Why Do You Fit Golf Clubs Using A L, R, S and X Designations

I had always known that there was no standardization in shaft stiffness from one manufacturer to another but felt that within the specific companies there would be a standard for these designations. In my recent work with The Ben Hogan Golf Co. to set up their Club fitting system using a wide variety of shafts, I even found this to be wrong. The following table summarizes the difference in the natural frequency of the various designations in the products of several Manufacturers.Natural Frequency Deviation in Cycles/Minute – cpm by Manufacturer for X, S and R shafts.
Shaft Stiffness              X        S       R
Manufacturer1             51      50      41
Manufacturer2             10      63      80
Manufacturer3             6        23      24
Manufacturer4             23      17      23
Manufacturer5                       13      22
Manufacturer6                       20      19
Manufacturer7             24      14      8
Highest of 7 Man.        51       63      80 
​Understand that if you are told you need an X stiff shaft for your swing, to get the right one from this group of manufactures, you are searching in a low to high range of 51 cpm. What does this mean? To get a fit that will give you your best distance and accuracy we have found you must be within 4 cpm of the correct natural frequency to fit your swing timing. It is up to the fitter to pick that shaft for you but he must know your natural frequency requirement and the frequency of the selected shaft when built into the club assembly. Trying to get the correct frequency by just knowing you need an R, S or X is hit and miss. We can see why it is mostly miss if you do not know the exact frequency you need and the frequencies of the club when built with the selected shaft. Using frequency as the designation is the most accurate way of designating club stiffness and does not change from manufacturer to manufacturer. This is the basis of the fitting system that has been developed by Perfected Golf Group, Ltd. .​As a Professional Club Fitter and Builder this is a great chance for you to participate in this advanced club fitting program. Currently we only have data on the listed Irons and Hybrids. Please Contact us for more detailed information on the this program. The Current selection of shafts with R, S and X flexes recorded are:
True Temper XP, Project X and Rifle
​FST Tour, Tour V, Tour FLT, Tour S, Tour 105 and Tour 90
​FST C-Taper
​UST Maniya Recoil 65, 95, 110, 660 and 760 ES
Nippon Mode 3 Tour 105, 120, 125 and 130
​Nippon NS Pro 750, 850, 950, 1050 and 1150
​Nippon Zelo 7 and 8​
This Package of shaft information and selection program can be purchased for $50.00. An additional shaft flex can be added for $5 if you furnish the frequency tipping data. It will be $8.00 if you furnish the shaft only. I will furnish instructions on providing the frequencies.