The key swing factors which determine the proper shaft flex are the clubhead speed, how forceful the golfer starts the downswing (transition), how much the golfer accelerates the club on the downswing to impact, and when the golfer unhinges the wrist cock angle on the downswing.
Clubhead speed is the starting point for the selection of the shaft flex/stiffness. In general, the faster the golfer swings the clubhead, the stiffer the shaft should be. However, clubhead speed alone by no means dictates how much the golfer actually bends the shaft during the swing. That is also determined by the two factors of the transition force to start the downswing and how aggressive the golfer swings the club on the downswing to the point of impact.
For example, if you have two golfers with the same clubhead speed yet one has a much more forceful move to start the downswing and a more aggressive downswing than the other golfer, the golfer with the faster tempo and more forceful transition move to start the downswing should be using a stiffer shaft than the golfer with the same clubhead speed who does not match the first golfer’s downswing force and tempo. This is because the transition force and downswing acceleration have much more of a bending effect on the shaft than the clubhead speed on its own.
Finally, when the golfer unhinges the wrist cock angle on the downswing determines how much the golfer will bend the tip half of the shaft. Golfers with a later to very late release of the wrist cock angle typically are best fit with shafts that are designed with a stiffer tip section while golfers who unhinge the wrist cock angle early to midway on the downswing are better matched to shafts that are created with a more flexible tip section.
In addition, the golfer’s own personal sense of FEEL for the bending of the shaft is also a very important factor in choosing the right shaft flex. Some golfers have the ability to actually sense when the shaft bends and how much it is bending during the swing. Other golfers do not. For those golfers who do have the ability to detect the bending feel of the shaft, it is very important that they be matched with a flex that allows them to actually feel the amount of bending and timing of the bending of the shaft to the degree their acquired preference for this dictates.
Some of these golfers with such a specific sensation for the bending of the shaft may prefer to play a much stiffer shaft than what their swing speed and swing characteristics may dictate, or some may prefer the feel of a more flexible shaft. Among golfers with such a sense of feel for the bending of the shaft, it is VERY important that whatever their preferred bending feel, the flex needs to be matched to that or else the golfer’s sense of swing timing, swing rhythm and fluidity of their release won’t be right.
For those of you that enjoyed last week’s post on driver shaft length, here is a video that Tom did with Golf Show Today: