Originally Posted by Righty to Lefty
... Shaft flex is almost irrelevant because there is no standard like there are for weight and torque and so the flexes vary from company to company. ...
True, there's no industry standard for regular or stiff, but three organizations have devised methods for comparing shaft flexes across manufacturers.
The Rifle crew devised a measurement which allows you to compare the relative stiffness of different model and manufacturer's shafts. Called Frequency Coefficient Matching, it was developed by Royal Precision, originators of the Rifle and Project X shafts. (RP went on hard times a few years back, and True Temper bought the Rifle and PX names.)
Anyway, FCM compares different shafts on a deflection board, and determines relative stiffness. The cycles per minute CPM of a shaft would come out 248 for a Dynamic Gold SL R-flex, and 255 for a Project X 5.0 "regular" shaft
To get FCM, you drop the 200-digit from the cycle rating, and convert it into a two-digit decimal. So, the SL- R ends up with an FCM of 4.8, a Project X 5.0 has FCM = 5.5 (yes, it can get confusing).
Several TST members have posted an FCM iron shaft summary chart from 2011 (source = GolfWRX). (It needs to be updated with all the new iron shafts available).
Fitting reps generally rank weight, then flex (with good FCM comparison), and then kickpoint/bendpoint. The kickpoint describes the launch tendencies of the shaft; but, recent tests show KP/BP to be a fine-tuning consideration.
Also, GolfWorks developed the MPF Shaft Ratings. It's a 4-digit code that takes into account swing speed and other factors to determine a cluster of shafts which would fit your swing. See http://www.ralphmaltby.com/265
Third, Miyazki has come up with its own 4-digit International Flex Code for graphite shafts. (Maybe someone else can explain it... I'm still trying to crack the code.)
Edited by WUTiger - 5/16/14 at 3:19pm