Golf club fitting
The golf club fitting or custom fitting is the adaptation of golf clubs to the geometry of the human body and the individual swing movement during the stroke.
General
The golf clubs offered in stores are generally standardized mass products that are tailored to an average build player with average athleticism. The manufacturers move in the field of tension between the cheapest possible production and the largest possible target group. Players who fall out of the norm are served worse as a result, for example the supply of left-hand rackets is significantly lower than that of right-hand rackets. The golf club fitting aims to counteract this by individually adapting the golf clubs to the physical characteristics and technical skills of a specific customer, allowing them to better exploit their playing potential.
Golf Club Fitting Methods
When it comes to golf club fitting, a general distinction is made between static and dynamic club fitting .
The static fitting
Depending on the body size (arm length, leg length and finger length) every golfer has different physical requirements to hit a golf ball optimally. With the help of a static fitting, the body dimensions are determined accordingly, so that, for. B. the length of the shaft, the grip strength and the flex (flexibility) of the shaft can be determined.
There are different systems of which body measurements are determined in which way and which conclusions can be drawn from them. Common methods are described below by way of example, but they are not state-of-the-art in all cases.
Shaft length
With static fitting, body height, hand-floor distance while standing and the size of the hand are often measured. The second step is to measure the distance from the beginning of the wrist to the floor. For this measurement, the golfer stands upright in golf shoes and lets his arms hang loosely. The right-hander measures the distance on the left hand, as a left-hander one takes the right hand. For example, if you take a standard value of 36 inches (91.5 cm) for men and 35 inches (81.5 cm) for women, the following tables would result:
Table men: hand-floor distance corresponds to the following shaft length
| 79.0 - 84.0 cm | minus 1.0 in |
| 84.0 - 89.0 cm | minus 0.5 inches |
| 89.0 - 94.0 cm | 5 iron = 38 inches |
| 94.0 - 99.0 cm | plus 0.5 in |
| 99.0-104.0 cm | plus 1.0 in |
| 104.0 - 109.0 cm | plus 1.5 inches |
| 109.0 - 114.0 cm | plus 2.0 in |
Table women: hand-floor distance corresponds to the following shaft length
| 69.0 - 74.0 cm | minus 1.0 in |
| 74.0 - 79.0 cm | minus 0.5 inches |
| 79.0 - 84.0 cm | 5 iron = 37 inches |
| 84.0 - 89.0 cm | plus 0.5 in |
| 89.0 - 94.0 cm | plus 1.0 in |
| 94.0 - 99.0 cm | plus 1.5 inches |
| 99.0-104.0 cm | plus 2.0 in |
It should be noted, however, that there is no official standard for exactly where the mean value is, so an indication of "+2.0 inches" may be misleading. Nevertheless, these relative terms have become common in everyday language.
Grip strength
To determine the grip strength of a golf club fitting, measurements are taken from the wrist to the fingertip of the middle finger. The standard handle thickness for men is 22.8 millimeters and for women 21.7 millimeters in diameter. The grip thickness is measured in the assembled state five centimeters (approx. Two inches) below the end of the grip.
| Length of the wrist to the fingertip | Middle finger length: 5.1–7.6 cm | Middle finger length: 7.6-10.2 cm | Middle finger length: 10.2 cm and more |
|---|---|---|---|
| under 14.5 cm | Junior | ||
| 14.6 - 16.5 cm | Ladies | Women +1/64 | Women +1/32 |
| 16.6 - 17.8 cm | Men −1/64 | Men's | Men +1/64 |
| 17.8-19.7 cm | Men's | Men +1/64 | Men +1/32 |
| 19.7-21.0 cm | Men +1/64 | Men +1/32 | Men +1/20 |
| 21.0 - 22.2 cm | Men +1/32 | Men +1/20 | Men +1/12 |
| 22.2 - 24.8 cm | Men +1/16 | Men +1/12 | Men +1/10 |
A size correction can be made by adding and subtracting from the standard diameter.
| 1/64 | = | 0.4 mm |
| 1/32 | = | 0.8 mm |
| 1/20 | = | 1.3 mm |
| 1/16 | = | 1.6 mm |
| 1/12 | = | 2.1 mm |
| 1/10 | = | 2.5 mm |
As a rule, the handles of golf clubs are made of rubber, so there are numerous degrees of hardness and colors on the market. For an even better grip when striking, there are textile-reinforced handles. A distinction is made between half-cord and full-cord handles, which have a rougher surface than rubber handles. Leather handles are rare due to the high price. They dampen most of the vibration and prove to be extremely durable in wind and weather. In addition, the slip resistance remains stable even with wet hands and light rain.
An incorrect grip strength can, for example, affect the mobility of the wrist and thus the swing. It is also possible to twist the handle in the hand during the swing and can possibly be attributed to an unsuitable handle.
Shaft flex
Nowadays golf club shafts are usually made of steel or graphite. The selected flex (flexibility) for static fitting mostly depends on the club head speed the player achieves. This is either measured during the fitting (which, strictly speaking, already goes in the direction of dynamic fitting) or one builds on an estimate or an indication of the player that he has determined himself.
Golf shafts made of steel have a higher weight and a direct transmission of vibrations. This highly perceptible feedback enables the player to draw conclusions about the impact moment. But there are also players who find the vibrations annoying, not least because of health restrictions such as arthritis. These players often choose lightweight graphite shafts that can be accelerated faster and dampen vibrations.
Letters are noted on the golf shafts that should provide information about which shaft flex category you are holding in your hands. The following examples are approximate, as there is no uniform standard here either:
- Ladies (L) - intended for women, men and seniors with very low swing speeds. For a shaft with the category "L", this is approx. 60 mph.
- All-round (A) / Senior (S) / Medium (M) - Golfers, especially strong women or men with a moderate golf club swing speed (approx. 60–75 mph).
- Men Regular (R) - a shaft with the category "R" is suitable for sporty women and men who tee off with a normal swing speed (approx. 75–90 mph).
- Stiff (S) - is a shaft that very sporty men and good golfers play with a high swing speed (approx. 90-100 mph).
- X Stiff (XS) - Professional golfers with extremely high swing speeds (from 100 mph) often opt for this shaft.
The swing test - the dynamic fitting
The dynamic golf club fitting is primarily based on the analysis of the golf swing, whereby the club is adapted to the existing swing pattern. Here, for example, the golfer's swing path (from outside to inside or from inside to outside) is determined. This can cause the club face to cut into the ball at the moment of impact, giving it a sideways spin, which manifests itself in a trajectory that turns left or right.
Lie angle
The lie of the golf club is often optimized during dynamic fitting. This angle is located between the shaft and the sole of the club head. It should be aligned so that the underside of the club head is exactly parallel to the ground when the golf ball hits it. A tilted clubface usually leads to deviations in the flight of the ball.
Some club manufacturers offer golf clubs with different lie angles; these are e.g. B. in 1-degree steps up to a maximum of 5 degrees steeper or flatter. In addition, some club heads can be bent. Usually these are forged club heads, but there are also some cast club heads that can be bent - primarily this is a matter of material.
There are different methods of measuring the lie angle at the moment of impact:
Lie boards
Balls are hit from a hard black plastic plate, with the aid of which the fitter can read whether the club head is touching the ground with the tip or the heel or whether the golf ball is hit in the sweet spot (the center of the club face).
Lie sticker
In this method, the clubs are provided with stickers, so-called face tapes and lie tapes, with which the golfer hits practice balls from a range mat. The imprint of the ball on the sticker then allows conclusions to be drawn about the lie angle at the moment of impact.
Golf simulators and launch monitors
With the help of these devices, which work on a radar and / or camera basis, many values can be measured or calculated. These include, for example, club head speed, swing path, loft and lie at the moment of impact, spin rate and distance of the strokes. Based on the determined data, an individual profile of the swing can then be created, which in turn forms the basis for club fitting. Often these devices are also used for training purposes in that the determined data is saved and measured again after a training period and compared with the previous values.
Kick point
The kick point is the area of the golf club shaft that flexes the most when teeing off. Depending on where the kick point is (more in the direction of the grip or more in the direction of the club head), this can change the take-off angle of the golf ball.
Torque - twisting
The term torque describes the twisting (from Latin torquere = "turn", plural identical; English torque ) of the shaft around the longitudinal axis. The torsional stiffness of a shaft can influence the flight of the ball if the balls are not hit in the middle. For this reason there are shafts with different torque values.
The MOI fitting
MOI fitting should not be confused with MOI matching. In MOI matching, golf clubs are adapted to each other in such a way that they have the same moment of inertia and can therefore all swing with the same force. The MOI fitting determines the MOI (mass moment of inertia) which best suits the golfer and his strength / swing. This is done dynamically with tests of golf clubs with different mass moments of inertia. Golf clubs with different head and shaft weights as well as different club lengths are used. As can be seen from the formula, the club length is particularly important to measure, as this is included in the MOI formula as a square. Once the appropriate MOI has been determined, the golf clubs for a set are brought to the same MOI using MOI matching. Other influencing factors such as B. Shank flex, lie angle and handle size are also part of a good MOI fitting.
Explanation of terms: MOI = Moment of Inertia = moment of inertia ; describes a resistance or the force which one has to use to accelerate an object in rotation.
Around the year 2002 the first MOI frequency measuring device came onto the market, which in connection with the weight and the center of gravity of the golf club enables a reliable determination of the MOI (mass moment of inertia) of the golf club.
The physical background for the MOI fitting is the mass moment of inertia of each body, which is accelerated in rotation. It doesn't matter whether it's a hammer, an ax or a golf club. According to the formula m × r², initially shown simply, the mass (m) of the head (head weight), the mass (m) of the shaft (shaft weight) and the distance (r) of these masses from the pivot point are of fundamental importance for the swingability of a golf club. In fact, it is not just the total mass of the head and the shaft, but the sum of the infinitely many individual mass points × their radius squared, which is represented in the following formula:
- . (MOI formula, unit is kg m ^ 2)
The lack of a measuring device until 2002, the difficult determination of the MOI and the requirements for club construction explain why the MOI fitting has only been increasingly found in golf club fitting in recent years.
A special feature of the MOI system is that you can bring all irons in one set, from the wedge to the long irons, to a uniform MOI. This is known as MOI matching or MOI harmonization. Based on the MOI of a medium iron, the shorter irons are provided with correspondingly heavier heads and the long irons with correspondingly lighter heads, so that the same inertia can be used for all irons in one MOI set.
Even drivers that have a corresponding range of weight screws can be matched to the appropriate MOI.
See also
literature
- Jeff Jackson, David Stewart: Total Clubfitting in the 21st Century. A Complete Program for Fitting Golf Equipment. Dynacraft Golf Product, Ohio, ISBN 0-9619413-6-7 .
- Ralph Maltby: Golf club design, fitting, alteration and repair: the principles and procedures. Faultless Sports, Newark 1974, OCLC 1207444 .
- Tom W. Wishon, Thomas Grundner: Search for the Perfect Golf Club. Sports Media Group, Ann Arbor, Michigan 2005, ISBN 1-58726-185-5 .