Frequency is an absolute measure of the flex of a shaft. It is defined as how many times per minute a shaft oscillates. The units of frequency measurement are known as cycles per minute, or cpm. A shaft with a higher frequency is stiffer than one with a lower frequency. By using frequency as a method of comparing two different shafts, it is obvious which shaft is stiffer and by how much. Typically there will be 10 cycles between shaft flexes. Thus if one shaft registers 250 cpm and another is 270 cpm, there is a 2-flex difference between the shafts regardless of what flex the manufacturer claims them to be.
By assigning a specific frequency number to a shaft, the shaft can be closely matched to a player. For example, a player finds a driver that he hits very well, but wants the latest in club head technology. The repair professional is able to determine the current driver shaft’s frequency and can then match a head/shaft combination best fit to the player. Correspondingly, if the player wants fairway woods to match the flex feel of the driver, frequency can be used to determine what shafts to use and how to trim them to match.
A matched set of irons will have a similar number of cycles between each club in the set. The exact number will depend upon the shaft type, but there will be uniform increments between each club. This ensures that each club will feel and perform like all others in a set. Frequency can be used to duplicate a favorite iron set in the same manner as when choosing a driver. The cpm reading of a player’s favorite club can be measured and a set made with that frequency reading as the target. This process is known as frequency matching.
It is important to realize that there is no flex standard in the golf industry. Frequency provides an absolute way to measure the stiffness of a shaft. Shafts can then be matched to a player’s swing to improve performance. Frequency offers the ability to duplicate a favorite club, a demo club or a friends’ club that the player hits well. By duplicating this feel and playability and matching it through the set, frequency provides a concise measure of shaft performance. If you are still recommending shafts based on “R” or “S” flex markings, think again. Use frequency as a way of quantifying feel and performance. The resulting improvements will put your golfers well on their way to lower scores.