The golf industry has tried to use simple non-technology based golf club fitting systems for years with less then great success. The club head speed system they primarily use will satisfy the ego for the big hitters but leaves many of them fighting hooks and slices. All of the golf club fitting technology based systems that are in use today are discussed in the " Technology & Testimonials" Link on the Home Page. The Swing Frequency Analysis "SFA" system introduced a new pure technological approach to golf club fitting technology based on the players swing timing. The "SFA" concept was born when Lloyd Hackman decided to use an accelerometer attached to the golf club shaft that would determine the acceleration pattern throughout the swing and could provide, through computer analysis, a swing release timing that could be matched by fabricating a club to the natural frequency that would match that timing. If you analyze the swing, as Lloyd has, the critical point in determining the natural frequency of the club is the time when the golf shaft starts to release or unload during the swing. That time subtracted from the time at which you impact the ball is representative of 1/4 cycle of the natural frequency of the club. Corrections are made through mathematical relations to the frequency dependent upon the club head speed and resulting centrifugal force that occurs between release and ball impact. The computer easily makes such corrections to select the proper golf shaft to get back to straight and square. Thus, the unit provides the ultimate in golf club fitting. It identifies the exact time for the release of the club and ball impact and matches the response time between club release and ball impact to a natural frequency of a club which will come back to straight and square during that period. You can find a more detailed explanation of this process at the Link "Specifications" on the Home Page. The is the only golf club fitting system which has the basic purpose of selecting the golf shaft that will return to straight and square at ball impact.
Such a golf club fitting will provide the player with maximum performance through club head speed and club head square. The instrument that has resulted in the "SFA" system was initially conceived in the 80's and finally developed in l993 when all the required components came together in computer analysis and sensor miniaturization. The "SFA" system was first introduced at the Professional Club Makers Association meeting in Louisville in September of l994. The manufacturing phase began in late October, l994. Perfected Golf Group, Ltd was formed in 1994 to develop and market the "SFA" system that eventually became FitChip. The Lotus Golf Division was then formed in 1995 to use the golf club fitting system and build custom fitted golf clubs.
Knowing how the Golf Shaft works is the important step in shaft selection. The selection of the proper golf shaft is not simple. In the past the best way to make this selection was by trial and error. There are three things wrong with this system of golf club fitting.
1. maintaining a good swing for the time it takes to try all the golf shaft possibilities.
2. The cost if you have to buy all of the golf clubs or golf shafts you want to test.
3. There is a limited range of the golf shaft stiffness available off the shelf for testing ( we find that only 40% of the players that go through our golf club fitting system fall within the range of off the shelf golf shafts).
However, by knowing the time between the shaft release point and ball impact and the relationship of that time interval to the natural frequency of the golf shaft / club, you have the basic starting point for the golf shaft selection. As pictured below the critical golf shaft selection time or kick initiation, with a driver, occurs in a .05 second interval during the down swing. This interval represents the difference between selecting a 170 CPM golf shaft and a 320 CPM golf shaft for the player. Since the FitChip golf club fitting system takes 25 readings during this interval it is by far the most accurate way of determining the proper golf shaft stiffness.
You must also understand that, how much you load the shaft is not important, it is only the time interval that makes this first basic frequency selection. Some people do not grasp this fact but it can be easily proven by putting a shaft in a frequency meter and deflecting it several different amounts, the frequency will always remain the same independent of how much you deflect or load it.
I call this a basic frequency because there must be a correction made to this frequency to arrive at the final golf club fitting or golf shaft selection. The correction is based on the centrifugal force acting on the club head. If the shaft is flexed or curved during the down swing the centrifugal force is trying to straighten the shaft thus reducing the amount of spring action needed to bring the shaft back to straight and square. If there was no centrifugal force the basic frequency would be the answer but since we are dealing with a golf swing that generates club head speed and as a result centrifugal force, we must reduce the necessary spring action or frequency as a function of the magnitude of the centrifugal force. Since club head speed is the precursor to centrifugal force the correction relationship can be derived as a direct function of club head speed. Therefore the relationship will describe the amount the frequency is to be reduced as the club head speed gets greater. This part of the gof shaft mechanics goes against the general golf shaft or golf clb fitting theorys of the industry, because when two players have the same time interval between release and ball impact the one with the higher club head speed gets a softer golf shaft then the player with the lower club head speed. This is because the player with the higher club head speed is getting more help from centrifugal force and needs less spring action to bring the golf shaft back to straight. Having made this correction you now have the frequency for the club that matches the players swing timing or swing frequency and the perfect golf club fitting.
As an example of a misfit shaft the following pictures were taken from a video of a long drive competitor. This individual generated a clubhead speed of 134 mph. Of course , the golf industry would give this individual as stiff a shaft as possible. However the industry dose not consider swing timing but only clubhead speed.
In the first frame of the video the player is at the top of the swing. In the second frame we selected he is loading the shaft. In the third frame selected the shaft is starting to unload.
In the fourth photo the shaft is back to essentially straight indicating the shaft has unloaded to the point where it has released its stored spring energy. This should occur at impact for the players best performance. The shaft is slightly ahead of the shaft as should be expected because of the Centrifugal Force affect. Photograph five shows the head substantially ahead of the shaft and much more then can be justified with the Centrifugal Force affect. Photograph six is even more dramatic when it shows the shaft with less forward deflection then in photo five indicating that the shaft is starting to recoil and losing speed with respect to the individuals input speed prior to impact. Such a dramatic shaft mismatch could cause a lose of 10 to 20% of the individuals potential club head speed. With the very early release of this shaft, the shaft has to be much to stiff for this individual.
You can achieve this first mode frequency in any style or configuration of golf shaft. Many people get concerned about kick points in the shaft. If the shaft is properly fitted to the players swing the high kick point will provide the best club head speed because it will give more shaft deflection for a given frequency. The greater deflection results in greater club head speed when the shaft is back to straight. If the shaft is back to straight at impact the launch angle is determined by the face angle irregardless of the kick point. Low kick points would be for those players that can not be fitted because of a wide variation of swing timing from swing to swing. The low kick point will cut down on the dispersion caused by shaft flex timing since there will be less flex or head movement.
Shaft torque is another part of the shaft mechanics that most club makers do not fully understand. Steel shafts that have always been considered as having low torque values were never considered as feeling bad but many clubmakers feel that when a graphite shaft has the low torque value it has a bad feel. I believe feel is in the flex and timing of the shaft, not in its torque value. The greatest affect of shaft torque on club performance occurs when the player hits the ball off the sweet spot, resulting in greater dispersion. In this case every player can benefit from a low torque value. The deflection of the shaft in torque plays very small roll in squaring up the head at impact because this deflection is very small. Why is this deflection small? The golf shafts torque value is designed primarily to provide the strength needed to resist breakage of the shaft during toe impacts. By calculating the acceleration of the club head weight during the swing and the ball acceleration off the club face the torque from the toe impact is 8.75 times greater then the torque on the shaft during the swing. So, if you got 3 degrees on toe impact you would only get .34 degrees during the swing.
Spine alignment is another aspect of golf shaft mechanics. There are two different shaft conditions that cause what has come to be called a shaft spine. There is also the possibility of the combination of the two types.
1. A shaft with a slight bow in it. The bow can be determined by rolling the shaft on a flat surface or on a spine alignment tool the bow will end up with the tip lower then the butt.
2. A shaft with a hard side or more material on one side then the other such as a seam or over lap of material might produce. The hard side will always be on top in a spine alignment tool.
If you align the shaft in the club so that the shaft bows away from the target or the hard side of the shaft is toward the target, when the shaft flexes during the swing it will be stable and flex on a straight back path. If the shaft flexes back on a straight or stable path it will return to the ball on that path. When the shaft is not aligned as suggested it will flex to the inside or outside of the straight back or stable line causing the shaft to return to the ball off line.
If you have questions? Send them to fitchip@sbcglobal.net
