The Science behind Custom Golf Fitting

Aussie Custom Golf uses the latest technology and fitting techniques to obtain the best possible fitting golf clubs to all golfers - and one of the most important and often overlooked aspect of purchasing golf clubs either OEM or components is selecting the correct shaft for your swing. The following shows how complex this can be:

Balance and Feel

In assessing shaft performance, it is important to understand that a combination of flex, torque, kick-point, club weight and swing weight/MOI, given a certain club-head (weight, center of gravity and gravity angle) determines the balance and feel, and consequently the performance of a golf club.

Flex and Frequency Matching

Although there are no exact standards in the golf industrya general guide line for shaft flex selection is: 70 - 90 mph driver head speed = R; 90 - 100 mph = S; excess of 100 mph = X....Labelling can vary between manufacturers which means that R flex for one manufacturer can be the same as X flex in another brand. Shaft flex can be determined by the vibration frequency using a specific machine designed for this and a flex value can be determined....this is really the only way to compare one shaft versus another. By measuring this frequency at intervals along the shaft a graph can be produced to determine the bend profile of the shaft which can determine the comparison of tip and butt stiffness.

Torque

Shaft torque describes how much a shaft would twist given a certain twisting force (1 oz weight is used for the measurement). A proper shaft torque in relation to the shaft flex, kick-point as well as club-head weight and position of CG influences your ability control ball trajectory. In principle, the lower the torque, the harder the feel and the less twisting feel (club-head turning around the shaft). Shaft torque of steel shafts does not vary too much, at around approximately 3.0, but that of graphite shafts varies more. It varies in the range of 1.8 to 12.0, although 3.5 to 5 appear to be the most common graphite shaft torque. If the torque of a shaft is less than 3, it is considered as a low torque shaft in general. Low torque, stiff shafts are difficult to use without sufficient head speed, while with a higher head speed, a high torque soft flex shaft causes off the target shots to the left. Without a sufficient club-head speed, a stiff low torque shaft tends to cause a push to the right.

Kick-point

It refers to a maximum bending point of the shaft, and it is also called flex-point or bend-point. The lower the kick-point, more tip-flex the shaft, which in turn makes you feel that the club-head moves more through impact, while a high kick-point shaft tends to make you feel the opposite. However, a high kick-point shaft (lower ball flight) is much easier to control the direction. Since more golf clubs are made with low center of gravity club-heads, low kick-point shafts (higher ball flight)seem to have lost its role to play to some extent because the low CG tends topromote ahigher launch angle.

Shaft Diameter

Standard shaft diameters are 0.600" at the butt, and 0.335" at tip for woods and 0.370" for irons.Consistency in shaft torque (normally lower torque) appears to become available by making the shafts with larger diameters. Particularly, the larger tip diameter is effective in making shaft torque lower. However, it has to be understood that larger tip diameters make the kick-point higher.

Shaft Length and Weight

The standard shaft length is 35.5" to 36" for 9-iron and wedges and 44" to 46" for driver. While the standard shaft length of driverused to be43", many drivers are equipped with 45" shafts and occasionally even longer. Long irons such as 2-irons and 3-irons come with 39" shafts. As to weight, most steel driver shafts weigh between 90 to 120 grams, while graphite shafts are between 50 to 90 grams, with many ultra-light models weighing less than50 grams or lessdown to approximately 40 grams. The weight of traditional shafts for irons vary in accordance with the length of shaft. The length increment for 1 club is normally 0.5" or maybe 0.4" for MOI matching. The shaft weight of irons again vary from 50 grams to 130 grams and weight selection is critical in relation to feel and ability to generate controllable clubhead speed.

Shaft Matching

Modern technologies allow designers to control more over variables in shaft properties. When driver fitting for example a shaft can be broken down into three sections - butt, mid and tip to matchcharacteristics of any swing. Swing speed according to club length determines butt flex, transition/tempo determines mid flex and release point determines tip flex.Differential deflection shaft load matching or a frequency meter can be used to determine these properties and enable selection of the correct shaft for any swing. A proper shaft torque in relation to the shaft flex, kick-point as well as club-head weight and position of CG influences your ability control ball trajectory. In principle, the lower the torque, the harder the feel and the less twisting feel (club-head turning around the shaft). Shaft torque of steel shafts does not vary too much, at around approximately 3.0, but that of graphite shafts varies more. It varies in the range of 1.8 to 12.0, although 3.5 to 5 appear to be the most common graphite shaft torque. If the torque of a shaft is less than 3, it is considered as a low torque shaft in general. Low torque, stiff shafts are difficult to use without sufficient head speed, while with a higher head speed, a high torque soft flex shaft causes off the target shots to the left. Without a sufficient club-head speed, a stiff low torque shaft tends to cause a push to the right. - It refers to a maximum bending point of the shaft, and it is also called flex-point or bend-point. The lower the kick-point, more tip-flex the shaft, which in turn makes you feel that the club-head moves more through impact, while a high kick-point shaft tends to make you feel the opposite. However, a high kick-point shaft (promotes a lower ball flight) is much easier to control the direction. Since more golf clubs are made with low center of gravity club-heads, low kick-point shafts (higher ball flight)seem to have lost its role to play to some extent because the low CG tends topromote ahigher launch angle.

Other Factors

Also, it is important to know the fact that the shaft torque and the effect of that to the golf swings is influenced particularly by club weight and the factors determined by the position of center of gravity (explained separately). It is the feeling, not specific properties such as shaft flex, kick-point, and torque, that influences the performance of each individual golf swing. Golfers should find right combinations of a number of factors. For those who lack club-head speed, extra yardage is always a premium. Needless to say, longer golf shots require faster club-head speed at impact. Lighter golf clubs with longer shafts help golfers get a faster club-head speed. The length of golf shaft is another factor when looking for the right combinations of the above factors.

Shaft Manufacturers

Shaft manufacturers used by Aussie Custom Golf include Aerotech, Novatech, KBS, Nippon, Shimada, Qadra, Fujikura, Graphite Design, FST (Femco Steel), Grafalloy, Harrison, UST.