How does a carbon faced driver get hotter with use?

[03trdblack]

With all the conversations around Rory and Scotty having to switch drivers at the PGA, it led me to realize that I don't understand it. 

 

Can someone that understands carbon fiber properties extremely well explain the physics behind how a carbon face driver can get hotter with repeated strikes over time?  I understand how metal would become thinner and more flexible over time with repeated impacts to the same area but carbon fiber doesn't work that way. It doesn't get thinner and doesn't become more flexible, in fact, I would think that the layers would start to delaminate and it would actually lose speed over repeated impacts and eventually just splinter or go dead. 

 

Our golf shafts are made with essentially carbon fiber but they don't get more flexible or stiffer over time with repeated swings so how would a driver face?

 

Anyone else have any insight into this?

[Socrates]

Any material will wear away with repeated strikes.  Doesn't matter if it is carbon fiber, titanium, wood or granite.  Any time a material gets worn away (thinner), it will become more flexible.  Also, the body that supports the clubface will also fatigue over time and use and will become more flexible.  Would that show up in a  CT test or just a COR test, I don't know.

 

Carbon fibre isn't some magical material that is impervious to wear.

[saebaebae]

59 minutes ago, 03trdblack said:

With all the conversations around Rory and Scotty having to switch drivers at the PGA, it led me to realize that I don't understand it. 

 

Can someone that understands carbon fiber properties extremely well explain the physics behind how a carbon face driver can get hotter with repeated strikes over time?  I understand how metal would become thinner and more flexible over time with repeated impacts to the same area but carbon fiber doesn't work that way. It doesn't get thinner and doesn't become more flexible, in fact, I would think that the layers would start to delaminate and it would actually lose speed over repeated impacts and eventually just splinter or go dead. 

 

Our golf shafts are made with essentially carbon fiber but they don't get more flexible or stiffer over time with repeated swings so how would a driver face?

 

Anyone else have any insight into this?

Metal is firm and is going to retain its shape. Once the ball strikes, it will trampoline and return back.
 

Carbon fiber is similar but with repetitive use, the trampoline effect becomes pronounced overtime.  This is because the fiber breaks down and becomes more flexible while retaining the shape. As the ball strikes the area it will push the limit more and more.
 

I used to work for a baseball manufacturer, where there were metal and composite bats.

[Stuart_G]

7 hours ago, 03trdblack said:

I understand how metal would become thinner and more flexible over time with repeated impacts to the same area but carbon fiber doesn't work that way.

 

All solid materials work that way.  And it's not just about thickness - it's more about micro-fractures that form due to impact stresses (than it is about plastic deformation) that causes the material to get slightly weaker.

 

7 hours ago, 03trdblack said:

Our golf shafts are made with essentially carbon fiber but they don't get more flexible or stiffer over time with repeated swings so how would a driver face?

 

Micro fractures do occur in the shaft.   It's just that:

 

1) the faces get significantly higher stresses - there is no direct impact to the shaft the way there is to the face - the momentum of the head actually "softens" the stresses that occur in the shaft.

 

2)  the shafts are designed to be significantly more flexible to start with so the change is just not big enough to be noticeable to our sense of feel.

 

[cardoustie]

My question … is there a list of failed drivers at the PGA … were they all TMade ?//

[King_Slender]

My theory: 

 

Standard TM drivers are made with 60 layers of carbon fiber, per their website.

 

The drivers they give the pros have less layers and thus a thinner face. 

[Ger21]

Just now, King_Slender said:

My theory: 

 

Standard TM drivers are made with 60 layers of carbon fiber, per their website.

 

The drivers they give the pros have less layers and thus a thinner face. 

 

Very unlikely, imo. Off the shelf drivers are already at the very limit of the rules.  Anything thinner would likely be illegal to start with.

[03trdblack]

Just now, King_Slender said:

My theory: 

 

Standard TM drivers are made with 60 layers of carbon fiber, per their website.

 

The drivers they give the pros have less layers and thus a thinner face. 

 

I'd argue the complete opposite of this. Pros don't want their driver faces to fail and if anything I feel the companies would give them even stronger faces with more attention paid to the bond between the face and the body so that the face doesn't pop out like the retail clubs. 

[Llortamaisey]

1 hour ago, Stuart_G said:

 

1) the faces get significantly higher stresses - there is no direct impact to the shaft the way there is to the face

 

You must play with a lot better golfers than I do. 

[iNeedMoreGolf]

The ball bites the face on every impact. Everyone knows this. Carbon face feels softer then steel face so its easier for ball to bite. Each bite makes face thinner and adds 15 yards duh. Problem solved.

[Valtiel]

1 hour ago, King_Slender said:

My theory: 

 

Standard TM drivers are made with 60 layers of carbon fiber, per their website.

 

The drivers they give the pros have less layers and thus a thinner face. 

 

1 hour ago, Ger21 said:

 

Very unlikely, imo. Off the shelf drivers are already at the very limit of the rules.  Anything thinner would likely be illegal to start with.

 

1 hour ago, 03trdblack said:

 

I'd argue the complete opposite of this. Pros don't want their driver faces to fail and if anything I feel the companies would give them even stronger faces with more attention paid to the bond between the face and the body so that the face doesn't pop out like the retail clubs. 

Callaway has even said as much…that pros get drivers with *thicker* faces because both durability and USGA conformity are far more important than the tiny differences in speed between a comfortably legal driver and a barely legal driver. 

[Jc0]

2 hours ago, cardoustie said:

My question … is there a list of failed drivers at the PGA … were they all TMade ?//

 

Are you on a which hunt? All brands fail. The same thing happen to Xander at the British open like a year or two ago. 

 

All driver's get hotter over time until they fail. Carbon fiber has a bit more flexibility so the odds of it failing the test are probably higher because it's less prime to cracking. Where a metal faced driver would have already cracked a carbon fiber driver will continue to work. 

 

Also these are failing by like .001. It's not like they are getting 5-10 yards extra distance out of them. 

[Shallowface]

30 minutes ago, Valtiel said:

 

 

Callaway has even said as much…that pros get drivers with *thicker* faces because both durability and USGA conformity are far more important than the tiny differences in speed between a comfortably legal driver and a barely legal driver. 

 

1 hour ago, 03trdblack said:

 

I'd argue the complete opposite of this. Pros don't want their driver faces to fail and if anything I feel the companies would give them even stronger faces with more attention paid to the bond between the face and the body so that the face doesn't pop out like the retail clubs. 

If a pro's clubhead fails, they just go to the trailer and get another one.  Or send someone to the locker for the backup.

 

Not like us where we have to call customer service and then wait for the brown truck.

 

Remember that it was the PGA of America engaging the USGA for this testing.  Does this happen on the PGA Tour?

 

Not that I know of.

 

And it doesn't have to.  The USGA and its governance has no authority over the PGA Tour except that which the Tour grants it.  If the PGA Tour decided tomorrow that they wanted to make their own rules, they would have every right to do so.  And the golf world would go right along with it because the PGA Tour is relevant and the USGA isn't anymore except for the tiny handful of events it runs. 

 

All that said, the difference between a driver that's barely legal and one that's barely illegal would be negligible.

 

BTW, would it violate the 14 club rule to carry a backup driver head in one of the pockets of the bag?

Edited May 24 by Shallowface

[Hawkeye77]

Who says they failed because they were "hotter"? 

[Cameron Circle T]

25 minutes ago, Shallowface said:

 

If a pro's clubhead fails, they just go to the trailer and get another one.  Or send someone to the locker for the backup.

 

Not like us where we have to call customer service and then wait for the brown truck.

 

Remember that it was the PGA of America engaging the USGA for this testing.  Does this happen on the PGA Tour?

 

Not that I know of.

 

And it doesn't have to.  The USGA and its governance has no authority over the PGA Tour except that which the Tour grants it.  If the PGA Tour decided tomorrow that they wanted to make their own rules, they would have every right to do so.  And the golf world would go right along with it because the PGA Tour is relevant and the USGA isn't anymore except for the tiny handful of events it runs. 

 

All that said, the difference between a driver that's barely legal and one that's barely illegal would be negligible.

 

BTW, would it violate the 14 club rule to carry a backup driver head in one of the pockets of the bag?

 

Johnny Wunder and others have said they tend not to take them right to the limit because these guys don't like switching clubs.  Sure, it's more convenient to just have *a* driver when one fails on the tour.  But they get used to the exact one they're playing.  Take a look at Niblick-99 on ebay.  They sell a lot of the old tour department heads from Taylormade (one to three models out of date).  They're quite frequently not right up at the limit (they provide all the specs on the head and the CT's are regularly decently below the USGA limit).

 

Yes, the USGA regularly tests drivers at Tour events.  The USGA conducts the testing because they have the equipment to do it.  The on-site testing at Tour stops started five years ago: https://www.pgatour.com/article/news/latest/2019/09/06/new-driver-testing-program-pga-tour-builds-upon-previous-initiatives.  Before that, the heads would have to be shipped to the USGA for testing in NJ.

Edited May 24 by Cameron Circle T

[Socrates]

2 hours ago, cardoustie said:

My question … is there a list of failed drivers at the PGA … were they all TMade ?//

All clubs will fail - eventually.  Doesn't matter whose they are.  And no, you won't get a list as the details of the testing are not supposed to be released.  In this case, someone with an agenda released this information illegally. 

[Socrates]

2 hours ago, King_Slender said:

My theory: 

 

Standard TM drivers are made with 60 layers of carbon fiber, per their website.

 

The drivers they give the pros have less layers and thus a thinner face. 

Completely false.  Just because you have a theory, doesn't mean it is close to right. 

 

The pros actually get heads that are below the threshold of conformity.  They don't want anything to fail and heads are hand picked to make sure they are well below the CT levels.  The heads are not made any differently than a production head other than they are tested to make sure of their COR and CT numbers.  They check other parameter, but those are the key ones.  Every Tour player knows that eventually their head will crack or break or become illegal due to the high number of balls they hit and speed at which they generate.

[Socrates]

34 minutes ago, Shallowface said:

 

If a pro's clubhead fails, they just go to the trailer and get another one.  Or send someone to the locker for the backup.

 

Not like us where we have to call customer service and then wait for the brown truck.

 

Remember that it was the PGA of America engaging the USGA for this testing.  Does this happen on the PGA Tour?

 

Not that I know of.

 

And it doesn't have to.  The USGA and its governance has no authority over the PGA Tour except that which the Tour grants it.  If the PGA Tour decided tomorrow that they wanted to make their own rules, they would have every right to do so.  And the golf world would go right along with it because the PGA Tour is relevant and the USGA isn't anymore except for the tiny handful of events it runs. 

 

All that said, the difference between a driver that's barely legal and one that's barely illegal would be negligible.

 

BTW, would it violate the 14 club rule to carry a backup driver head in one of the pockets of the bag?

Then you would be mis-informed...

 

Routinely, drivers are tested during the year at PGA Tour events and some major championships in a randomized fashion to determine whether a driver is close to or over the limit. Maybe a third of the field might get called in on a particular week, and in addition at some tour events the USGA might test extra driver heads that are in the tour equipment vans to prevent any problems.

At the PGA Championship, the test was conducted at the request of the PGA of America, and the PGA controlled the dissemination of the results to players and the media. It is our understanding that drivers from many manufacturers were tested this week, and other players besides McIlroy might have failed the test, but we cannot confirm this information. The PGA of America declined to comment on the results this week, but did release the following statement:

“We can confirm that the USGA was invited to do club testing at the PGA Championship, at the PGA of America’s request. That testing program is consistent with the same level of support that the USGA provides to the PGA Tour and other championships, as part of their regular programs for driver testing. The standard process is for about a third of the field to be randomly tested under the program. 

 

[Shallowface]

1 minute ago, Socrates said:

Then you would be mis-informed...

 

Routinely, drivers are tested during the year at PGA Tour events and some major championships in a randomized fashion to determine whether a driver is close to or over the limit. Maybe a third of the field might get called in on a particular week, and in addition at some tour events the USGA might test extra driver heads that are in the tour equipment vans to prevent any problems.

At the PGA Championship, the test was conducted at the request of the PGA of America, and the PGA controlled the dissemination of the results to players and the media. It is our understanding that drivers from many manufacturers were tested this week, and other players besides McIlroy might have failed the test, but we cannot confirm this information. The PGA of America declined to comment on the results this week, but did release the following statement:

“We can confirm that the USGA was invited to do club testing at the PGA Championship, at the PGA of America’s request. That testing program is consistent with the same level of support that the USGA provides to the PGA Tour and other championships, as part of their regular programs for driver testing. The standard process is for about a third of the field to be randomly tested under the program. 

 

Well thanks for correcting me.  I know how much you enjoyed it.

[black bnr32]

46 minutes ago, Hawkeye77 said:

Who says they failed because they were "hotter"? 

PGA of America heavily implied it.

 

“Finding driver heads that have crept over the line of conformance is not an unusual occurrence, especially for clubs that are hit thousands of times over a long period of time,” Haigh said in a statement. “The results are kept confidential to protect players, who are unaware the club has fallen out of conformance and not responsible for it falling out of conformance other than hitting the club thousands of times.”

[Hawkeye77]

3 minutes ago, black bnr32 said:

PGA of America heavily implied it.

 

“Finding driver heads that have crept over the line of conformance is not an unusual occurrence, especially for clubs that are hit thousands of times over a long period of time,” Haigh said in a statement. “The results are kept confidential to protect players, who are unaware the club has fallen out of conformance and not responsible for it falling out of conformance other than hitting the club thousands of times.”

 

Falling "out of conformance" doesn't have to be "hotter" and that's not what that says - anyway, the OP was asking generally because of those two situations - more to nonconforming than "hotter".  Not seeing "heavily implied" at all.

[Socrates]

11 minutes ago, black bnr32 said:

PGA of America heavily implied it.

 

“Finding driver heads that have crept over the line of conformance is not an unusual occurrence, especially for clubs that are hit thousands of times over a long period of time,” Haigh said in a statement. “The results are kept confidential to protect players, who are unaware the club has fallen out of conformance and not responsible for it falling out of conformance other than hitting the club thousands of times.”

 

5 minutes ago, Hawkeye77 said:

 

Falling "out of conformance" doesn't have to be "hotter" and that's not what that says - anyway, the OP was asking generally because of those two situations - more to nonconforming than "hotter".  Not seeing "heavily implied" at all.

They are only doing a CT test which is specifically only testing the face.  A failure means that the CT number was higher and not how it got there.  Usually it is because the face has become hotter due to excessive use and not a specific failure of the head itself.

 

If they were to do a COR test (has to be done at the lab at the USGA), then you could possibly say it was for another reason.

[Socrates]

43 minutes ago, Shallowface said:

Well thanks for correcting me.  I know how much you enjoyed it.

I enjoyed putting the correct information out there.   I don't enjoy bad information, especially when it is being used to promote a false narrative.

[Hawkeye77]

16 minutes ago, Socrates said:

 

They are only doing a CT test which is specifically only testing the face.  A failure means that the CT number was higher and not how it got there.  Usually it is because the face has become hotter due to excessive use and not a specific failure of the head itself.

 

 

So this is the "creep"? 

 

And their statement, lol, is their way of saying they aren't saying with their careful wording, but since it is CT testing we all know what they mean?  Haha, then just say the driver was CT tested.  I thought the testing/inspection also including cracks or other types of degradation, but maybe not.

Edited May 24 by Hawkeye77

[Hawkeye77]

I think I answered my own question - guessing it's the same as at the PGA.

 

https://www.usga.org/content/dam/champ-admin/2024-championship-documents/Notice of Driver CT Testing - U.S. Open.pdf

[Nixhex524]

Cracks would be easily identifiable by the player I would imagine. It's not hard to hear a difference or even notice an inconsistent ball flight.  Especially with how many balls these guys hit on a given day, I would find it the rarity that a crack is the issue that a tour pro would not notice. Super easy to test for at any time, too.   I get why people are arguing sides here but I think we need to stop pretending that the thinner, hotter face is not the issue with these failed tests.  It has to be the majority of the reason the heads fall out of conformity and are taken out of play.  

 

Also, with the access these guys have to technology these days, are we to believe that they don't notice consistently higher ball speed numbers on their quad or trackman during practice?  I know the idea is to protect the player, but are we to believe that they really don't notice something is off?  

[Valtiel]

4 hours ago, Shallowface said:

 

If a pro's clubhead fails, they just go to the trailer and get another one.  Or send someone to the locker for the backup.

 

Not like us where we have to call customer service and then wait for the brown truck.

Logistically sure....but many pros get pretty attached to their gamers and *hate* the idea of having to switch to a backup. I'm sure there are plenty that aren't bothered as much, but Rory, Rahm, Tiger, DJ, and several others with pretty solid speed have lamented losing their "main" driver to things like this. Rahm ever stated once that he hates part of the testing process because he'll get attached to a prototype that he can't actually game. Sometimes it's psychological, but other times you get one that just sits, sounds, feels, and looks perfect that a backup might not for whatever reason.

Edited May 24 by Valtiel

[Socrates]

3 hours ago, Nixhex524 said:

Cracks would be easily identifiable by the player I would imagine. It's not hard to hear a difference or even notice an inconsistent ball flight.  Especially with how many balls these guys hit on a given day, I would find it the rarity that a crack is the issue that a tour pro would not notice. Super easy to test for at any time, too.   I get why people are arguing sides here but I think we need to stop pretending that the thinner, hotter face is not the issue with these failed tests.  It has to be the majority of the reason the heads fall out of conformity and are taken out of play.  

 

Also, with the access these guys have to technology these days, are we to believe that they don't notice consistently higher ball speed numbers on their quad or trackman during practice?  I know the idea is to protect the player, but are we to believe that they really don't notice something is off?  

I would think most of them know very quickly that something is off.  Most of them will start working toward a replacement or even have their head tested by their OEM.  There is a reason they change heads relatively often.  Sometimes it's because something new is there and sometimes they suspect the head is changing and better do it while there is time to get one ready.  Sometimes there are no indicators until it tests over.  Would you notice if you hit your driver 2-3 extra yards?  If I hit my driver 5 yards further one day and I will attribute it to having a good dump that morning. 😉  Gotta be the wheat germ!

[Shallowface]

4 hours ago, Socrates said:

I enjoyed putting the correct information out there.   I don't enjoy bad information, especially when it is being used to promote a false narrative.

I reviewed my earlier post.  

 

I admitted to not being aware of the ongoing process of driver testing on the Tour.  A process characterized by some major publications as "random" and "secretive."  Their words, not mine.

 

And I stated that the USGA has no authority over the PGA Tour.  Nothing false about that.

 

I'm not promoting anything.  But nice try.  You scored three hearts.  Well done. 

[grm24]

4 hours ago, Nixhex524 said:

I know the idea is to protect the player, but are we to believe that they really don't notice something is off?  

In a not subtle way you're accusing tour players of knowingly cheating. Peak WRX.

 

If a driver becomes non-conforming due to CT creep it doesn't magically gain 25 yards.

 

When Xanders driver in 2019 at the Open Championship was deemed non-conforming Chip Brewer of Callaway stated in an article then the difference of the legal CT low/high range (237-259) was around one yard. Others have posted elsewhere it's less than that. 

 

EDIT: IBT the inevitable lock.

Edited May 24 by grm24