[BerntR]

For me, shaft flex has a lot to do with how well the club responds. I like to push hard on the shaft right before and into impact. With the right shaft I get added distance. If the shaft is to weak I don't get the reght kind of resistance to the thrusting. If it's too stiff I really have to add some extra with timing. But when it's just right.

I actually believe that the wrong flex will mess with the rhythm if you have some drive loading in there.

I played 9 holes / 2 balls with a set of vintage blades on Sunday. 8th tee - 3 iron. They would be ideal for practice if the shafts were stiffer, but they are regular: First ball a strong draw - almost a hook. Good distance. Second ball: Feels perfect - sweet spot - high draw - straight down the line - and 30 yards shorter.

Reminds me of when I used to play weaker iron shafts than today. I never quite figured out how to hit the ball to get the right distance. I had to deliberately max the thrust some distance before impact to get a good result. But I couldn't feel the difference between a good shot and one that flopped.

These things never happen to me when I play with stiffer shafts.

With stiffer shafts I get a much more predictable result and distance control. Higher COG possibly makes a difference too.

BTW, I can't stand the big offset in the game improvement clubs. It messes with my aiming.