Shaft Weight vs Flex: Which One You Actually Feel
Weight is published in grams and means the same thing everywhere. Flex is a label with no standard behind it. Only one of those is a specification.
shaft fitting
Regular or Stiff When You Are Between Them: The Real Answer
Being between two flexes is not a close call you have to break. It means the chart has run out of resolution, and three other specs decide it instead.
Golf Shaft Flex Chart: Why Every Chart Disagrees
Every flex chart disagrees because no maker publishes a flex standard. What R and S actually mean, and the two specs that are measurable instead.