The groove rule and the ball rollback

[Maine Golfer]

I dont swing super fast, ill be messing around with balls more this year. I like how tour balls feel on my wedges, thats the best part of my game and I feel it helps me when they are higher end and bite on command. But almost sure I do better off the tee with Rush's. 

 

 

[davep043]

9 minutes ago, betarhoalphadelta said:

Not sure how that works that distance loss isn't proportional and somehow only affects driver, not irons.

I can't say I've seen this claim, do you have a reference?

10 minutes ago, betarhoalphadelta said:

This is despite the fact that there is no mention anywhere that a ball manufacturer has submitted a premium ball meeting the new standard to the USGA/R&A for testing.

I believe there are reasonably well-understood correlations between ball speed, backspin, launch angle, and distance, things like the Trackman Optimizer.  It seems reasonable to use those correlations in making preliminary estimates of the changes due to the revised testing procedure.  I doubt they've had the opportunity to test prototypes of premium balls which meet the new criteria, so they use the available science.

 

[storm319]

13 minutes ago, ThinkingPlus said:

That's for all swing speeds if you actually want irons to spin as well. In a world where cost isn't  an issue, everyone, except the "must have a soft feeling ball" players, would use tour balls. At least that is what the test data pretty much shows.

Exactly. There is no performance benefit to playing a lower compression ionomer covered ball regardless of swing speed (there may be extremely high spin outliers where the lower spin benefit outweighs the ball speed loss, but those examples are extremely rare). Essentially cost/feel preference would be the reason for this choice at the expense of general performance.

[bekgolf]

2 hours ago, Augster said:

That’s a list of conforming balls. It’s not performance data within that list to find out which balls perform better or worse than others. 
 

When the new standards come out, there will also be a conforming list. And many of the balls on this list will move to non-conforming at that time. But not all of them. 

 

All I've said I wanted to see is the list of balls they tested that would pass the new requirements.  I asked for that information (data) because I'm of the belief that they have extrapolated the figure of 30% from existing data/testing.

 

There is another site that tests how well balls perform, I'd never expect the USGA to provide such information and I'm not sure how you got that from my posts.

[Socrates]

18 minutes ago, bekgolf said:

 

All I've said I wanted to see is the list of balls they tested that would pass the new requirements.  I asked for that information (data) because I'm of the belief that they have extrapolated the figure of 30% from existing data/testing.

 

There is another site that tests how well balls perform, I'd never expect the USGA to provide such information and I'm not sure how you got that from my posts.

I guess, whenever they feel like they need to provide that data, they will.  No point in worrying about it for at least 3 years.

[bekgolf]

Just now, Socrates said:

I guess, whenever they feel like they need to provide that data, they will.  No point in worrying about it for at least 3 years.

 

Stop making sense!  Lol.  I really wish I had that ability, life would be much easier.

[Halebopp]

1 hour ago, storm319 said:

Not saying they are lying about it, but they also are not clear if the testing that they perform ends up on the official conformance lists (whereas there are videos of the USGA performing the actual ITR/ALC tests). 

 

Your comment, to which I first replied, was that the USGA does all the equipment conformance testing. The R&A equipment testers say they do all sorts of conformance testing.

 

Both of those sentences cannot be true.

 

If there's a difference in how much material there is available about the actual tests, I'm fairly certain it's simply down to the budget and resources available to the two organizations and how they've preferred to allocate them.

[iacas]

13 hours ago, storm319 said:

the whole reason that they abandoned the MLR proposal was due to the PGA Tour/PGA of America’s intention to not apply the MLR for their competitions if the proposal was adopted

 

Manufacturer push-back was a bigger part of it. The PGA Tour would have likely gone along with it if they had pushed through.

 

1 hour ago, betarhoalphadelta said:

Because they apparently have come up with a magic ball that will take 9-11 yards off driver for high speed players, only 4 yards off driver for average speed players, and magically not take any yards off irons for average speed players. Not sure how that works that distance loss isn't proportional and somehow only affects driver, not irons.

 

Because performance isn't perfectly linear.

[betarhoalphadelta]

2 hours ago, davep043 said:

I can't say I've seen this claim, do you have a reference?

 

 

 

https://golfweek.usatoday.com/2023/12/06/usga-ra-golf-ball-rollback-professionals-amateurs/

 

“The longest players, which means those generating ball speeds of 183 mph or higher, are going to lose 13 to 15 yards [with their driver],” Pagel said. “The average PGA Tour player and elite male, like a college player, would lose closer to 9 or 11 yards. LPGA players, given their clubhead speed, we’re looking at 5 to 7 yards. And recreational golfers, we’re talking about 5 yards or less.” 

 

Only 10 players ended last season’s PGA Tour with a measured ball speed average of over 183 mph. ShotLink reports the PGA Tour’s average ball speed for the season was 172.85 mph.

 

According to John Spitzer, the USGA’s director of equipment standards, the average male club player who swings his driver at 90 mph will lose 4 to 5 yards off the tee but will likely not lose any yardage when hitting hybrids, irons or wedges.

 

I don't know how they can state that you'll lose driver distance but no distance from other clubs. 

 

 

 

[betarhoalphadelta]

44 minutes ago, iacas said:

 

Because performance isn't perfectly linear.

 

Or potentially because their assumption is that lower-speed players are playing marshmallows, despite the test results popularized by that big biannual ball test done by the other site showing that most players benefit from a higher-compression premium ball. 

 

I'd probably buy that if you're swinging 100 mph or less and you're playing a marshmallow, maybe you won't lose as much proportionally as a higher-speed player playing a higher-compression premium ball. But I'm not sure that I buy that if you're 100 mph or less and playing said premium ball, that you won't lose distance proportionally to a higher-speed player. 

[Halebopp]

2 hours ago, betarhoalphadelta said:

 

Because they apparently have come up with a magic ball that will take 9-11 yards off driver for high speed players, only 4 yards off driver for average speed players, and magically not take any yards off irons for average speed players. Not sure how that works that distance loss isn't proportional and somehow only affects driver, not irons.

 

This is despite the fact that there is no mention anywhere that a ball manufacturer has submitted a premium ball meeting the new standard to the USGA/R&A for testing. If the balls which currently conform are 2 pc marshmallows with poor spin characteristics and THESE are the balls they used for testing, the testing is irrelevant, as they aren't representative of what premium balls meeting the new standard will look like. 

 

In short, the USGA/R&A have made a lot of statements about what these new balls will look like and have provided NO evidence justifying those statements. It's just been "trust us". The whole thing gives off a vibe that they made the decision to roll back the ball and they're reasoning back from that to try to assuage average golfers that this won't affect them. Then in 2028-30 when it does? "Sorry, but them's the breaks. The rule is already in place."

 

You talk about magic when it's merely physics, transfer of energy, collissions, elasticity etc.

 

The reason someone with a slower swing speed with the driver will lose relatively less distance than you is the same reason why you lose less distance with an iron than with your driver.

 

The harder the ball core is, the more energy is needed to properly compress it to get the best possible energy transfer to the ball. You can't get the same with your iron, just like the player with the slower swing speed can't do it with the driver.

 

Never mind the physics after the strike itself, the faster the ball travels, the greater the air resistance. If you double the velocity of the ball, you quadruple the air resistance. A 30% increase in initial ball velocity increases air resistance by 70%.

 

Also, they're only changing certain parameters of the test. Current Pro V1 is similarly limited in comparison to balls that would be illegal now as the future balls will be limited when compared to a current Pro V1. Rest assured an unlimited ball would provide the biggest gains to those who can swing the club the fastest.

[betarhoalphadelta]

13 minutes ago, Halebopp said:

 

The reason someone with a slower swing speed with the driver will lose relatively less distance than you is the same reason why you lose less distance with an iron than with your driver.

 

The harder the ball core is, the more energy is needed to properly compress it to get the best possible energy transfer to the ball. You can't get the same with your iron, just like the player with the slower swing speed can't do it with the driver.

 

 

Yes, I completely agree that the higher-speed will lose more yards than the average speed player. However, I haven't seen evidence to make me accept that the higher-speed will lose a higher percentage of their distance than the average speed player. 

 

Perhaps the USGA/R&A have this evidence. They certainly haven't shown it to anyone that I'm aware of. They made the assertion and have not backed it up. 

[iacas]

1 hour ago, betarhoalphadelta said:

Or potentially because their assumption is that lower-speed players are playing marshmallows, despite the test results popularized by that big biannual ball test done by the other site showing that most players benefit from a higher-compression premium ball.

 

I meant what I typed: it's not linear.

 

57 minutes ago, betarhoalphadelta said:

Yes, I completely agree that the higher-speed will lose more yards than the average speed player. However, I haven't seen evidence to make me accept that the higher-speed will lose a higher percentage of their distance than the average speed player. 

 

Perhaps the USGA/R&A have this evidence. They certainly haven't shown it to anyone that I'm aware of. They made the assertion and have not backed it up. 

 

They have evidence, and I'd be repeating myself again… it's not linear. It'd be wacky as heck if it was over a decent delta in ball speeds.

[Halebopp]

1 hour ago, betarhoalphadelta said:

 

Yes, I completely agree that the higher-speed will lose more yards than the average speed player. However, I haven't seen evidence to make me accept that the higher-speed will lose a higher percentage of their distance than the average speed player. 

 

Perhaps the USGA/R&A have this evidence. They certainly haven't shown it to anyone that I'm aware of. They made the assertion and have not backed it up. 

 

Why don't you believe them? Have you studied physics at university to the level you can dispute them?

 

I've only done the basics of university physics so my abilities to explain the issue are too limited to even try. But in short, it's what iacas has said a couple of times, it's not linear.

 

Current limitations to the ball hurt players with high swing speeds relatively more than players with slower speeds and so will the upcoming limitations. Nothing is changing in that regard.

 

I guess the best advice I can give you is to go to a simulator that measures actual ball speeds and play around with different balls and different clubs.

[betarhoalphadelta]

1 hour ago, iacas said:

 

They have evidence, and I'd be repeating myself again… it's not linear. It'd be wacky as heck if it was over a decent delta in ball speeds.

 

If they have evidence, they haven't shown it. Perhaps that's because they know everyone who is anti will do everything they can to pick it apart even if their evidence is ironclad. Perhaps that's because it's very limited and it can easily be picked apart. 

 

But everything about this has smelled like they reached the conclusion and they're working backwards from it to rationalize it. 

 

If average players were never going to notice the rollback, then why did they need to propose an MLR for elite male golfers? 

 

37 minutes ago, Halebopp said:

 

Why don't you believe them? Have you studied physics at university to the level you can dispute them?

 

I've only done the basics of university physics so my abilities to explain the issue are too limited to even try. But in short, it's what iacas has said a couple of times, it's not linear.

 

Current limitations to the ball hurt players with high swing speeds relatively more than players with slower speeds and so will the upcoming limitations. Nothing is changing in that regard.

 

I guess the best advice I can give you is to go to a simulator that measures actual ball speeds and play around with different balls and different clubs.

 

I have a level of distrust because they have seemed to be very questionable in the way that they've sold this the entire time. There's a HUGE thread on this in the "Tour Talk" subforum where you can see quite a bit of what I've said on the subject. However, to put it simply, they said there was a problem with distance related to elite male golfers. Their solution, they say, won't affect regular speed golfers. Yet their interim solution was an MLR that was only affecting elite male golfers. If they didn't believe their solution would affect regular speed golfers, why would the solution need to be proposed as an MLR? 

 

Admittedly, my expertise is electrical engineering, not mechanical or aeronautical. I've taken undergrad calculus-based physics (mechanics* one semester, E&M the second semester), but was not requited to take classes like thermodynamics or anything specializing in aerodynamic forces beyond the basic point that you already cited that drag is proportional to the square of velocity. And also that things get WAY more complex once a ball starts spinning due to the Magnus effect. 

 

BTW simulator data is questionable. A simulator like Trackman (as far as I'm aware) isn't going to have a bunch of aerodynamic models for every ball on the market. My understanding is that the aerodynamic model is the same no matter what ball you hit. So if you hit two balls with very different dimple patterns and very different aerodynamic properties with the same launch characteristics (speed, angle, spin, etc) it will show you on the screen that they fly identically--even if that isn't true in the real world. 

 

Spoiler

 * Full disclosure--I did not actually take mechanics at my alma mater. I took AP physics in HS. I got 5s on both parts of the AP Physics test. They wouldn't accept the mechanics portion of the AP test by itself (they use that physics class as a weed-out class for engineers), so they made me take the final in the summer prior to my freshman year, and I passed, so they gave me the credit. Since I was intending to go into electrical engineering, they wouldn't even let me attempt to test out of the E&M portion under any circumstances, so I took that class in both HS and college--I got an A both times.

 

Edited January 5 by betarhoalphadelta
left out the Magnus effect the first time

[rogolf]

Let's remember that this is a joint initiative by the USGA and the R&A.  Criticizing one is criticizing both.

Have a look at these references for Dr. Steve Otto, R&A Equipment Standards division

https://www.theguardian.com/sport/2006/jan/11/golf.gdnsport3

https://www.researchgate.net/profile/Steve-Otto-2

[iacas]

32 minutes ago, betarhoalphadelta said:

If they have evidence, they haven't shown it.

 

Who isn't showing it? The USGA/R&A? They actually have, in the past, showed these types of things:

 

 

That's a USGA example from the early 2000s.

 

But here's the more important point: they don't have to "show" you the evidence… because it's physics/aerodynamics/etc. Performance isn't linear.

 

The graph I faked a page or two ago isn't that far off of what we see in reality.

 

34 minutes ago, betarhoalphadelta said:

If they have evidence, they haven't shown it. Perhaps that's because they know everyone who is anti will do everything they can to pick it apart even if their evidence is ironclad. Perhaps that's because it's very limited and it can easily be picked apart.

 

Perhaps it's just that it'd be a waste of time, given that it's well understood to be true. "Oh my, the USGA didn't put out evidence that 2+2=4, what are they hiding!?!?"

 

34 minutes ago, betarhoalphadelta said:

But everything about this has smelled like they reached the conclusion and they're working backwards from it to rationalize it.

 

We seem to have reached the "You can't reason someone out of a position they didn't reason themselves into." part of this discussion. 😀

 

34 minutes ago, betarhoalphadelta said:

If average players were never going to notice the rollback, then why did they need to propose an MLR for elite male golfers?

 

I'm not going to speak for them, but Mike Whan has been on some podcasts lately, so maybe listen to those?

 

34 minutes ago, betarhoalphadelta said:

Their solution, they say, won't affect regular speed golfers.

 

No, they say it won't affect them much.

[storm319]

4 hours ago, Halebopp said:

 

Your comment, to which I first replied, was that the USGA does all the equipment conformance testing. The R&A equipment testers say they do all sorts of conformance testing.

 

Both of those sentences cannot be true.

 

If there's a difference in how much material there is available about the actual tests, I'm fairly certain it's simply down to the budget and resources available to the two organizations and how they've preferred to allocate them.

I was referring to testing for the ball list since that is the primary topic of this thread, but probably should have clarified so I apologize (although clubs are not technically tested by the RBs, simply certain physical attributes measured unless you consider measuring CT to be a test). 
 

Also, there are different types of conformance testing. For instance, you can submit your own personal clubs to either RB to have the grooves checked for conformance, but this does not impact any of the conformance lists referenced by the ROG. Now I could be mistaken but it was my understanding that the USGA solely maintained the conforming ball list since the inception of the ODS and I cannot find any evidence to the contrary (and definitely too lazy to reach out the R&A directly to confirm their role in testing 🙂 ).

[storm319]

5 hours ago, iacas said:

 

Manufacturer push-back was a bigger part of it. The PGA Tour would have likely gone along with it if they had pushed through.

I strongly disagree. Watch this interview with Mike Whan at around the 10 min mark. The MLR approach was effectively killed due to the concern that it would not be applied consistently at the levels of play that this was intended for.

 

 

[iacas]

17 minutes ago, storm319 said:

I strongly disagree.

 

Okay.

[betarhoalphadelta]

16 hours ago, iacas said:

 

Who isn't showing it? The USGA/R&A? They actually have, in the past, showed these types of things:

 

 

That's a USGA example from the early 2000s.

 

But here's the more important point: they don't have to "show" you the evidence… because it's physics/aerodynamics/etc. Performance isn't linear.

 

 

Funny... That graph looks VERY close to linear. Yes, the slope might drop off a little bit after 110 mph, but certainly not enough to think that the fastest players will lose close to twice as much distance percentile-wise as average speed swingers. 

 

Quote

Perhaps it's just that it'd be a waste of time, given that it's well understood to be true. "Oh my, the USGA didn't put out evidence that 2+2=4, what are they hiding!?!?"

 

The graph above shows that distance is very close to linear wrt swing speed. If so, the distance loss would be expected to be very close to linear on a percentage basis wrt swing speed.

 

[Simpsonia]

22 minutes ago, betarhoalphadelta said:

 

Funny... That graph looks VERY close to linear. Yes, the slope might drop off a little bit after 110 mph, but certainly not enough to think that the fastest players will lose close to twice as much distance percentile-wise as average speed swingers. 

 

 

The graph above shows that distance is very close to linear wrt swing speed. If so, the distance loss would be expected to be very close to linear on a percentage basis wrt swing speed.

 

 

Yep, while it may not be exactly linear, it can still be very close to linear. From the very early USGA ball tests the fastest swingers lost 8.5% while the slowest swingers still lost 7%. So not exactly a linear reduction, but nowhere near the magic ball being sold by the USGA. 

 

Also in a very interesting difference, the USGA test ball reached its optimal distance at ~2800 rpm. If the ball manufacturers follow this design trend, it's going to require different drivers to optimize for a much higher spin than the current balls. 

Edited January 6 by Simpsonia

[Shilgy]

On 1/4/2024 at 11:37 AM, iacas said:

 

It's not "guessing." Some balls are optimized for people who swing their drivers at 90 MPH, or who want other characteristics from their golf ball.

 

 

They're not going to release a list. It's not their place to do so, and manufacturers would have a legitimate beef if they did.

 

I've talked to ball engineers, etc. and won't be releasing my own list, either… but it's been stated more than a few times what types of balls you should look at if you want to understand what types of balls already conform.

 

Consider that aerodynamically you can have a ball performance (with respect to distance) "fall off" a bit more than linearly. Some balls will be closer to linear than others, and a ball that performs well at lower speeds might fall off a bit more at higher speeds.

 

Consider that you could have two balls that perform like this, where the blue one is better for higher clubhead speeds (X axis), and the green one is better for lower clubhead speeds.

“Better” as in longer?  What speeds to the two lines represent?  I wouldn’t think they could be very far apart for the slower speed to be “better” with any ball.

[iacas]

6 hours ago, betarhoalphadelta said:

Funny... That graph looks VERY close to linear.

 

IIRC, that's one ball… and it's not linear. Clearly.

 

6 hours ago, betarhoalphadelta said:

Yes, the slope might drop off a little bit after 110 mph, but certainly not enough to think that the fastest players will lose close to twice as much distance percentile-wise as average speed swingers.

 

It's about a sub-5% reduction at the very top-end. So could it be only a 3.5% reduction at the lower end? Absolutely.

 

12 minutes ago, Shilgy said:

“Better” as in longer?  What speeds to the two lines represent?  I wouldn’t think they could be very far apart for the slower speed to be “better” with any ball.

 

The two lines are two balls, one optimized for lower clubhead speeds (left on the x axis) and the other better for faster head speeds (right).

 

Fact: a ball's response to clubhead speed is not linear.

[Shilgy]

11 minutes ago, iacas said:

 

IIRC, that's one ball… and it's not linear. Clearly.

 

 

It's about a sub-5% reduction at the very top-end. So could it be only a 3.5% reduction at the lower end? Absolutely.

 

 

The two lines are two balls, one optimized for lower clubhead speeds (left on the x axis) and the other better for faster head speeds (right).

 

Fact: a ball's response to clubhead speed is not linear.

I’m not questioning the last bit.  I would just like to know at what respective speed is better slower?  Or actually by how much?  Meaning I am doubting a ball exists that is better with 85mph swing than 120mph.  And am guessing that a slower speed might be better if launch and spin are optimized than a slightly higher speed that is not optimized.

 

Bottom line I very much dislike a graph that tells you nothing but a picture….no stats showing what it represents.

[betarhoalphadelta]

50 minutes ago, iacas said:

 

IIRC, that's one ball… and it's not linear. Clearly.

It's about a sub-5% reduction at the very top-end. So could it be only a 3.5% reduction at the lower end? Absolutely.

 

 

Yes, it's not linear. But it's close. It doesn't show that distances completely fall off at higher clubhead speeds such that there's a point of diminishing returns. 

 

There is a VERY SLIGHT reduction in slope beyond 110 mph. 

 

Quote

 

The two lines are two balls, one optimized for lower clubhead speeds (left on the x axis) and the other better for faster head speeds (right).

 

Fact: a ball's response to clubhead speed is not linear.

 

 

The two lines are two balls that you completely made up, right? Did you give that graph to the USGA to inform their findings? 😉 

 

The other site that rates balls has a fair bit of data showing that there aren't really all that many balls "optimized for lower speeds" despite what the ball manufacturers suggest. The premium balls that give the most distance for high speed players (albeit not the ones optimized for low spin) tend to give similar driver distance for lower-speed swingers as the marshmallows, but offer better approach and greenside characteristics because the higher compression leads to more spin. 

 

In fact, their testing essentially shows that a "soft" ball is basically worse for all players. 

 

But hey, maybe the USGA/R&A are basing their findings on the idea that lower-speed players are [incorrectly] playing marshmallows, so they won't see a reduction. If that was their assumption, you'd think maybe it would be worth mentioning... 

[iacas]

32 minutes ago, betarhoalphadelta said:

Yes, it's not linear.

 

I'm glad we agree on the facts. 🙂 

[betarhoalphadelta]

10 minutes ago, iacas said:

 

I'm glad we agree on the facts. 🙂 

Yes.

 

Which is why I assume, as someone without PGAT speed, that if the PGAT guys are losing 9-11 yards, I'll lose 7-9 yards with driver. 

 

And probably a couple of yards with irons.

[iacas]

Just now, betarhoalphadelta said:

Yes.

 

Which is why I assume, as someone without PGAT speed, that if the PGAT guys are losing 9-11 yards, I'll lose 7-9 yards with driver. 

 

And probably a couple of yards with irons.

 

Again, I've never said (nor has the USGA/R&A) that average players will be completely unaffected.

 

On 1/5/2024 at 5:31 PM, iacas said:

On 1/5/2024 at 4:49 PM, betarhoalphadelta said:

Their solution, they say, won't affect regular speed golfers.

 

No, they say it won't affect them much.

 

If you want to argue about what "much" is, I'm out. Move the tees up five yards if it matters that much to you.

[CDLgolf]

On 1/5/2024 at 2:24 PM, betarhoalphadelta said:

 

https://golfweek.usatoday.com/2023/12/06/usga-ra-golf-ball-rollback-professionals-amateurs/

 

“The longest players, which means those generating ball speeds of 183 mph or higher, are going to lose 13 to 15 yards [with their driver],” Pagel said. “The average PGA Tour player and elite male, like a college player, would lose closer to 9 or 11 yards. LPGA players, given their clubhead speed, we’re looking at 5 to 7 yards. And recreational golfers, we’re talking about 5 yards or less.” 

 

Only 10 players ended last season’s PGA Tour with a measured ball speed average of over 183 mph. ShotLink reports the PGA Tour’s average ball speed for the season was 172.85 mph.

 

According to John Spitzer, the USGA’s director of equipment standards, the average male club player who swings his driver at 90 mph will lose 4 to 5 yards off the tee but will likely not lose any yardage when hitting hybrids, irons or wedges.

 

I don't know how they can state that you'll lose driver distance but no distance from other clubs. 

 

 

 

 

How do they know this ? Have they manufactured  the new balls or are they just speculating.