July 2008 Golfsmith Clubmaker Back to Main
Snake Eyes Irons
tech talk
Basic Best Practices for Fitting Irons
by: Jeff Sheets

The Custom Fitting Difference

Today, the only way for custom club makers to differentiate themselves from others is through custom fitting. Whether competing against other club makers in your area or the original equipment manufacturers’ (OEMs’) products being marketed worldwide, custom fitting golf clubs is a service that bonds you to your customers, creating relationships that can go on for years.

At Golfsmith, we have educated tens of thousands of clubmakers in the art of custom fitting golf equipment. Our one-week Advanced Custom Clubmaking and Fitting School, for example, has been the launching pad for many a custom fitter. While there is a tremendous amount of material to absorb over the course of one week, I have consolidated some of the course’s basic iron fitting information here, for the novice fitter. This guidance will provide some insight into what we look for during an iron fitting.


Getting Ready: Your Fitting Clubs

Every club fitter needs to have a variety of fitting clubs to work with. The specs of these clubs need to be documented so you have a reference point on which you base your measurements. If there is an assortment of popular shafts that you build frequently, it is good to assemble your fitting clubs using these shafts, both steel and graphite versions in various flexes. Likewise, we also recommend building fitting clubs at lengths ranging from 1" under to 1" over standard.


Basic Measurements

Here are the primary specifications we are going to measure in order to properly fit a set of irons to a golfer:

  • Swing speed
  • Club length
  • Lie angle
  • Grip size
  • Swingweight/moment of inertia (MOI)


Swing Speed

The fitting should begin with measuring the golfer’s clubhead speed. There are various devices available for taking this measurement, such as the Auditor Swing & Ball Speed Analyzer, the Zelocity PureFlight System, or a launch monitor such as the Vector Pro or Zelocity PureLaunch. Each of these electronic units provides an array of swing or ball flight information. Research each to determine what best suits your fitting objectives and budget.

Since we are fitting the golfer to irons it is best to measure clubhead speed using an iron. This can be done with one of the golfer’s own clubs or with a fitting iron. You will find that measuring swing speed using a shaft flex and club length that best fits the golfer yields his or her highest attainable speed.

Use our Shaft Selector tool to find
specs on hundreds of shaft models.
With the swing speed identified, it is possible to find a suitable shaft model for the golfer. The decision between graphite and steel depends on the golfer’s desires, needs and budget. As a rule of thumb, stronger-skilled swingers usually benefit from heavier shafts, so either steel or standard-weight graphite shafts often are the ticket for them. Recreational golfers can benefit from a wide range of graphite weights or lightweight steel shafts. And senior and women golfers are most commonly fit into lightweight graphite, which provides better control using slower swing speeds.

Refer to Golfsmith’s Recommended Swing Speed Range (RSSR) ratings for every shaft we sell. This makes the marriage of the golfer’s swing speed and a good-performing shaft quick and easy. In fact, using our website’s shaft selector will allow you to query through hundreds of shaft models based on their individual specs, such as RSSR, CPM ratings (trajectory, weight and torque) and dimensions.

For many golfers, budget will be a driving factor in their shaft choice. For the fitting process, it is good to identify a couple of different models for consideration.


Length and Lie Angle

As you proceed with the fitting, you will want to measure the golfer’s lie angle and club length requirements. This is where your fitting irons really come in handy. Pressure-sensitive impact tape is necessary to place on the face and sole of the fitting clubs.

Have the golfer hit balls off of a dynamic lie board. As the sole of the club impacts the board, a mark is left on the impact tape that shows the contact point. Likewise with the face: The ball’s impact location will be evident on the tape.

Some club fitters remove both pieces of tape following every impact and place them on a sheet of paper for reference. This isn’t necessary if you take notes on impact location after each hit.

When reviewing the sole sticker, first you want to determine what part of the sole is making contact with the ground. If the iron is properly fit to the golfer’s lie angle spec, the impact location will be in the center of the sole. An impact location toward the toe indicates that the iron’s lie angle is too flat for the golfer. A mark toward the heel tells you that the lie angle is too upright. For every ½" that the impact location is away from the sole’s center, the lie angle needs to be adjusted 1°. For example, if the impact location is 1" away from center, toward the heel, the golfer’s ideal lie angle spec is 2° flatter than the fitting iron’s lie.

Too flat; just right; too upright.
The face impact sticker will also tell you some important information. It is important to identify the consistency of clubface impact. If the golfer is able to hit the ball in the center of the face on every shot, then you know that the club is at a good length for the golfer to control.

If impacts are scattered all over the face, then the club is too long for the golfer to control with any consistency. Give them an iron that is ½" shorter and retest. We would expect for the shot pattern to tighten up with the shorter club. If it does, then focus on the club’s length for the golfer’s spec. If not, provide a fitting club ½" shorter and retest again. For most golfers, I do not recommend going shorter than 1" under standard length, because the head weight of the club will usually be very light at a shorter length. This limit will provide the golfer the best opportunity to develop hand-eye coordination for the future.

Impact stickers on the club face can
help determine proper club length.
If the golfer displays good ball striking consistency with the fitting club and desires to go to a longer length, use the impact tape to verify if the consistency remains using the longer spec. Test in ½" longer increments as you make the final determination of club length.



Grip Size

The next measurement is a static one in which the golfer’s hand size is gauged to determine their appropriate grip size. Our Grip Sizer quickly identifies the recommended grip size for any golfer’s hands. Alternately, use the older, proven method of determining size by having the client grasp grips of various sizes. (Of course, you will need to have a variety of grip sizes on hand to do so.)

A proper grip fit is determined when the fingertips of the golfer’s upper hand (the left hand for a right-handed golfer) barely make contact with the palm. If the fingertips can dig into the palm, the grip is too small. When a large gap exists between the fingertips and palm, the grip is too large.

Too small; just right; too large.
More importantly than a proper visual fit is that the grip feels comfortable in the golfer’s hands. For example, a golfer with arthritis may find grasping a properly sized grip to be difficult or uncomfortable. In cases like this, a larger grip is recommended even though the Grip Sizer or visual inspection points to a smaller grip size. Let comfort guide the final fit.

Select a grip model in the proper size that the golfer likes. A variety of styles are available with an assortment of textures, hardness and design options, including a variety of attractive colors.


Swingweight and MOI

Both the static weight and swingweight of the irons are important factors affecting feel and control. Since you have determined the proper length and lie angle, you can direct your focus toward the final weight of the clubs. If the golfer likes any of the shafts used in your fitting clubs, it will be easy for you to project the irons’ final specs. Since most iron heads are available within standard weight ranges, it is easy to determine the swingweight if you already have the appropriate shaft and grip information to help balance out the club.

If necessary, use lead tape on the back of the club to increase the iron’s swingweight. Allow the golfer to hit shots and determine the weight that is the most comfortable, provides the greatest amount of control and yields the best ball flight performance. This is an exercise that can be quickly performed if the golfer identifies a feel he or she likes immediately. However, some golfers are much more mechanical and have little sense of feel. Adding and removing lead tape until the best ball flight and control are observed is the objective.

Measure your fitting club to determine its specifications. Note the swingweight or its MOI value if you have an MOI scale. Most of the newer iron models available from Golfsmith are weighted in 8-gram increments. As opposed to using the older, 7-gram increment standard, 8-gram weighting leads to a naturally MOI-matched set (assuming a ½" length increment between clubs). So if the fitting club is a 6-iron, and the client likes it swingweighted to D1, produce the golfer’s new set of irons using D1 as the target for the 6-iron. If you use 8-gram increments, each shorter club will be half a swingweight point heavier than the 6-iron, and each longer club will be half a swingweight point lighter than the 6-iron. The end result is an MOI-matched set of irons with progressive swingweights.

If the set of irons you are fitting has 7-gram weight increments, then assemble all lofts to the swingweight that the golfer hit best.


Putting It All Together

Assembly is the easy part for most club makers, but learning to fit is the road less traveled. You can begin by fitting yourself to better understand the dynamics of each of the measurements, and from there move on to fitting family, friends and other golfers. While the satisfaction of building your own equipment is gratifying, custom fitting clubs to others’ individual swings is a level of personalization that both you and they will greatly appreciate.
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