGoat]

Great/helpful list, thanks @MattM97! 🙏🏻

[Sean124]

I have no thoughts on the topic, but maybe try an Evnroll putter. I’ve seen several people say they are slower off the center of the face than most. 

[glofer]

 

"in reality the right framework is a combination of absolute & percentage error."

"If you buy the above (lmk if you don’t :)), then it would still be true that lower putter impact ratios would be desirable."

 

I definitely agree - I threw out % as a thought-provoker, but agree it's probably most accurately a declining % as distance increases.

 

In terms of lateral - I wasn't speaking to lateral impact error and its effect on distance, but rather, that the increased clubhead speed required by a lower impact putter would introduce more offline (left-right error) and may mitigate or even negate (if your theory is correct) distance benefits of a low impact putter. 

 

Kudos - I can tell you're not thrown off by the responses of those who don't understand your thesis - you're not advocating for a putt-by-backswing-length prescription, but rather you're using backswing length to illustrate the effect of impact ratio, and exploring this academically, so there is no paralysis involved whatsoever, no increased practice required, any more than wondering about driver smash factor and its impact on driver consistency.  Similarly, the concepts of feel / face softness/ball firmness, and the idea of switching balls, are mostly to completely irrelevant to your topic.  

 

Mike412's thoughts are in line with mine, as evidenced by my % (or declining %) theory.  And dmecca2 sums up what I think would be the outcome, but if you do more testing, please share.