proper shaft, stiff or regular flex

[WUTiger]

One factor related to "which flex is best" is clubhead speed.  And, one factor influencing clubhead speed is weight of the shaft.

This summer I reshafted my X20 Tours from PX 5.0 (115 grams, FCM* = 5.5) to NS Pro 8950GH (97 grams, FCM = 5.0). I picked about 12 yards per club in distance, and have more consistent distance gaps from club to club.

I got away from Stiff shafts (except for Wedgeflex) about 2009. But, I have found recently I can hit some of the superlight shafts (85 grams in steel) in Stiff. Problem:  the superlights are too light - I can't feel when I'm at the top and tend to overswing. In irons, I tend to get best from shafts about 100 grams in weight.

Back to flex : FCM is a way to overcome the fact that golfdom has no industry standard for R-flex and S-flex.

• The S-Flex Dynamic Golf S300 has FCM = 5.8, but weighs 130 grams.
• The S-Flex PX 6.0 has FCM = 6.5, but only weights 120 grams.

As others have said, the best way to tell is to test out different clubs on the launch monitor, and see how the ball flies with each.

_____________________________

*FCM = Frequency Coefficient Matching, a method devised by Royal Precision (think Kim Braly of KBS shafts). Clubfitters have adapted it to compare shaft flex across different manufacturers and shaft models.

[Gibby13]

This is an interesting thread.  I am a 7 cap that has used stiff shafts since my 20's, getting a new set of Mizuno irons every 2-3 years.  This past week, I played with a customer in NJ with a rental set of Speedblade irons.  I shot a 74 in a harsh wind & it wasn't until after the round I looked down at the clubs to take a picture that I noticed that the shafts were Regular.

Now I'm confused, not knowing if I striped everything because I was just on that day moreso than normal, I was using R shafts or the Taylormade irons just suit me better....