MOI matching myth

[DavidLake]

It has become a popular notion of late that the MOI (moment of inertia), of a golf club is the determining factor when an individual chooses a particular iron from his entire set of clubs as his favorite. The promulgated theory is that the feel of this particular iron (MOI), during the swing is of primary concern to the golfer. Our testing over the course of fifteen years and interviews with hundreds of golfers of all skill levels has shown that MOI has absolutely nothing to do with this determination. The overwhelming determinant that we found as to why an individual selects a particular iron as his favorite is his ability to make consistent solid ball contact.

From our interviewing we found that approximately 98% of all golfers have a favorite iron that they have complete confidence in and can rely upon time after time. Our testing showed that this single iron was in all cases the one where the relationship of the clubhead lie angle to club length came closest to actually fitting that individual golfer. For those golfers with a large wrist-to-floor measurement this club would generally be the #4 or #5 iron, while those with a small wrist-to-floor measurement generally chose the #9 iron or PW. The average golfer whose wrist-to-floor measurement falls somewhere in between generally chose the #7 iron as their favorite. It is interesting to note that the golfers we interviewed did not mention feel, swingweight, MOI, or anything other than their ability to strike the ball consistently in making their decision.

Based upon these interviews and our testing we determined that the only way to build a complete set of “favorite” irons for an individual golfer revolved around the clubhead lie angle to club length relationship. This relationship determines the swing posture and swing plane of the golfer. Our goal was to use the clubhead lie angle and club length to force the golfer into the ideal swing posture and swing plane that maximizes the skeletal, muscle, tendon, and rotating joint functions of the human body to produce the most effective combination of power and control in a golf swing. Although we already knew that this ideal swing posture and swing plane was the same for all golfers, our interviews and testing confirmed this beyond the shadow of a doubt. Our earliest testing showed that there is a direct correlation between the golfer’s wrist-to-floor measurement while standing and the distance from the butt end of the golf club to the ground at impact during the golf swing. Once the distance from the butt end of the golf club to the ground at impact is determined, proper club length is calculated using a trigonometry formula (an imaginary line from the butt end of the golf club to the ground forms one side of a right triangle). By plugging in the ideal clubhead lie angle you can solve for the hypotenuse, or golf club length. This calculation provides correct club length for all golfers regardless of height or arm length and that in combination with the ideal clubhead lie angle produces a complete set of “favorite” irons.

[BC MIST]

It has become a popular notion of late that the MOI (moment of inertia), of a golf club is the determining factor when an individual chooses a particular iron from his entire set of clubs as his favorite. The promulgated theory is that the feel of this particular iron (MOI), during the swing is of primary concern to the golfer. Our testing over the course of fifteen years and interviews with hundreds of golfers of all skill levels has shown that MOI has absolutely nothing to do with this determination. The overwhelming determinant that we found as to why an individual selects a particular iron as his favorite is his ability to make consistent solid ball contact.

From our interviewing we found that approximately 98% of all golfers have a favorite iron that they have complete confidence in and can rely upon time after time. Our testing showed that this single iron was in all cases the one where the relationship of the clubhead lie angle to club length came closest to actually fitting that individual golfer. For those golfers with a large wrist-to-floor measurement this club would generally be the #4 or #5 iron, while those with a small wrist-to-floor measurement generally chose the #9 iron or PW. The average golfer whose wrist-to-floor measurement falls somewhere in between generally chose the #7 iron as their favorite. It is interesting to note that the golfers we interviewed did not mention feel, swingweight, MOI, or anything other than their ability to strike the ball consistently in making their decision.

Based upon these interviews and our testing we determined that the only way to build a complete set of “favorite” irons for an individual golfer revolved around the clubhead lie angle to club length relationship. This relationship determines the swing posture and swing plane of the golfer. Our goal was to use the clubhead lie angle and club length to force the golfer into the ideal swing posture and swing plane that maximizes the skeletal, muscle, tendon, and rotating joint functions of the human body to produce the most effective combination of power and control in a golf swing. Although we already knew that this ideal swing posture and swing plane was the same for all golfers, our interviews and testing confirmed this beyond the shadow of a doubt. Our earliest testing showed that there is a direct correlation between the golfer’s wrist-to-floor measurement while standing and the distance from the butt end of the golf club to the ground at impact during the golf swing. Once the distance from the butt end of the golf club to the ground at impact is determined, proper club length is calculated using a trigonometry formula (an imaginary line from the butt end of the golf club to the ground forms one side of a right triangle). By plugging in the ideal clubhead lie angle you can solve for the hypotenuse, or golf club length. This calculation provides correct club length for all golfers regardless of height or arm length and that in combination with the ideal clubhead lie angle produces a complete set of “favorite” irons.

There is no doubt that the lie angle and club length are two of the most important parameters in satisfactorily fitting a golfer with clubs. As part of the purchase price of any set of clubs in retail operation, I believe that the lie angles specifically must be dynamically checked and adjusted if necessary. However, how many retail operations do this for free, and without being asked?

It is also easier for you to fit and satisfy your customers as all clubs are the same length.

Having said that, what is wrong with MOI matching a set of irons for example, after getting the proper length and lie angle? Would they not all "feel" better? Would they not all then require the same amount of force to swing? Would they not all sqaure up at the same point in the downswing? Are Tom Wishon and Dave Tultleman both wrong when they say that MOI matched clubs are more likely to increase consistency?

Regarding the use of trigonometry to determine proper club length, the idea is great. Would you explain how you do it dynamically, ie., at impact, versus from the address position?

I have only built 3 MOI matched set of clubs, other than my own and the question I asked the golfer was not, "What is your favourite club?" but, "With what club do you hit the ball the most consistently?"

[Chieflongtee]

[QUOTE=BC MIST]
Having said that, what is wrong with MOI matching a set of irons for example, after getting the proper length and lie angle? Would they not all "feel" better? Would they not all then require the same amount of force to swing? Would they not all sqaure up at the same point in the downswing? Are Tom Wishon and Dave Tultleman both wrong when they say that MOI matched clubs are more likely to increase consistency?

QUOTE]

BC. You have a great golf mind. I don't think Dave Tutelman promotes either but here is part of his reply on another forum and I agree with what he says wholeheartedly.

http://forums.delphiforums.com/golfe.../?msg=163530.1

In fact, the single-length issue is completely independent of MOI. If you get a single-length set whose swingweight or MOI is too high or too low for you, you'll swing all the clubs badly. And if you get an MOI-matched set where the club lengths are too long or short for you, you'll swing all the clubs badly. Your clubs need to be heft-matched (whether MOI or swingweight) and they need to be the proper length (whether single-length or the more conventional progressive length).

[BC MIST]

Even with the "clarification" on gea, DL may have done himself more harm than good with his comments about MOI matching. Even though it may have been unintended, his shots at Wishon and Tutleman and their emphasis on MOI matching, did not go over well in the clubmaker community, as Tom W and Dave T are two of the most knowledgable and respected men out there.

DL single length iron concept is not without its merits, and while it is a break in tradition that few will go for, it will and has worked for some. Single axis swinging is a break in tradition, too, and am I ever glad. However, if the SL concept is going to work, IMO, the headweights of all the clubs should be the same. Simple. The cost of having heads manufactured this way may be too large for a small company to justify. Until that time though, I don't think that it will be as good as it could be.

I love my MOI matched set of clubs. They do all "feel" the same and do all swing the same, as well. I made a couple of swingweight matched clubs with the same heads and shafts as my own, and they just don't feel and perform as well.

[burgene]

My only issue is that DL has posted this exact same post on several forums to promote his clubs. Even though it has started some interesting discussions, it is only for self promotion.

[Chieflongtee]

Over the years there have been several one length club theories and several
OEM sets including Tommy Armour in the mid to later 90s . Hull Golf sold components made for this type of set up. It was gone in less than a year. There is a 30 day warranty though. I have never tried such clubs but I am inclined to believe that MOI matched clubs are the way to go.