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Golf Equipment Chronicles 2005 (Part 4)

Moment of Inertia Matching & Ireland Bag Surprises

This was a great month for new discoveries tempered by more than the usual hurdles. It all started with a simple project that kept getting more and more complicated. Since Tom Wishon’s new book -- The Search for the Perfect Golf Club -- came out, I’ve been thinking it’s about time to check up on whether Moment of Inertia (MOI) matching golf clubs is destined to replace swing weight matching. Tom has been beating the drum in favor of MOI for a couple of years. Most of the deep thinkers about golf equipment seem to agree that MOI matching golf clubs is scientifically more correct than swing weight matching. What does that mean to a player who is trying to squeeze a little better performance out of his clubs?

I suffered one interruption -- eight days playing some of the best courses in Ireland. That meant I had to pick my traveling bag which is always traumatic but I won’t complain. That’s my job.

Three years ago, I started my own “Search for the Magic Driver.” The Magic Driver is as elusive as the Holy Grail. It’s almost always a false hope to fall in love with a driver at a demo day and order an “identical” club from the factory. No two clubs are ever exactly alike. Hundreds of Chronicles readers confirmed that drivers ordered with “identical” manufacturers’ specifications didn’t feel or play the same as the demo. Why can’t we figure out how to make two clubs match?

I reported on Tour professionals who find their own magic drivers by testing dozens, sometimes hundreds of drivers (provided free of course) to find THE ONE. No amateurs have that opportunity. At the Golf Lab, we employ three different launch monitors to try to detect performance differences to narrow the search. “Always buy the demo” is our mantra. Random trial and error isn’t a scientific method.

We’re good at building drivers that almost match the performance of our test clubs. We developed methods to measure loft and face angles, add weight to heads and compare shaft performance through zone frequency profiling. We verify ball speed, launch angel and spin rates with launch monitor testing. The ultimate proof is finding your ball in the fairway a few steps ahead of your normal spot. But we’re tormented by that nagging thought that there must be a better way to match “feel.” Is MOI matching the “Next Big Thing” in clubmaking?

What About Magic Irons?

Irons present a different problem than drivers. They come in a set. The idea behind MOI is that all irons in a set should feel alike. But irons are just as fickle as woods. It’s not unusual to build a custom set, play it one or two days and cycle it back to eBay. In the last year, I built myself at least ten sets of custom irons with all sorts of different heads, shafts and grips. Each set was built to a version of what I thought was my specification at the time. Most of those sets are on the shelf today, disappointing for one reason or another. Why can’t I do a better job of building sets for myself?

There are a couple of individual clubs that I keep remembering fondly. One is a five iron from a set of “Joe Blades” shafted with Fujikura VP 90s. I’ve hit some shots with that club that gave me Goosebumps. I remember knockdown shots into the wind over the water that went for birdies. It’s spooky how you remember a “favorite club” that performed time after time even if the set is out of play.

There are two other irons that seemed unusually good: a seven and eight out of a set of Ping Eye 3+ heads shafted with Aerotech 80 gram graphite shafts. When I swing those they simply feel perfect. I don’t think I ever miss a shot with them.

But what about the rest of the set? Why isn’t every club just as good? Why can’t we match a “magic” iron and produce a complete set of perfectly matched irons? That’s exactly what MOI matching is designed to do. But does MOI matching work? What is the truth?

State of the Art in Matching Irons

For over 80 years, the principal method for matching golf clubs has been by swingweight. Swing weight might be an imperfect measurement but it is convenient and understandable. It was invented in the 1920s by Robert Adams. The Kenneth Smith Company acquired the rights to the Adams system in the 1940s. The Kenneth Smith swing weight scale, virtually unchanged, became the modern standard and has been copied in many different forms over the years.

Swing weight scales are simple devices. They lever the grip of a club under a stop and balance the combined weight of the head and shaft that extends past a 14” fulcrum. The result is expressed in a letter-number value. “Standard” swingweight for modern golf clubs is D-0 with a normal range of five points in either direction. I have discussed nuances of swingweight in previous articles so instead of repeating that information here, have a look at www.calgolftech.com if you need a refresher.

Here are some facts about why relying on swingweights for matching golf clubs is unreliable. First, if you measure swingweight on three different scales, you will get three different values. That’s the first eye opener. The delta might not be huge, but it’s common for two to scales measure swing weights two points apart. At the Golf Lab, we identified our “benchmark” scale -- defaulting to the method of choosing the most expensive one to trust. As usual, price did not equal quality.

Second, it’s not a sure thing that a player can detect a small difference in swingweight. When Bob and I worked the SST Tour Van at the AT&T a couple of years ago, the consensus of the clubmakers who travel with the PGA Tour from week to week was that the only player who could feel a single swingweight point difference was Jose Maria Olazabal. So, start with scales that give different values and players who can’t tell the difference anyway, it makes you wonder why players focus on swingweight matching as a sign of quality in golf clubs.

Finally, swingweight is a “static” measurement. It is intended to represent the “heft’ or “head feel” of a club in a player’s hands. Would it not be better to try to measure feel in golf clubs by reproducing the dynamic action of a player’s swing?

Moment of Inertia (MOI) Matching

MOI matching golf clubs starts with attempting to measure the resistance of a club to being placed in motion. The theory is that if a set of golf clubs can be built so that it takes the same amount of force to swing each club, a player will experience more consistent shot making. Swing weight matching attempts to make clubs feel alike when you grip them and “waggle.” MOI matching attempts to create a set of clubs that feel the same when you swing.

MOI matching is driven by mathematics and software. Without computers and inexpensive electronics, MOI matching is impractical.

MOI Matching Methodology

The equipment to find the MOI of a set of irons is relatively simple, as is the process. However, it is significantly more complex than measuring and adjusting swing weight. It takes an experienced clubmaker over an hour to MOI match a set of irons. The first step is to measure and weigh each club and find the balance point. This data is saved in a chart. Then each club is attached to a swivel at the grip and oscillated vertically. An electric eye records the oscillations and returns a “period value” which is the average duration of a single oscillation. The period value is expressed in seconds, to four levels of decimal precision. That value is also saved in the chart. Once all of the data is recorded in the MOI software, you hit the “calculate” button and “voila” the swing weight and MOI of each club is displayed. The MOI value is expressed in a range between 2700 and 2950 for irons. The presumption is that one of those MOI values should be “perfect” for your swing.

Finding the best MOI value for each player rests on a controversial assumption. That assumption is that you certainly must have a favorite club in your set and your goal should be to make every other club in the set match that one. This assumption is probably not always correct. But if you do have a favorite club in your set, you can enter that club and its MOI value in a window, hit “calculate” one more time and the program will tell you how much weight you need to add or subtract from every other club in your set to create a set that’s perfectly MOI matched. Then you get out your gram scale and lead tape.

You Never Know Until You Try

In researching this article, I MOI matched several of my own sets of irons. Clubmakers should plan on spending a few days working on their own sets before offering MOI matching services to customers. Here’s an overview of some of my findings:

Joe Blades, Vista Pro 90 Shafts

This set turned out very conventional. It is a set that has a “favorite club.” It’s that same five iron that’s saved my life on many occasions. When I entered the calculated value for the 5 iron MOI, adjustments to the rest of the set were displayed. The program wanted me to grind a couple of grams off of my three iron and then add progressive weight to the rest of the clubs in the set. These recommendations ranged from adding 1.4 grams to my four iron up to nine grams to my nine iron. For any readers who are interested in the underlying charts, you can find them posted on www.calgolftech.com. This result was consistent with the most common result in an MOI matched set -- increasing swing weight progression through the short irons.

I decided to make the Joe Blades my serious test set. I recognize the problems with player testing and all of the inconsistencies related to relying on human beings. This is a tournament-proven set that I played for a full season but for some reason went in the closet. I followed the MOI Analysis program recommendations for adding weight. The resulting set, described in more familiar swing weight terms showed a gradual swingweight increase from D-3 to D-7. The MOI value of 2850 was my “favorite club” sweet spot. Every club in the set was within ten MOI points of the “magic” five iron after adjustment.

In two lengthy range sessions, I imagined that the clubs felt more consistent. What does that mean? I was looking for a better shot dispersion pattern, better distance control and better tempo. The problem with human beings testing golf clubs is that if they want one club to perform better they can usually that happen -- even if subconsciously. Another problem with human beings is that they expect miracles. They want to take a new club to the range and hit every shot perfect. It never works out that way. You should never give up on new clubs until you’ve given them a second chance.

I worked out a little drill. Since I was looking for consistency, I figured that if I could change from club to club on the range without clunking the first shot or two with the new club, it would be a good sign. After a substantial “get acquainted period” I had the feeling that as I moved from club to club, the adjustment was less with my MOI matched Joe Blades. If that’s true, it would be very good on the golf course where you move from club to club every shot.

The Joe Blades are going to require some tweaking. Nine extra grams of weight on the nine iron and six on the pitching wedge were definitely noticeable. I began to think that the short irons felt too heavy. I’ll trim 1/4” off of the short irons and a bit more from the three and four iron. This should bring the set into a little more controllable length at heavier weights. Then, I will replace the grips with midsize. When I built the Joe Blades a couple of years ago, I was into my small grip period. Now I think a bigger grip lets me square up the face a little easier.

In researching this article, I contacted 30 of the 52 clubmakers listed on the Wishon Golf Technology website as “MOI Certified.” Those who had enough experience with customers to generalize their results reported subtle improvements. Some reported more consistency, some a slightly different trajectory, a couple more distance. Some clubmakers had customers that posted lower scores. There were no miracles but also no complaints.

You’ll have to wait a month for the next chapter of this story. I’m going to put the Joe Blades back in the bag for the “Mornings at the Muni.” They deserve 72 holes of opportunity to earn their way back out of the closet. I know it’s a good set. It would be a great test of MOI matching if the Joe Blades get back in the tournament bag. How else would we know that MOI matching delivers on the promise?

MacGregor 565 Blades with Aerotech 80 Gram Shafts

These irons are newcomers. The Macs made the traveling bag to Ireland at the last minute. They made the trip because they performed well during one of my last-minute mornings at the Muni. When I made the measurements and calculated the results, (based on my favorite club being the 6 iron because I made two birdies in Ireland with it) the set came out almost perfectly MOI matched. There wasn’t a club that required more than a gram of weight to bring it into the magic 2850 range. I added the lead tape out of superstition and resolved to put the Macs into my steady rotation.

The measured swing weights showed a gradual increase from D-3 to D-8. The static weight of the Macs was about six grams lighter than the Joe Blades across the board. That difference was totally attributable to the difference in shaft weight. Here’s another possible result: you might get a perfectly MOI matched set by accident.

Ping Eye 3+ blades with Aerotech 80 Gram Shafts

This set was the big surprise. It was the one that made me start thinking that the “favorite club” method of MOI matching not reliable. It turns out that there are two clubs in that set that I love. The seven iron and the eight iron have both performed great. I made the measurements and calculated the MOI. It turned out that the seven and eight irons were very different clubs. The eight iron registered an MOI value of 2814 while the seven iron was 2865. The consensus of most experienced MOI clubmakers is that an acceptable range for MOI matching is roughly 20 points or 1%. These two irons were well out of that range.

You notice anomalies when you collect the data for the MOI charts that might not show up in swing weight measurement. When the weights and balance points don’t demonstrate a regular progression, it should raise a red flag. Here’s the rub: I didn’t know that the eight iron was much lighter than the seven iron. The swing weight scale said that they matched. The strange result had to do with a weird weight distribution in the two shafts. If I were to base the MOI adjustments on the eight iron as my “favorite club” I would have completely ruined the set by grinding too much weight off of the other clubs. My conclusion is that trusting a player’s “feel” to determine his favorite club is unreliable, at best. MOI matching might turn up a club that is simply out of specification.

In a way, you can think of MOI matching a set of irons as an insurance policy. You might think they’re great. They might not be. You’ll find that out.

An Alternative Method for Finding a Favorite Club

At the Golf Lab, we trust launch monitor data. We also trust impact labels. Our fitting methodology starts with static measurements to get preliminary club length. We then go to dynamic testing to set the lie angle. We confirm club length with impact labels and test clubs. We work on flex with the Achiever and Max Out launch monitors, looking for performance indicators including swing speed, ball speed, carry distance and consistency. Finally, we test for optimal swing weight. Most commercial irons are delivered at a D-0 or D-1 swing weight to make things simple for the manufacturers. In launch monitor testing, we very rarely find that D-1 swing weight delivers the best performance. In our fitting sequence, we progress through a series of test clubs, correct length, flex and lie angle and increasing swing weight. We usually find that a swing weight in the D-4 to D-5 range, at least in the short irons, delivers the best results. When the swing weight gets too heavy, the performance indicators begin to decline. Launch monitor testing reveals that point.

This process is somewhat painstaking; however it is a much more reliable method for finding your “favorite club” than trying to remember a club out of your set that might have produced a few good shots in the past. My own experience with my Ping Eye 3+ set proves that a player can have a hard time distinguishing performance differences between very different clubs.

Since I’m discussing “standards” that don’t work for most players, if you haven’t checked your length specification recently, buy a copy of Tom’s book and check out his chapter on club length. Manufacturers have been lengthening their standard lengths lately in a quest for more distance. If you are playing irons based on a 38” five iron and you’re not over six feet tall, there’s a good chance your clubs are too long. Confirming club length is simple. All you need to do is hit your irons with impact tape on the face and do the same with irons a bit shorter. Compare the pattern. You’ll probably find that your center strike pattern is better with shorter clubs. We’re finding that a higher percentage of our customers are going with shorter lengths. And you don’t lose distance either. If you’re looking for a breakthrough, you should test shorter length and heavier swingweights.

Measure with a Micrometer; Mark with a Chalk; Cut with a Chainsaw

My grandfather was a carpenter. He trained me to think about every job as a series of precise operations. If any operation was conducted haphazardly, the final result would surely be suspect.

As I worked on sorting out the mysteries of MOI, I encountered several problems that make me wonder if we’re playing with a full deck.

The first issue is relying on swing weight. We have five swing weight scales at the Golf Lab. They range from the early classic Kenneth Smith, through the range of Golfsmith offerings up to the top of the line Golfworks premium scale. Measure a set of clubs on any of the scales and your values will be different. Not too much, but a couple of points difference club to club is not uncommon. That could be a four or five gram error. There is no way that I know to calibrate a swing weight scale. The best you can do is to keep a test club that you trust around the shop to reveal the difference between scales. You simply have to choose one scale that you trust and go with it. As usual in the golf business, but most expensive was not the best. Here’s the point: if you think that you know your “favorite” swing weight, try a different scale and be ready for a surprise.

The MOI software calculates swing weight based on mathematical formulas. That calculation gives a different value than any value you will measure on a scale. When I was working through the MOI software, checking the calculated versus physical swing weight values, I was frankly shocked to see deltas as much as three or four swing weight points difference in the same club, depending on the method of calculation or measurement. In the end, I tend to trust the calculated value in the MOI program, despite my distrust for software swing weight calculators in general. If you want to see for yourself, I have included measured and calculated swing weights in the MOI charts posted on the www.calgolftech.com website.

The second issue is measuring club length. In talking with Mondher Lattiri from Golfmechanix, the manufacturer of the MOI system and software marketed by Tom Wishon Golf Technology, he was adamant that club length measurement was crucial for making the MOI software work. The recommended method is to measure each iron in the playing position -- the correct lie angle -- from the middle of the sole to the top of the grip cap. This method is approximated by clubmakers who slide a yardstick behind the heel of an iron to get the length- a notoriously inaccurate technique. The Golfmechanix method is to utilize their own device called the Auditor which registers the club at a known lie angle and rests the shaft in a ruler. I tested the Golfmechanix method by utilizing a top of the line Golfsmith lie angle gauge and a ruler.

That method of measuring club length is different from the method we employ at the Golf Lab. We have standardized on the Mitchell Golf production equipment which is a common standard in professional club shops in the US. The Mitchell system employs an aluminum pad with a couple of pegs that register the club head and an aluminum ruler that handles the length measurement. The Mitchell system does not measure from the midpoint of the sole. Rather it chooses a point a few clicks in from the hosel -- arbitrary and proprietary.

When it became apparent that Mondher and I were talking about apples and oranges with respect to measuring club length, I put in a call to Mike Stevens, technical guru at Mitchell Golf. Mike admitted that when Mitchell developed their system they were looking for speed and “repeatability.” He acknowledged that the Mitchell system measures up to 1/2” shorter than the “traditional” Golfmechanix system.

So, for all of you who think you know what club length you’re playing, here’s the bottom line: Depending on the methodology employed, there might be a 1/2” no man’s land in measuring golf clubs. Once again, just like swing weight scales, the only logical way to proceed is to choose the method you’re going to use, standardize on that and go down the road.

Once Again, There Are No Standards

Golf Equipment Chronicles readers have encountered this conundrum many times in the past. We all know that there is no flex standard. Relying on one manufacturer’s “S” to be similar to another manufacturer’s “S” is risky. It was frankly a surprise to me as I peeled the MOI onion that we don’t even have an agreed standard way to measure the length of a golf club.

This finding points out that if you want to pay attention to MOI, you are going to have to find out the method that your clubmaker used to determine his MOI calculations. One clubmaker’s MOI values will be different from another’s unless they used the same method to measure club length. Just like flex and swing weight, MOI values are going to be clubmaker-specific.

MOI and Practical Experience

Once you understand what’s going on with MOI, some of the things that clubmakers have been doing for years -- mainly to accommodate players with an advanced sense of feel begin to make sense. For example, we have been altering the length progression in irons to make them easier to hit. Rather than going with the standard 1/2” progression between long irons, we have cut that to 1/4”. At the other end of the scale, we have also decreased the length progression from the 9 iron through the wedges to 1/4”. Many players have found that they like their wedges to all be the same length. Both of these methods bring MOI closer together. It’s interesting that clubmakers and skilled players have requested these modifications because they just feel better.

Similarly, it is quite common for players to add weight to their wedges. Many Tour players like wedges in the D-5 and up range, even when the rest of their irons might be a more traditional D-1. This is another example of players tinkering with their clubs and a roll of lead tape on the range to experiment with feel.

For players who are interested in experimenting with MOI without going through all the rigmarole of measuring and testing, you could try a much simpler experiment. Assume that your five iron is your favorite club. If it’s a D-1 swing weight, add 2 grams of lead tape to get it up to D-2. If your 5 iron is 38”, make your 4 iron 38.25” and your 3 iron 38.5.” Going the other direction, add lead tape to your six iron to bring it up to D-2.5. Bring your seven iron up to D-3. Continue with the lead tape so that each successive iron measures half a swing weight heavier on the swing weight scale. It will also help to decrease the length progression from your nine iron through your wedges to 1/4”. Your sand wedge should be your heaviest iron club. Make your lob wedge at least a swing weight point lighter. That will give you a set that more or less approaches what a professional clubmaker would get from measuring and tweaking for a couple of hours. If you like the result, you can always take the set to a clubmaker who has the MOI equipment and get the job done precisely.

Future Projects -- Drivers, Fairways and Wedges

Many of the MOI certified clubmakers reported success matching Drivers and fairway metals. I’m anxious to have a close look at my wedges. I’ve got one sand wedge that for some reason is working great -- it’s a bona fide “favorite club.”. Over the next month I’ll have a chance to work on other club categories. The MOI values will be different than irons. Tom Wishon emphasizes that woods and irons should be set to different values due to the much different club lengths. It’s not clear if wedges are yet another category.

Technical Resources

The main proponent of MOI matching is Tom Wishon. There is plenty of technical information on the Wishon Golf Technology Website. www.wishongolf.com. Clubmakers can order the period counter and software to perform their own MOI analysis from WGT.

Golfmechanix.com is the source for sophisticated clubmaking tools and equipment. The website requires you to identify yourself, which is a painless process. Golfmechanix supplies a lot of the clubmaking tools that appear in the Golfsmith catalog. www.golfmechanix.com.

Dave Tutleman is one of the pioneer technical clubmaking gurus. He has published quite a bit about swingweight and MOI analysis. Much of his work was completed in the late ‘90s when the tools and software were not as sophisticated. His work is still enlightening. Find it at www.clubmaker-online.com.

Choosing the “Ireland Bag”

April was a great month for “adventure golf.” I had an invitation to play eight great golf courses in Ireland. I couldn’t face the prospect of eight rounds with the same set of clubs. As usual, I conducted a tryout. I was the only guy on the trip with two sets of irons in the bag. The Nike Blades made the trip with the Mac 565’s. I’m going to do a complete article on game improvement clubs for low handicap players next month. This is bad news for golf snobs. We’re getting fabulous test results with the Macs and Nike Slingshots. If your handicap is under ten and you’re complacently playing forged blades, get ready for a little cognitive dissonance.

The Ireland winners included the Mizuno 21¡ Fli Hi shafted with the Fujikura Banzai. That’s a club you absolutely need on the links courses when the wind is blowing. I think that it will replace my 3 iron in the tournament bag. I made a mistake with my 3 wood. I gave my favorite American Golf Technology 3 wood the ride. On the links courses you absolutely need a very shallow face on your 3 wood to get the ball up off the tight fairways. I didn’t hit a single fairway three wood in eight rounds due to lie issues. Live and learn. The driver that made the trip was a “Tour Issue” Taylor Made 510 TP with a Fuji SIX shaft. It worked out great. For links courses, you need a driver that goes low, lets you choke up a bit and hit “stingers.” Overall, there weren’t too many modifications from my last trip. I covered that one in excruciating detail. You can find that article on the www.calgolftech.com website.

Update on the Total Rehab Project?

I stepped on the scale. 246. Still twenty pounds too much. But then I fell off the wagon for the trip to Ireland. I haven’t had the guts to step back on. That was a tough five weeks. Even tougher is knowing that I’ve probably got ten more weeks before I’m where I want to be. But I made four birdies at Waterville. The tournament season is starting so I’ll start to get some indication if being in better shape brings my index down. I won’t bore you with the details, and I won’t nag but if you’re out of shape your golf game is going to suffer.

I also added “hit 10,000 chip shots” to my list of rehab projects. I can’t stand practicing my short game. But it’s working, I’m about 1,000 into the quota and I’m looking forward to chipping from the fringe instead of taking the chicken’s way out and putting.

If you’re in the Palo Alto area and want to join me for “mornings at the Muni” just give the shop a call so I know you’re coming. Get there at 7 for a cup of coffee. We’ll be on the course by 7:30. Don Diaz makes great omelets.

Leith Anderson is a partner in the Golf Lab in Palo Alto. He will answer all questions related to clubmaking and clubfitting personally. Contact Leith Anderson by email: Leith@calgolftech.com. Cell phone 650-743-2816.