Flex is the most important factor in the shaft as it affects distance and direction. Getting the correct flex in your golf equipment is of the utmost importance. The flex is a rating of a golf club shaft's ability to bend during the golf swing. All shafts, no matter how stiff, exhibit flex under the forces of the golf swing. A player with a very fast swing will require a shaft with less flex, while a player with a slower swing will need a shaft with greater flex.
Flex is generally rated as Extra Stiff (XS), Stiff(S), Firm(F), Regular(R), Senior(S), Amateur(A) and Ladies(L). The less the bend in a shaft, the more control a powerful swinger will have. On the other hand, beginners and those with less powerful swings generally use a shaft with greater flexibility. The average swing speed with a driver is from 65 miles per hour for the beginner up to over 100 miles per hour for powerful swingers.
Different shaft manufacturers have differences in their specifications of flex. One manufacturer’s regular flex might be another’s firm flex. There are 2 methods of measuring flex. The more traditional Shaft Deflection Board and the modern Frequency Analyzer. Both are effective in the measurement of flex. Stiffness defines the bending characteristics of the shaft when weight is applied. Frequency is another way of defining stiffness and indicates how fast a club will vibrate with that particular shaft. The stiffer the shaft the faster the vibration. If you have a low swing speed, more flexible shafts will propel the ball more at the downswing. If you have a high swing speed, a stiffer shaft avoids lagging clubheads.
Torque is the twisting movement of the shaft during the golf swing. It is measured in degrees and shown as a rating that gives information about the 'twisting' characteristics. The higher the rating, the more the shaft twists and vice versa. The more torque a shaft has, the softer it will feel. A shaft with a 3 degree torque will feel much stiffer that one that has 5 degree torque. Every shaft, graphite or steel, has a certain amount of torque. Most steel shafts have up to about 3 degrees of torque. Torque however has a slight effect on ball trajectory, with the lower the torque, the lower the trajectory.
This defines the point where the shaft bends and affects the trajectory of the shot. The effect is small but measurable. A shaft with a high kick-point will usually give a low shot trajectory and more of a "one-piece" feel to shaft shaft. A low Kick-point will usually give a high shot trajectory and a feeling of the shaft tip whipping the clubhead through.
Kick-point will also affect the feel of the shaft. Some club specialists will dispute this by saying that the Kick-point and bend-point are the same. Bend-point is the highest point of the shaft when it is bending by applying pressure to both ends of the shaft. Kick-point is the highest point the shaft is bending, by clamping down the grip and pressure is applied onto the club head, like in the swing. There will be some shafts where both bending points are similar or very close.
The weight is the actual weight of the raw, uncut shaft before installation, in grams. Lighter shafts mean lighter total weight and therefore the prospect of additional clubhead speed and more distance.
Have you noticed that sometimes you will have a favorite club in a set of clubs that you just seem to hit better and more consistently than the others? This is most likely due to the fact that the spine in that club happens by chance to be correctly aligned in the club. The opposite is probably true for the club in the set that you can't seem to hit well at all!
Most golf shafts have some sort of minor irregularity in them that is inherent in the manufacturing process. This could be from the join of the shaft, the shaft not being perfectly round; the material of the shaft may be just slightly heavier on one side of the shaft than the other, or from an imperfection in the shaft material. This can cause the shaft to bend towards a certain point when you swing, causing the clubface to open or close.
You can get your clubs 'Spine Aligned' to sort this problem out. What they do is test the shaft to determine the characteristics of the golf shaft. Then the shaft can be installed so that the spine of the shaft is directly behind your target line. This way it does not affect the direction of your shot.
Parallel tip shafts are the same diameter for a specific distance up from the tip. Taper tip shafts reduce in diameter to a specific location on the shaft tip section. Taper tipped shafts and parallel tipped shafts do play similar to one another. The only difference between the two is tip diameter and weight. Taper tip shafts are constant weight, meaning that each shaft weighs the same from the long irons to the wedges. Parallel tip shafts have a descending weight through the set.
Pureing is a patented process that locates the most stable plane of the shaft, regardless of type or manufacturing process. Using a number of mathematical formulas, Pure computer software reveals how round, how straight and how stiff each shaft is and allows the operator to mark the dominant orientation that is most consistent. By installing each shaft so that the marked area is placed in a neutral position, every shaft or club within a set will have the exact same Plane of Uniform Repeatability (PURE). PUREing does not rely on human judgement – it is a science that is accurate to less than 1 degree.
Once the shaft is installed, you must then determine the proper length. This is just as important as flex, torque or anything else to do with the shaft. To determine the length of your club, stand up straight and have someone measure from the crease where your wrist and hand meet to the floor. Do this with both hands and take an average. It is critical that the irons be cut at a length that is suitable to that particular player’s height & distance from their hands to the floor.
The importance of length, according to research, is extreme: Ball impact that is 0.5 inches off-centre equates to a 7% loss of carry distance. An impact that is 1 inch off-centre equates to a 14% loss of carry distance. So, while longer shafts can certainly provide greater overall distance, the key to choosing the right driver is finding the longest one that provides a repeating, solid hit.
The following table shows what length of shafts you should consider for certain heights. If the crease where your wrist and hand meet to the floor is:
• 29-32 inches, your irons should be based on a 5-iron length of 37 inches
• 33-34 inches, your irons should be based on a 5-iron length of 37 1/2 inches
• 35-36 inches, your irons should be based on a 5-iron length of 38 inches
• 37-38 inches, your irons should be based on a 5-iron length of 38 1/2 inches
• 39-40 inches, your irons should be based on a 5-iron length of 39 inches
• 41 or more inches, your irons should be based on a 5-iron length of 39 1/2 inches
The length of the shaft is measured from the top of the grip to the base of the heel of the club as it lies on the ground.