You may not know that the sand wedge is the heaviest club in your bag, and contrastingly the driver is the lightest. Regardless if you knew that or not, weight is one of the club's most confusing specifications. Since the 1930's, golfers have been paying attention to weight, and using a concept describing the feel of a club's (dynamic) weight, "swing-weight". In order for you to understand more about the mechanisms of how a certain club with different club weight and swing-weight is translated into your feel, it is imperative to understand what the club weight, including the swing-weight, and shaft properties do to your feel.



Swing-weight (SW) : Swing weight, which is different from the measure of a club's total (static) weight but rather how that weight is distributed throughout the club, is a very confusing concept. Technically, SW is determined by the total weight of a club (club-head, shaft, grip) and the static balance point. It is determined by a number calculated by dividing the distance between the grip end and the balance point minus 14" (14" scale method) by the club total weight, where D0 is 213.5 inch/ounce. In this system, C means lighter than D, and D3 is heavier than D0. Theoretically, it could go as light as A0, and as heavy as F9. (If you would like to buy a SW scale, it is available from Golfsmith.)



For many years a SW of D0 was considered ideal for average golfers, and D2 or D3 for stronger players. This system was developed in 1930's to make or choose the correct golf clubs in terms of feel of club weight. At the time, and until as recent as the early 1990's, the materials used for club making were limited to steel and persimmon, and therefore weight distributed throughout the club is affected mostly by the shaft length and the weight of club-head.



However, modern golf clubs vary in weight of components such as grips, shafts and club-heads. In addition, modern golf club shaft properties, including flex, kick-point, torque, etc., vary more significantly than older clubs -- which all contribute to your feel of a club weight.



In principle, the stiffer the shaft, the lighter the feel. If you replace steel shafts of your golf clubs with lighter graphite shafts, the swing-weight should become heavier while the total weight of the clubs becomes lighter.



Let's take a look at an example. Take a shaft with a grip and no club-head at the tip, and try to swing it. It should flutter, and making it difficult for you to control the movement of the tip. But if you put weight on the tip, it stabilizes and you get the feel for the control over the tip end. This means that a lighter club is difficult to control, although it may help increase club-head speed. It is apparent that you need to have a balance between controllability and club-head speed.



Taylor Made Burner Bubble debuted in 1994 is probably the first golf club successfully  introduced to the market with a heavy SW (D8). With a unique shaft geometry and the heavy SW, it changed the way to make golf clubs in terms of SW. After that, the surge in lighter, longer shafts and lighter club-head materials and bigger club-heads further changed the meaning of "traditional" SW because they changed a club's balance point and overall weight.



Goldwin's AVDP, for example, employs 13-gram grip and a feather light shaft together with the aluminum based club-head, resulting in a super-light driver with a very heavy SW of E2. If the same club-heads are used for clubs with different shaft weight, the swing-weight of clubs with lighter shafts (i.e. graphite shafts) becomes heavier. Although some manufacturers use different club-heads in weight, many club makers use the same club-heads.



Ping employs the Thermocomp back-weight system for the new woods, which comes in a variety of weights that allows to tune the swing-weight of the woods regardless of the finished length of the club and/or the shaft weight.



Constant MOI (Moment of Inertia) Technology - Tommy Armour introduced the 845 evo series irons (v-25 forged model and v-31 cast model ), claiming that the irons are built for a zero-slope constant MOI. It compares the evo with popular traditional irons having D2 swing-weight and a positive MOI. The company's explanation goes to the point - the ultimate combination of stable long irons and workable short irons - in which it implies that the MOI method is better than the traditional 14" scale method in terms of the weight balance of the irons.





MOI (Moment of Inertia) - MOI is a very difficult concept to understand. Skip this paragraph if you do not want to become too technical.



According to a dictionary, it is defined "Of a body about an axis, , where m is the mass of a particle of the body and r is its distance from the axis", or "This is similar to inertia except that it relates to rotating movement rather than linear movement". The linear movement is the tendency of an object to remain motionless if at rest and to keep moving in a straight line if already in motion.



The moment of inertia, however, is the tendency of an object to resist being accelerated (or decelerated) when it is rotating. The polar moment of inertia is the rotating movement around a vertical axis through the center of rotation. It greatly affects steering and handling response in an automobile. The greater the length of the axis the greater the polar moment of inertia. By having the heavy components of a car such as the engine and transmission between the two front wheels, the polar moment of inertia is low so that the tires can easily change the direction of the car. The point is that as the MOI is calculated as mass times the square of the distance, in order to make a set of MOI matched clubs with longer and/or lighter shafts, the club-head weight has to become lighter. There is a very good article regarding this subject from clubmakers' resource "What does swingweight really mean?" by Dave Tutelman.