The Effects of Shaft Flex

At this stage in the dynamic fitting process, the correct shaft length and lie angle for the player have been determined. The player will have seen his or her ball flights change as the fitter closed in on the right combination. However, if the shaft flex is not yet correct for the player, the desired ball flight results will not have been achieved.

The flex of the shaft as it relates to the player's swing, affects 2 variables in the ball flight - accuracy and trajectory.

The effect of shaft flex on accuracy

The flex rating of a shaft indicates it's ability to bend when a force is applied to it. In the case of the golf swing, the force being applied is the change in direction (downward) as the player begins the downswing. Since very little force is being applied to the shaft during the backswing, it is the downward acceleration of downswing that causes the shaft to flex backwards or "load". During the downswing, the "loaded energy" causes the shaft to flex back towards the straight position. With the correct flex, the shaft will be released in the straight position at impact. If the shaft flex is too stiff, it will not yet be released to the straight position, and will cause the clubhead to be aimed to the right at impact. If the shaft flex is too flexible, it will have released through the straight position before impact and will cause the clubhead to be aimed to the left at impact.

 

	*Player has correct shaft length *Player has correct lie angle If the ball flight is still a fade or slice, this indicates the player needs to use a more flexible shaft.
	*Player has correct shaft length *Player has correct lie angle If the ball flight is still a draw or hook, this indicates the player needs to use a stiffer flex shaft.

The effect of shaft flex on trajectory

The flex of the shaft also contributes to the trajectory of the ball flight. As described in the previous section, as the shaft unloads on the downswing, the position it is in at impact dictates the position of the clubface at impact. For example, if the shaft flex is too stiff there will be little or no unloaded energy coming from the shaft at impact. The result will be a low ball flight that lands short of the intended target. In addition, the impact will feel "hard" and "dead". If the shaft flex is too flexible, the unloaded energy will release too soon, causing the shaft and club face to be aimed high and left of the target. The result will be a high ball flight that lands short and left of the target. The proper shaft flex will result in a square clubface at impact and maximum energy released from the shaft. The result will be a ball flight that hits the target.