Saying the day of reckoning is upon us might be over the top. Still, it is expected that the United States Golf Association and its regulation-making partner, the R&A, will announce changes to the Rules of Golf in the days or weeks ahead that could have significant repercussions for our sport.

Two years ago, shortly before the COVID-19 pandemic began, golf’s governing bodies announced that after significant study, they believed the trend in distance and the lengthening of golf courses was harming the game. Left unchecked, they stated, golf’s environmental footprint would grow too large, and the increasing costs of water and maintenance would damage many facilities. Many people also stated that as elite golfers hit the ball farther and farther, historically significant golf courses that can not be lengthened or changed become obsolete.

The USGA and R&A requested input and feedback from several sources after releasing their 2020 report, and they commissioned studies to learn more about distance from various points of view. Last October they announced the creation of a new Model Local Rule that can be instituted at elite events that would reduce the maximum allowable club-length limit on non-putters from 48 inches to 46. 

Now, equipment companies are waiting to learn what, exactly, the USGA and R&A are planning to announce next. Will the rules that govern clubs be changed? Will the regulations regarding golf ball performance be tweaked? If there are changes, will the USGA and R&A only create Model Local Rules to be adopted at the elite level, essentially creating bifurcation in reality but not in name?

Golfweek asked several engineers at major manufacturers – people who actually design clubs – to answer questions about the effects that widely speculated equipment changes might have on pros and recreational golfers. Four agreed to answer anonymously, while others declined. Below are their answers Golfweek received, edited only for clarity.

The USGA and R&A have created a Model Local Rule to limit club length to 46 inches (for non-putters). How much of an effect on distance do you think it will have?

Bryson DeChambeau drives his ball over the lake on the sixth hole during the final round of the 2021 Arnold Palmer Invitational  at Bay Hill Club & Lodge. (Reinhold Matay-USA TODAY Sports)

Designer 1: Our research and findings concur with what was presented in the Distance Insights Project. The reduction in club length from 48 inches to 46 inches will result in a speed reduction and distance reduction of 3 or 4 yards. Our research also indicates, however, that the length and speed relationship is not linear, so the impact is greater at even shorter lengths.

Designer 2: Overall, I don’t see this as having a massive effect on distance. The number of players who have opted for longer than 46 inches is still relatively small in the grand scheme of things. For those players, it will obviously slow things down, but I don’t see it having a big effect on the overall averages.

Designer 3: Because it is a Local Rule that is going to be used only at elite-player events, it is certainly not going to affect the amateurs. For the tour pros, it depends. There are only a couple of guys that have dabbled in that space of longer drivers. We have had a few staff players tinker around with them. It’s a change of about 3 to 4 mph or ball speed, which at the tour level is about 12 yards.

Designer 4: We know that the effect of the Model Local Rule to reduce the maximum length to 46 inches will have basically zero effect. The average driver length on tour is closer to 45 inches than 46 inches, and almost no players were using drivers longer than 46 inches before the rule came in. We would expect to see zero change in driving distance on tour as a result of this rule change.

What would be the result for pros and recreational golfers if the maximum volume of drivers went from 460 cubic centimeters to 350 cubic centimeters?

Rory McIlroy (Scott Taetsch-USA TODAY Sports)

Designer 1: I’ll pass on this one.

Designer 2: This would have a much larger effect on the recreational players compared to the professionals. It likely wouldn’t even really pull the overall distance back for the pros, but for the recreational guy, this would result in an overall average distance being shorter. Center hits would likely be unaffected, but the size limitation would create lower moment of inertia and coefficient of restitution values that drop off quickly as the face gets smaller. This means the average shot should be shorter.

Editor’s note: Moment of inertia reflects the stability of a driver and its ability to resist twisting. Coefficient of restitution measures how quickly a club’s face snaps back after impact with the ball.

Designer 3: One of the things that we have been studying a lot recently is aerodynamics, and we have found that if you shrink the frontal area of a driver – current drivers have fairly large faces – you will get more speed. So, shrinking the overall volume, at the tour level, could actually increase performance because the drag would be less.

We also find that when you shrink the volume, in general, what you see is a shrinking of inertia, but most tour players hit it fairly close to the center, so it does not drive a lot of performance for their game or mis-hits. So, I don’t think it would have any reduction at the tour level, and for some players, shots could even go further with a smaller driver head.

At the recreational level, it would reduce some of the off-center performance for amateurs. They would give up some speed and lose some stability and control, so it would affect the amateurs much more than the tour players because tour players can easily adapt to small head sizes.

Designer 4: The effect of reducing driver volume will do little to change the distance on center hits but will affect distance mostly through a combination of reducing the moment of inertia, and therefore reducing distance on mishits, and potentially from trying to force golfers to choose to lay up from the tee more often.

What would be the results for pros and recreational golfers if the maximum characteristic time was reduced from 239 microseconds to 200 microseconds?

Phil Mickelson hits driver during a practice round at the 2021 Northern Trust. (David Dusek/Golfweek)

Editor’s note: The characteristic time test measures how long the ball is in contact with the face of a club, effectively measuring the springiness of the face. The longer the ball is in contact with the face, the more energy and speed is transferred to the ball.

Designer 1: The Notice and Comment (of the USGA’s study) proposed a 12-point microsecond reduction, which would render the majority of current drivers on the market non-conforming. The impact would be player-dependent, but the proposed reduction would be a few (2-3) yards. Any additional reductions would result in further reductions in distance for everyone.

Designer 2: This would result in a small but measurable difference for all players. At 100 mph, 18 microseconds equals 0.08 mph of ball speed, so a reduction of 39 microseconds to the rule would mean a speed reduction of about 0.2 mph. If you factor in the manufacturing tolerance, a reduction of 57 microseconds would mean a speed reduction of about 0.25mph. As speed goes up, these values increase. Again, it’s a small decrease, but it is measurable.

Designer 3: Our data shows that about 20 points of CT are equal to 1 mph of ball speed, so dropping from 239 to 200 would cost about 2 mph of ball speed on drivers. For amateurs, 2 mph usually equates to about 5 to 6 yards. At tour speeds, it’s closer to 8 to 10 yards. So we’d see the better players lose some and the average player lose some. In the end, we see the variations in testing with amateurs that there is a pretty high standard deviation, so they might not even notice losing 5 yards, but the better player would.

Designer 4: Characteristic time is intended to correlate with the coefficient of restitution. Our studies showed that to make a large and noticeable difference in distance, the COR (and CT) would have to be reduced a huge amount. [Lowering it to] 200 would be a major change for manufacturers but would not reduce distance by more than a few percent. To bring distance down by 5 or 10 percent would mean reducing CT down to pre-persimmon levels.

What would happen to pros and amateur golfers if the maximum club length was reduced again to 44 inches (for non-putters)?

Designer 1: When discussing driver length in conjunction with distance, consideration must also be given that the longer it is, the higher the chance for off-center hits and greater dispersion. The recently implemented limit on club length (for non-putters) from 48 inches to 46 results in a distance reduction of 3-4 yards. Our research indicates that the length-speed relationship is not linear and that there is an increased impact on the length-speed ratio as lengths get shorter.

Any reductions or caps shorter than 46 inches will result in disruption to the marketplace as all golfers (depending on length) will experience less speed and a reduction in distance.

Designer 2: This is one of the rare ones that might actually hurt the professional more than the average guy. It would likely bring down overall distance for all players. Still, for touring pros who don’t necessarily struggle to find the center [of the face] on longer shafts, their average will probably drop more than the recreational player who [would] likely now find the center more often.

Designer 3: Similar to the reduction from 48 to 46 inches, it would reduce distance a little bit. For some players, it would affect them more and others less. Two to 3 inches in length would probably be 3 to 4 mph ball speed for most amateurs.

Designer 4: Reducing maximum length to 44 inches would likely only affect distance on tour by a couple of yards. Many of the top players and longest hitters already choose to play a driver closer to 45 inches than 46. This change more than most others would affect shorter hitters more than longer hitters.

Is there a change the USGA and R&A could make to equipment that you can think of that would affect elite golfers more than recreational players?

Hideki Matsuyama plays his shot from the third tee during the third round of the 2021 Masters. (Rob Schumacher-USA TODAY Sports)

Designer 1: All proposed changes would impact all golfers.

Designer 2: The overall reduction in driver length is likely the one that would do this. My biggest issue with this is the effect it has on fitting. The average height and build of tour players are getting bigger and taller. For some overly tall players, the reduction in allowable length could be detrimental to them being able to have proper posture.

Designer 3: Going to a lighter golf ball. A lighter golf ball would reduce performance for everybody, but better players are a little more dependent on golf ball performance for their distance component so it would reduce distance for them a little bit more, but these are small numbers. We also know that bifurcation could also work, but some macro spec that changes everybody, we don’t see that there is an opportunity to do that.

Designer 4: Honestly, I’m not sure I want to throw any new ideas into the ring restricting the equipment.

From your experience being around tour players, how long would it take them to adapt to new equipment designed to reduce distance … and how long do you think it might take for club-level golfers to adjust?

Designer 1: Tour players have reached the pinnacle in golf because they have dedicated themselves to being the best they can be and, in most cases, optimized every area of their game to help them perform at the highest level. This includes selecting equipment, launch monitors, full-swing coaches, short-game coaches, sports psychologists, personal trainers and nutritionists, among other things that they believe will help them achieve their goals. If a piece of equipment – a tool of their trade – is altered, that impacts an important aspect of what they have worked on for years to perfect. Like anything else, some will adapt quicker than others. Depending on the extent of the change, some will have difficulty and never fully adapt. The impact and timeline are player-dependent.

As for club-level golfers, many are still currently able to play and enjoy the game, thanks to technology. If they are forced to hit the ball shorter and if the game becomes more challenging, many would find the game to be less enjoyable and would likely play less.

Designer 2: Tour players will adapt immediately. They will find ways to still hit [new clubs and balls] long. I would expect the overall impact of the changes to have a really minimal effect on professional golf as it’s viewed by everyday watchers. The long guys will still be unbelievably long. Course setup will dictate how they play.

Designer 3: Tour players would range from most adapting rather quickly to some guys figuring it out in a month or two. I don’t think it will take the tour players long. Remember, they practice every day. They have launch monitors right there and a coach who helps them to fine-tune their swing. Their swings will be much easier to adjust than an amateur’s.

Designer 4: Honestly, I think tour players would adapt very quickly to new regulations. It does somewhat depend on exactly what new regulations are enacted, but I feel like top players would adapt very well within a couple of weeks, no matter what. More tricky would be to go back and forth between two types of regulations (if there were some kind of bifurcation), but even then I feel like it is possible for top players. Top tennis players do it all the time, as do professionals in other sports. Less skilled players would take longer to adapt.

If the USGA and R&A mandate a change in the performance of golf balls by making them larger or less aerodynamic, how would that affect elite golfers and weekend players?

Golf balls stacked in a pyramid on a driving range. (Golfweek)

Designer 1: The golf ball has been highly regulated for decades with limits on size, weight, symmetry, initial velocity and overall distance. The line in the sand was drawn with the updated Overall Distance Standard protocol in 2003, and it has worked by the leveling of distance at the elite level over the past 15 years. There has only been a 6-yard increase in average driving distance on the PGA Tour since 2006.

A change in the size and/or aerodynamics of the golf ball would result in a reduction in performance and distance for all golfers, from the elite to the weekend player. The extent of the rollback would be player-dependent based on speed and launch conditions. However, the negative impact is largely linear.

Designer 2: This would likely have a bigger effect on the elite players as well. There could be noticeable differences when speed is higher and less noticeable differences when it’s lower.

Designer 3: We think that any changes in the specifications of golf balls would affect every player, probably in a linear fashion. For example, if I gave a club that goes faster to a player that swings at 100 mph and another that swings at 130 mph, it’s going to be linear in what they get, but the guy swinging at 130 mph is still going to be longer than the guy swinging at 100. But this would be on a percentage basis, so the long hitters are going to lose more, but it’s really going to be at the same percentage.

Designer 4: Our data shows that restricted distance golf balls, whether it be through ball radius or ball mass or aerodynamics, would affect longer hitters disproportionately more than shorter hitters. However, there are other consequences. A lighter or larger ball would be more affected by the wind and would make it more difficult to control, as well as shorter. It would also be more susceptible to start rolling on the green in the wind, which could be a problem. There is precedent for this in the past. In the 1930s there was a full season of golfers using different size balls on the course. In the end, the USGA settled on the 1.68-inch ball and the R&A settled on the 1.62-inch ball. My understanding is they were more concerned about balls rolling around on greens in the wind. It wasn’t until the 1970s that the British ball was changed to match the American ball.

Some people have put forth the idea that simply bifurcating the rules could solve a lot of problems. From a business standpoint, how would bifurcation help or hurt your company?

Tiger Woods plays the10th during a pro-am round of the 2022 PNC Championship at Grande Lakes Orlando. (Jeremy Reper-USA TODAY Sports)

Designer 1: At my company, we’re advocates for a unified game with all golfers in all countries playing by the same rules and equipment standards. This is a key component of the game’s enduring and aspirational appeal. Differing equipment standards, based on the level of skill, will sever one of the great attributes of the game, which has unified the game throughout history.

At what level would there be different equipment standards? What about juniors, college players, mid-ams and club professionals aspiring to qualify for the U.S. Open, the British Open or to play on one of the professional tours? Would those golfers be required to purchase different equipment for different calibers of play? The cost to golfers would escalate substantially, as would the complexity for the golf professional and retail community.

The design and manufacturing of equipment would become more complex and costly as products are developed on parallel paths.

Designer 2: As a company, it would likely have a small impact, with an increased number of SKUs and additional time and resources required to develop two sets of products, however it would ultimately come back on the consumer who would be charged more for everything.

The smaller quantities demanded for the “Tour” level stuff would mean higher costs due simply to the economies of scale. Additionally, the “handcuffs-off” version of traditional clubs would likely lead to new technologies, materials and manufacturing processes that would, again, drive the price to the consumer up.

Overall, the pros are the pros for a reason. They’re going to figure out exactly how to get the most out of whatever they are allowed to use. It’s important to remember as well that the PGA Tour and LPGA are ultimately about entertainment value. If everything were dialed back, so every course played as hard as a U.S. Open, viewership would go down. Once that happens, course setups would change to encourage more excitement, whether it be shorter holes or easier pins or something else. People like watching birdies and low scores. There’s a reason everyone loves the back nine at Augusta. Anyone (golfer or not) can appreciate watching the charge. If you sit a non-golfer down to watch the players chipping out sidewise and hoping to get up and down out of the rough at Shinnecock, you’re going to lose them.

Designer 3: It would be a challenge because we would have to make additional toolings for drivers, inventory those parts and manufacture them, so those are added business costs, but they are not huge. Many companies already make separate tools for tour-player products. It’s not something we don’t do already, but it could cause some confusion in the marketplace, especially at the elite amateur levels. Will college kids have to play this stuff? What about the club champions at the local clubs? Those types of players might want to have, or have to have, two sets of clubs created to different performance specifications. But we see this in other sports, like baseball, where if you are a professional player you have to use a wooden bat and at some levels of amateur play you can use an aluminum bat.

Designer 4: Bifurcation could certainly be a blessing and/or a curse. Taken in the positive, it is a chance to optimize equipment for professionals and recreational golfers separately. It’s a new challenge for the team.

However, it takes a lot of time and testing to develop new golf clubs. There would need to be a long lead time, and the R&D investment in clubs for the professionals would not be recouped directly. It would effectively double the research and development activities to design and develop two lines of clubs. There would also be uncertainty around who is using (and maybe buying) the “pro” clubs. Do some golfers need two sets of equipment? Confusion is generally not a good thing in the marketplace.

This article originally appeared on Golfweek.