Golf Technology Forecast - 2008

Dave Tutelman  -  May 15, 2008

This year Tom Wishon gave the keynote speech at the World Scientific Congress of Golf V. His topic was "Past, Present, and Future of Golf Club Technology." (See this link for a video of his complete speech.) I felt he did a fine job on the past and present, but I had a somewhat different take on the future. (Of course, all technology forecasters have minor or major disagreements -- there's that old saw about "difference of opinion is what makes horse races." It's healthy.) Anyway, I decided to record my take on it.*

There is one important aspect of Wishon's forecast that I'd like to use as a starting point for my own. The major theme of his forecast is that the big, untapped area in club and ball technology is custom fitting, and that is where most future advances will take place. I like that! I don't know whether it's because I believe it or just that I'd like to believe it. But let's start with that notion, and see where my own forecast goes with it...

Why fitting -- and why not

First, why is clubfitting technology the next thing that will be called into importance? (Wishon touched on some of this in his talk.) The answers are Rules and Other Limits. Most technology advances in golf clubs have been applied to making things bigger, lighter, higher-energy-transfer, or higher-MOI. That's not just the past decade, when tech advances have been visible, widely advertised, and explicit. If you look at every golf technology advance in the past century, it has been either one of the above, or the ability to manufacture consistency at a reasonable price (e.g.- the steel shaft replacing hickory).

We are close to the end of the line for bigger, lighter, higher-energy-transfer, and higher MOI. Consider:
So advances in fitting equipment to golfers is where we will see technology applied best, by a process of elimination. We are past the era of absolute differences in performance -- technology that improves performances for all golfers. What is left is technology to match different club and ball specs to the individual golfer.

But there's also a "why not?" aspect to this. Or maybe two:

 TaylorMade
ICW (1994)
[avg golfer]		 TaylorMade
RAC-OS(2004)
[avg golfer]
3-iron 22 20
4-iron 25 23
5-iron 29 26
6-iron 33 29
7-iron 37 33
8-iron 41 37
9-iron 45 41
PW 49 45

  1. You will hear about the huge technology advances in golf clubs with every new wave of models introduced. It is possible that some will actually have technology advances worth talking about. Most will not! Most of those advances -- like most of the advertised "advances" of the past decade -- will be puffery, pure and simple. There have been lots of highly-touted (and widely spent-upon) features of the past 10-20 years that provided only a minimal improvement or, worse, no real improvement at all.
    Consider a case in point: the gain of a full club of distance in the irons over ten years. There is no doubt that this has happened -- that today's 7-iron hits the ball as far as yesteryear's 6-iron. But why? Technology? Nope! The table shows the loft specs I pulled from the TaylorMade web site, for their "average golfer" irons from the years of 1994 and 2004. The loft changes alone would account for nearly a club's increase in distance. If you factor in that the "standard" length of an iron has increased a half inch over that time, you completely explain the increase in distance. In fact, today's 7-iron is yesteryear's 6-iron. Technology indeed!
    (BTW, TaylorMade was hardly the only company to be involved in these "loft wars", nor were they the first, nor were they the worst offenders. They just happened to be where I found supporting data first.)
  2. Real custom clubfitting may not happen on a large scale, in which case the technology to enable it will not be needed. Tom Wishon is optimistic that the industry -- and particularly customers -- will embrace clubfitting. I see little evidence to support that yet. The big name brands continue to sell by advertising and endorsement, and pay only lip service to custom fitting. They have the motivation not to allow a foothold for the independent clubfitting expert. So it is far from certain that effective custom fitting will become the norm in the future.
There is some question that the bulk of technology advances in the foreseeable future will involve fitting golfers to clubs or balls. Nevertheless, it is intriguing enough that I am as willing as Wishon to let it be the theme for this look at future technology. So let's proceed.

Science is not technology

Before we start forecasting, let's draw a distinction between science and technology. A quick and glib distinction would be, "Science is knowledge, technology is know-how." But I think we would be better served with an example.

For a long time, science has told us that we could get straighter drives if we increased the moment of inertia of the driver head. Science also told us how to do that: make the clubhead bigger at the same weight. The weight has to stay the same because other studies (more science) tells us that 7 ounces (200 grams) is about the right mass for a driver head; more or less mass would lose distance. So we can't add weight to the clubhead in order to increase the moment of inertia; we have to find a way to move the weight that's there farther away from the middle of the head.

So we had the science -- the raw knowledge. But, until the 1990s, we did not have the technology to actually build clubheads much larger at the same weight. Stainless steel heads had a somewhat higher MOI than did wooden heads. But the strength-to-weight ratio of stainless steel was limited. It was hard to build a driver head at a size of more than 250cc.

In the 1990s, aerospace technology was suddenly available to the golf industry for a variety of reasons, both technological and political. That meant that titanium clubheads became a practical possibility. Titanium has the strength of steel at half the weight. Bingo! It was suddenly possible to apply technology to the problem. The science had been around for a long time, but finally the technology caught up. Today most driver heads are high-MOI with a volume of 460cc (the legal limit under the Rules of Golf).

We are going to do some technology forecasting here. But we are also going to point out a few science problems that need to be solved. In many ways, the limits of technology and limits imposed by the rules require our turning to science -- to better understand the problem -- rather than just applying the technology at hand.

The combinatorics problem

The ground rules I've agreed to are that the main area for advances will be in clubfitting. And one of the biggest problems faced by clubfitters is "combinatorics". A significant part of the clubfitter's job is to have the golfer try out a club of the specifications suggested by measurement of the golfer and his/her swing. In order to be able to try things out, the clubfitter must have in inventory a club that meets those specs. And coming up with such an inventory is an exercise in combinatorics.

Consider the following -- oversimplified -- problem. Suppose the clubfitter has six different driver heads that might be needed as test clubs. These heads span the specifications of weight, loft, size, etc. (Six is clearly an unrealistically small number. But let's use it just for the sake of keeping the arithmetic easy.) Also, there are six shafts that "span the fitting space" for drivers -- again, not nearly enough for realism. How many test clubs would the clubfitter need to stock, in order to be able to test any combination on a customer being fitted?

The answer is multiplicative; that is, you have to multiply the head choices by the shaft choices. For each of the six heads, there are six shaft choices that you might need. So this very oversimplified model still requires six times six equals thirty-six test drivers to do the fitting.

Now, what would be a more realistic number? Let's look at all the specs for the head that we might want to play with:
  • Loft: maybe 5 different lofts.
  • Weight: maybe 6 weights.
  • Weight distribution: maybe 6 CG placements.
There are probably more, but let's stop here. Since the choices are multiplicative, we need not six heads, but 5x6x6=180 heads. That's 180 different heads.

Remember that the problem is also unrealistic for six shafts. How about five different flexes (probably very optimistic), times three different flex profiles (definitely too optimistic), times four weights, times six lengths. That's 360 different shafts.
When we look at combining 180 different heads and 360 different shafts, we have 64,800 test drivers. Even if we can eliminate 3/4 of them as silly combinations (because, for instance, you probably would never encounter a golfer whose ideal driver is an 8° loft with an L-flex shaft), we are still left with over 10,000 test drivers. And we haven't started to talk about test irons, wedges, putters, hybrids...  Yeah, right!
 
So what can technology -- or science, for that matter -- do about the combinatorics problem?
 

Shaft-head connectors

One recent development attacks this problem head-on: the quick-connect devices that attach shafts to heads. This has been most heavily publicized by Club-Conex' new product, the Faz-Fit (photo). You can purchase a shaft tip connector (which looks like a ferrule; you epoxy the shaft into it) or a head hosel connector (it epoxies into the hosel bore as a shaft would). Then you use a wrench to connect them together with a screw thread. A hex keyway allows six positions, and prevents the shaft from rotating in the hosel.

How does this deal with the combinatoric problem? If we look back at the brute-force solution to the problem of 180 different heads and 360 different shafts, we need to stock over 10,000 test clubs. But if we buy one of each of the 180 heads and one of each of the 360 shafts, we can equip each head and shaft with a connector -- and we have all the combinations ready to be tried out, one at a time. That's still too many -- but we have made a major inroad in the problem.

The Faz-Fit is the connector that is currently most under discussion, but there are several other developments that attack shaft-head combinatorics in the same way:
  • Nakashima has been making its heads with a connector for a few years now. They supply their dealers with the shaft-tip connectors, so that only one Nakashima test head of each spec need be stocked.
  • My good friend Charlie Badami has been using a quick-setting non-epoxy adhesive for all his clubmaking, but especially for fitting. The 3M acrylic adhesive DP-810 is more expensive than epoxy, but it cures strong enough to hit with in a half hour. This may not be fast enough for trial-and-error fitting, but it is plenty good for measurement-to-specs fitting; that is, if you can deduce the right components from measurements of the golfer's swing, you can build up a test club while the customer waits.
  • Some OEMs are introducing head-shaft connectors as part of driver "packages" of a head and several shafts. I really don't consider this part of the custom fitting trend I'm discussing here for a couple of reasons:
    • The OEM connectors are not compatible with other independent connectors, like the Faz-Fit.
    • Initially, they are being made available not to the dealer (to facilitate custom fitting) but to the customer (who is now "allowed" to spend more for the driver because he is buying a few shafts).
 

Adjustable components

I'm not talking about the hokey "traveling iron" whose loft can be locked with a wrench. Rather, I'm hoping that some other important specs can be made tool-adjustable by the clubfitter.

For instance, consider head weight and the placement of the center of gravity. It should be possible to produce a head (or a series of heads with different lofts) where a weight slug can be positioned inside the head to control the total head weight and the CG position. If it is sufficiently adjustable, then it can be used to greatly decrease the number of driver heads needed for fitting.

But that sort of thing would also depend on science...
 

Science: needed studies

In order to take advantage of adjustable components, we need some assurance that certain properties of the club have predictable effects that are at least somewhat independent of other properties. For instance, it is reasonable to believe that the best loft for one head weight is the same as the best loft for another head weight. But we don't have the controlled studies to support that this reasonable belief is actually true. And we need to know it is true if we are to get by with a single test head with adjustable weight, draw a conclusion about weight, and move on to other specs.

Here are some studies that need to be done in order to be able to trust the results of fitting using the sort of adjustable components described above.
  1. The effect of CG placement on launch parameters. In particular, we not only need to know the effect, but whether the effect is consistent from golfer to golfer, and independent of other specifications. (Actually, it doesn't have to be completely independent, but we need to know the relationship very predictably.)
  2. The effect of shaft flex profile on trajectory and feel. Tom Wishon has done some work to relate flex profile to the golfer being fitted. But a more fundamental piece of information is how a change in flex profile affects the launch parameters, or affects what the golfer feels.

I'm sure there are other important studies that are worth doing. But some will be very difficult to do, and to find definitive answers in the data. Note that the studies I suggest above relate a physical parameter to a physical result. They do not try to relate a golfer's characteristics to a golf club specification. Yes, that would be an extremely valuable result for a clubfitter to have. However:
  • It is subjective experimentation. Professionals in experiment design know that human tests require a lot more data to get reliable results, those results are much harder to distinguish, and the variances in the data limit its assured applicability to any specific golfer. That's why clubfitting is as much art as science, and it is likely to remain so.
  • I have tried to focus on determining how golf club specifications interact with results, not with golfers. My goal is to reduce the number of test club combinations that need to be inventoried. For instance, if we can separate the effect of CG vertical placement from the effect of total clubhead weight, then we can test for each effect separately when fitting a golfer. Then we could do a test for total weight and another test for CG placement; after those tests, we might choose the ideal head for the golfer from a model we don't even have in stock -- with some confidence it will be right.

Instruments and standards

Two major areas where improvements can encourage custom clubfitting are:
A few examples:
 

Launch monitors

This is an obvious one. In the past few years, the reliability of launch monitor readings has increased to the point that they are useful -- nearly essential -- tools for clubfitting. Now the prices have to come down, without hurting reliability. I believe there is room for this to happen, riding on the coattails of some much larger-scale digital electronics trends.

Launch monitors today are based on two different kinds of measurements: doppler radar and cameras. The doppler radar is less expensive today, but camera-based launch monitors are potentially more versatile. We can expect to see meaningful price decreases in top-of-the-line camera-based launch monitors in the next few years. Some of the progress that will enable this will be due to:
  • Improvements in image processing. There have been considerable strides recently in computer interpretation of images. That means that the digital processing underlying the camera-based launch monitor is more capable. One manifestation of this is how the ball must be marked for a camera-based launch monitor to understand things like spin. Until very recently, the ball had to have a prominent stripe that must be aligned with the camera before it is struck. AboutGolf, a manufacturer of launch monitors, is in the process of introducing a new model called "3trak" that allows a much more free-form marking of the ball. The thing that makes it possible is the enhanced ability to distinguish which mark is which from the image of the ball. The advantage is not just easier ball placement. It also allows the measurement of sidespin as well as backspin, which AboutGolf advertises as "3D tracking". We can expect to see more of this in the future.
  • Anybody who has watched the digital camera market over the past decade has observed a figurative avalanche of increased resolution, burgeoning feature sets, and dropping prices. And, as the digital camera moves down the learning curve propelled by mass consumer markets, camera-based launch monitors can and will reap the benefits. Improvements (and falling prices) in lenses and in sensor arrays can be adopted almost verbatim in launch monitors. Clubfitting tools like launch monitors represent much too small a market to ever accomplish that on their own, but should be able to piggyback on the digital camera's learning curve.

New swing-measuring instruments

 The same things that drive the progress in launch monitors -- less expensive digital camera components and more capable image processing -- will make possible new computer-based instruments to measure your swing. This is likely to start as competition for advanced features in camera/computer based golf instruction systems, exemplified by the cSwing display on the right. Today many higher-tech golf schools have systems that video-record your swing on a computer and allow you -- or, more often, your instructor -- to step through the swing. This is generally a slo-mo or stop-action swing analysis, often side-by-side with an ideal or a pro's swing for comparison.

But the techology progress will allow differences from today's systems, not just in degree but in kind. A few things we might expect to see:
  • More cameras. More angles from which to view.
  • Combined with enhanced image processing, multiple cameras might allow viewing from almost any angle. It would deduce the 3-dimensional object's boundaries from images on three or more cameras, and synthesize a virtual camera view from any observer's angle.
  • Automatic swing analysis. Current systems require manual selection of critical points in the swing. But enhanced image processing might be able to identify the same critical points automatically. I'm talking about points like:
    • Beginning of the backswing.
    • Beginning of wrist cock.
    • Transition.
    • Beginning of release.
    • Impact.
    • Left elbow begins to bend.
    • Follow-through.
    By identifying these points in the swing, the system could match the subject's swing against an ideal swing of any speed, and critique the differences.
    Note that it may be necessary in early systems to identify key points like shoulders, elbows, hands, clubhead, etc. Jorgensen did this with reflective tape in his pioneering work modeling the golf swing, and these systems will probably start that way. But they should outgrow it fairly quickly as image processing continues to improve. (Some advanced digital cameras already have face recognition software. That does not appear much harder than identifying body parts in a picture known to contain a single golfer swinging a club.)
  • Measurement of swing characteristics. If it is feasible to do automatic recognition of those critical points of the swing, then it isn't a big jump to an instrument that can measure swing characteristics that are useful to a clubfitter. For instance, characterization of the release (early? late? aggressive?) is an important issue in shaft flex fitting. It would not be hard to add that to a program that was already capable of picking the swing apart as described above. Other fitting-related parameters that might be measured by an image-processing system include:
    • Swing plane and posture (related to one another and to proper club length).
    • Acceleration.
    • Shaft bend during the swing (it would take considerable resolution, and possibly a "virtual camera" pointed perpendicular to the swing plane).
    • Both angle of attack and wrist cock at impact.
 

Shaft bend during the swing

Consider the demise of TrueTemper's ShaftLab, and whether something else might replace it in the near term. ShaftLab filled an important need in both clubfitting and research, but has been withdrawn by the manufacturer. The most likely reasons for its demise are:
  1. Cost: until its final year or so, ShaftLab carried a price in excess of $10,000.
  2. Convenience: the club was tethered by an electrical cable to the computer.
  3. Interchangeability: only the four clubs supplied with ShaftLab could be used.
Let's assume for a moment that an instrument with ShaftLab's capabilities but not its drawbacks would be a success. How could we use current or near-future technology to build such a machine, at substantially lower cost than ShaftLab? There are several issues that need to be dealt with, and at low cost:
  • Detecting shaft bend:
    • ShaftLab did this with strain gauges, which measure the actual bend directly. Unfortunately, strain gauges require a lot of work to attach to the club, so interchangeability becomes a big issue.
    • Accelerometers. Acceleration is not bend. In order to get a good estimate of bend from acceleration, we probably need at least two accelerometers at very different positions along the shaft. For a 2-dimensional measurement (both lead-lag and heel-toe bend), you probably need four accelerometers.
    • Angle detectors. Several companies (e.g., Wixey) make a device that detects the angle at which it is positioned. Let us assume for the moment that (a) the sensor itself (minus the display) can be made very small, and (b) its response time is in the sub-millisecond range, so it can measure angle dynamically enough for a swing. (I have no idea whether these assumptions are true; if not, forget about using angle detectors for dynamic shaft bend.) A shaft bend of 1" creates an angle difference of about 2° between shaft and tip. The Wixey can measure angle to 0.1°, which corresponds to a tip deflection of 1/20", which is certainly good enough for most purposes. Of course, bend is an angle difference; you would need a device near the butt and another near the tip to convert angle to bend. As with accelerometers, you would need four sensors for a 2-dimensional bend measurement.
    • Photographic. A very small camera might attack the problem by sighting down the shaft and recording bend based on the view. This solution, if feasible, could use the learning curve for digital cameras and image processing.
    • Mechanical linkage. OK, so strain gauges need to be permanently applied, eliminating interchangeability. But maybe some kind of linkage extending down inside the shaft can measure the bend mechanically. I have in mind something like a 10"-12" wand, embedded in a strain gauge or load cell at its top (or base), and wedged into the shaft wall at its bottom (or tip). Any bending of the shaft over the length of the wand would move the tip of the wand, which could be detected by the load cell at the wand's base.
  • Connection from the club to the computer. A few ways this might be attacked:
    • A wireless LAN, probably based on Bluetooth technology. WiFi is also a possibility, but probably requires too much power and space -- and its extra range isn't really needed.
    • Store readings in the club, and upload them to the computer via USB connector when not swinging. This is probably too inconvenient.
  • Interchangeability: Any of the above strategies allows the use of any club, except for strain gauges. But there is a challenging calibration issue as the sensors are moved from club to club. Any such instrument would have to be mounted or installed in a carefully controlled position, both rotationally and along the shaft.

Note that a few products have been around for a while that purport to do something like this, and neither has gained even the acceptance that ShaftLab did. SmartSwing's Intelligent Club is no longer offered; it was an expensive training aid, and was never really sold as a clubfitting instrument. (It didn't claim to measure shaft bend, either.) The FitChip suffers from the misconception that a single accelerometer can measure bend. It can't.
 

Shaft flex instruments

So far, we have been talking about instruments to measure the golfer's swing, probably the most important part of clubfitting. But custom clubs also involve club making, which calls for different kinds of instruments. These are instruments to measure the components and the club itself. Examples include:
  • Swingweight scales.
  • Moment-of-inertia meters (pendulums and the new SpeedMatch) to allow MOI matching.
  • Measurement of shaft flex.
Let's look at the latter. For over a decade, shaft flex has been measured by frequency. This is a very practical method, and clubmakers have a lot of experience with it. One reason it is so popular is the availability of the instrumentation at a reasonable price: $300-600. Other ways to measure flex are either inconvenient (a manual flex board) or cost well over $1000 (digital flex boards like the FlexMaster). But they definitely have their devotees, and deservedly so. Recently, several instruments have been introduced in a price range that is competitive with frequency meters, and I expect the trend to continue.

One reason for the trend is the same reason as the upcoming cost reductions for launch monitor; the underlying technology is "moving down the learning curve" with a high-volume product. The expensive component of a digital shaft flex meter is the load cell and related electronics (including the digital display). By itself, this costs as much or more than a complete frequency meter. But the same components are part of digital scales, which are selling by the millions and thus dropping in price dramatically.

The picture shows the essential electronics for a shaft flex meter, which I have incorporated into my own NeuFinder 4 that I use for profiling and matching shafts. I "scavenged" the entire assembly from a $35 digital shipping scale. They work just fine. I think we are going to see more digital flex measurement in the future, as such components become less expensive to the instrument designer.
 

Standards

In his keynote address, Wishon said that standards for clubmaking are unlikely to be adopted. He correctly identified the existing entrenched manufacturers as the culprits, but I don't think he quite got the reasoning. He said that each manufacturer would only accept the standard if it were the "standard" the manufacturer already uses; since these differ from manufacturer to manufacturer, there was no hope of a majority agreeing.

I believe it is more insidious than that. They are opposed to a standard -- period! They don't have to come out and say so; they can stick to the argument, "It's not my way, so it will cost me to change," and appear reasonable. But they really don't want an industry standard to be adopted, even if it is their way.

It's all about "account control". (That's an IBM term, and I'll get back to IBM shortly.) The last thing the OEMs want is for the golfer (their customer) to have an independent, impartial advisor on golf club fitting or purchases. If the customer can go to an independent clubfitter for a reshaft (and, while he's there, hear an unbiased evaluation of those expensive OEM clubs), then the OEM has lost control of that customer account. So OEMs are becoming more skilled at building and selling clubs that must be repaired (e.g.- reshafted) at the factory. Special bushings, nonstandard tip diameters -- this all adds to the difficulty of independent reshafting, and tightens the OEM's account control associated with each club sold.

I promised I'd get back to IBM. That's how I recognized this attitude towards standards. In the mid-1970s, I was on several national and international standards groups on the subject of computer communication standards. At the time, IBM just about owned the computer market; they sold more computers (in dollars) than the next six computer manufacturers combined. And they had SNA, a set of software and protocols that allowed IBM computers to talk to other IBM computers, but not to other manufacturers' computers. If the standards effort were successful, there would be an international standard that any computer manufacturer could implement, and it would allow connectivity with any other computer that met the standard. Such a standard would threaten IBM's market monopoly on computer-to-computer communication, and that monopoly was an important part of their account control strategy. They attended all those standards meetings -- as did the other manufacturers. But IBM's role, if you watched them closely, was to try to throw monkey wrenches into the standards process -- to block the adoption of any standard.

I believe the OEMs are doing the same thing with club measurement standards.

The rest of it

OK, so what about the rest of it? Are there going to be technology advances in the next five years that have nothing to do with custom fitting? Maybe so, but they won't be as dramatic as we saw in the 1990s. Here's my cut at what is going to happen with clubheads, shafts, and balls.
 

Heads

I don't think we'll see all that much improvement in irons. Much of the reason I say that is there is no trend of improvement to extrapolate. Iron technology hasn't improved much since 1990. As the table above showed, all the distance gained over that time has not been due to technology, but to marketing: the "loft wars".

So let's look to drivers for improvement. Yes, I know that the USGA is working hard to limit improvements in drivers. But here are a few things that could still be attacked.

The first two are somewhat fitting-related, in that not all golfers will benefit -- just those with certain swing characteristics. The first is dependent for improvement on high clubhead speed, and the other on low clubhead speed.

Lowering the center of gravity of the clubhead could pay dividends for the golfer with more clubhead speed. That's because the more above the CG is impact with the ball, the lower the backspin. (That's because of vertical gear effect.) Golfers with high clubhead speed get more distance from less spin that the nominal optimum loft would give, and the way to reduce spin without losing launch angle is for impact to be higher above the CG. And the thing you can do with the club to make this happen is to lower the CG without reducing the face height. (In other words, it won't work to lower the CG by making a shallow-face driver -- the easiest way.) What sort of technology can lower the CG?
  • Cleveland's Hi-Bore does it with head shape. The crown is concave rather than the usual convex, so all the mass associated with the crown is lower in the club.
  • Callaway (and occasionally others) do it with materials. In particular, they make the crown a lighter material, a carbon-fiber composite.
  • Other things we may eventually see: making the crown lighter with internal bracing, perhaps even lighter materials for the crown, and -- the ultimate step -- elimination of the crown altogether. (I have seen an off-brand club like this; it looks funny but it might work.)
Raising the loft, on the other hand, is a boon to golfers with lower clubhead speeds. If your clubhead speed is low enough (Tom Wishon feels this is around 100mph), then spin is your friend not your enemy. But you probably do need more launch angle than your current driver may provide. This can be accomplished by increasing the loft.

The biggest negative to high-loft drivers is a sales issue. Real men don't want to admit -- not even to themselves -- that they need a high loft. There doesn't seem to be any problem selling 14° drivers in ladies' clubs. But lots of men need that much loft and more, and refuse to get it. While there is no technological challenge to make this happen, entrenched attitudes will greatly slow down its adoption.

A bigger sweet spot. Before you decide I'm out of my mind to suggest this, yes I have thought about:
  • "The sweet spot is a point; how can it get bigger?" A lot of people hold to this semantic nonsense, which is not productive. The sweet spot is the place[s] on the face that give maximum distance when you hit it there. Engineers know that you are always limited by tolerances, and that includes tolerance in how you measure the maximum distance. Assuming you can reliably measure it to, say, one yard, the sweet spot is not a single point, but a locus of points that give within one yard of the maximum distance you measured. So it is perfectly correct to say that a more forgiving head has a bigger sweet spot. A bigger area of the face can be used to hit within one yard of the maximum distance.
  • The USGA has restricted the maximum MOI of the clubhead. True enough, but...
There are rather few clubheads today that are pushing MOI limits in the new rules. So there is room for improvement.

But wait! The sweet spot is no longer just an MOI issue. With the USGA allowing a limited spring effect, COR (coefficient of restitution) is also an issue. The maximum COR of 0.83 is taken at the center of the clubface. In general, COR (and thus distance) falls off as impact moves from the center of the face. Keeping the COR high over more of the clubface is now just as much a sweet spot issue as MOI is. And we should see engineering effort addressing that problem over the next few years.
 

Shafts

Shafts may or may not see advances in the near future. The "may not" is because the basic materials for advanced shafts, carbon fibers and resins, are in short supply and therefore high in price. And the trends in these raw materials do not suggest any easing of costs in the next few years. So I expect much of the effort will go into advertising (to justify the higher prices that will be necessitated by higher costs) and perhaps some success at alternative materials.

The materials search may be a double-edged sword. The thing that is visible in the short term is better performance in carbon fibers. This is technological progress, but will only raise prices -- we are still talking about carbon (which is increasing in cost), plus manufacturing processes that will be even higher than current graphite fibers at least for a while.

The progress in materials has been taking place at the molecular structure level for carbon structures. The most prominent of these is nanotubes, microscopic (molecular level) long-chain fibers that are much stronger than ordinary carbon fibers. They are already incorporated in a few high-end shafts. But that isn't very significant; so far they are more for advertising value than structural value. In order to achieve their potential, the structural element of the shaft must be the nanotubes. After all, shafts are already strong enough; the point of improved fibers (e.g.- nanotubes) is that you can use less fiber to achieve the same strength. Less material means lower weight, so the payoff would be even lighter weight shafts, with the same strength we make today. In order to make a lighter composite, the use of nanotubes would have to enable a significant reduction of conventional fibers -- and perhaps even less resin (since the smaller nanofibers are bearing the load, and there's less of them for the resin to bind together).

Here are a few issues that will be worked in the next few years -- but I don't know whether they will be worked successfully:
  • Economical production of nanotubes. The problems here are both raw materials and manufacturing processes.
  • Economical production of shafts whose major load-bearing material is nanotubes.
  • Health issues associated with nanotubes. In the last couple of weeks, there have been several articles reporting studies showing that carbon nanotubes may have health-related problems akin to those of asbestos. Injected nanotubes have induced the same diseases in mice that asbestos does. No studies yet to determine if inhaled nanotubes have the same effect as asbestos. But, if so, then professional clubmakers would definitely face a hazard when trimming shafts made of nanotubes.
An alternative to carbon nanotubes is graphene -- nano-level carbon sheets. These nano-particles are almost as strong as nanotubes, considerably cheaper, and less likely to cause health problems. Current investigation and development of graphene-resin composites does not include golf shafts -- yet. But, if nanotubes continue to unearth new problems as fast as old ones are solved, we may very well see research on graphene shafts.

One thing that I do not expect to change in a big way over the next five years is shaft spine. The last five years have seen a number of companies get religion on the need for low spines. Other companies have declined to, on the grounds that it is more costly, and customers are not willing to spend the money on spine-free quality. Both attitudes are correct; some customers will spend the extra money, and others will not. So, unless the Rules bodies (USGA and R&A) decide to legislate tolerances on shaft asymmetry, I think the market is relatively stable in that regard. (And I don't see any enthusiasm in the Rules bodies to change this.)
 

Golf balls

Golf balls have evolved enormously over the past two decades. Performance is way up, especially if you measure performance as driving distance. And most of the world's golfers measure performance exactly that way. And so does the USGA when enforcing its Rules. Let's look briefly at what the USGA controls in its ball testing.
  • They limit the ball velocity as the ball comes off the clubface. This is a "standard" clubface, presumably with the maximum 0.83 COR.
  • They limit the total distance. But, reading between the lines, this distance is computed from limited measurement. They measure the ball's trajectory for 70 feet of flight to get a handle on the aerodynamics, then they compute the distance.
So let's see what technology might be able to improve, that would not be flagged by the conformance testing. Remember, if it doesn't get through conformance testing, it is not a technological advance in golf -- nobody will ever use it for legal, competitive golf.

Enough is now known about aerodynamics to be able to optimize the lift and drag on a golf ball to give maximum distance for any given set of launch conditions. We also know how to build balls to turn a given set of impact conditions (e.g.- clubhead speed, angle of attack, loft, other clubhead parameters) into good launch conditions. How can we use this techology in ways that don't fail conformance tests?
  1. Ball fitting. So far, I've been talking about club fitting. But, once you've optimized the club for the golfer, you still don't know if you have the best ball for the golfer. Given a swing and a club, there is still an optimum spin, lift, and drag and they vary from golfer to golfer. Fitting a ball to a driver (golfer) and a driver (club) is mostly unexplored, and we can expect to see the exploration start in earnest. This may conceivably beat the conformance tests if the golfer being fitted does not swing identically to the USGA robot. As the impact conditions depart from those of the robot, different ball designs will give optimum flight. And some (many? don't know) of those ball designs will be conforming.
  2. Driver-wedge difference. Suppose we know the best recipe for a golf ball to maximize driving distance for a golfer. Will the golfer necessarily be satisfied with wedge performance? For instance, suppose some Sunday golfer will get the most out of his drive from a "distance rock". Most such balls on the market give no bite coming into greens and no putter feel on the greens. In other words, the best driving ball may be a lousy short-game ball.
    Titleist's biggest contribution with the ProV-1 line is the ability to engineer the driver distance and the wedge spin somewhat independently. I think we will see this continue. Yes, it is good fitting practice. But it may also be an economical imperative for the ball companies, who want to sell premium balls to everybody they can. As the majority of golfers learn that the current "premium balls" will not give the best distance for them, the ball companies will have to come up with new, better-engineered balls (read that as "higher-priced") that give them better performance around the greens.
 

Science

I thought about writing a section on scientific studies I would like to see done -- things we still need to know about golf equipment. But I decided to punt for now. There's enough involved so that's best done as a separate article. I hope I get to it in the near future.

Notes:
This is hardly the first try I've taken at technology forecasting. From the late 1970s through the early 1990s, one of my responsibilities at Bell Labs was to do 5-year forecasts for various technologies associated with computers and telecommunications. I have written a companion article on techniques and principles used by techonology forecasters, several of which were applied for this forecast.

Last modified -- July 21, 2008