MyGolfSpy Labs – The Iron Fitting Study

Written By: Erik Henrikson, Ph.D.

Iron Fitting

PING’s custom-fitting history dates back to the 1960’s when founder Karsten Solheim helped pioneer the concept by helping PGA Tour professionals calibrate their equipment to fit their size and swing tendencies. Using a player’s favorite club as a starting point, he would fine-tune the loft and lie of every iron to give each professional a perfectly matched set of irons. Karsten realized the vast majority of golfers were using equipment that was purchased “off the rack” without any consideration given to their biomechanical characteristics or swing tendencies. He then set out to research and develop a robust fitting process and system to help all golfers play their best. The first PING custom fitting system debuted in the early 1970’s, offering golfers a simple and effective way to match a set of clubs to each individual.

Nowadays any golfer has the opportunity to be fit for their next set of irons, or even retro-fit their current set. Technology continues to advance the industry’s understanding of how and why particular configurations of clubs work best for a particular individual, and expand the range of environments in which a high quality club fitting can take place. According to the 2015 Datatech fitting survey, 4 out of 5 golfers plan to be fit for their next set of irons. So how does one know whether they are getting a quality fitting and can walk away with confidence when they get fit for their next set of irons? The purpose of this article is to equip golfers to get the most out of an iron fitting and demonstrate the benefits of a custom iron fitting.

Things to Look for During an Iron Fitting

Conversation: The first goal of a well-trained fitter is to understand the golfer they are in the process of fitting. As a golfer, you should be asked a variety of questions about your game, strengths and weaknesses, preferences, and ambitions. As you are trying various club combinations, you should also be solicited for feedback, which gives the fitter an understanding of what you are feeling and experiencing.  If the fitter is looking at his shoes the entire time, it is time to find another fitter!

Bring current clubs: One of the best ways to gauge the benefits of a fitting is to directly compare results to your current set. If possible, always bring in your current set to provide a baseline for measuring performance improvements.

Pay attention to what is added to your club: In some environments, different items such as tapes, tags, or coverings may be added to the club to protect them from damage and/or theft. In most cases these things may have negligible effect on performance, but is some cases (such as some kinds of tape covering the face) they can have a significant effect on performance.

Ball flight: Most fitting environments have a way to track and record the flight of the ball using a launch monitor, which provides an easy and objective way to evaluate performance. A quality fitting is definitely possible without a launch monitor, but a launch monitor definitely adds extra value.

Grouping of shots: During a fitting, the temptation is to be drawn to that single, pure shot that went farther and felt better than any shot you have ever hit. Although this may give an indication of what the perfect shot with a given club feels like, it may not be a good representation of the performance you would see on the course. One of the defining characteristics that trends with handicap is consistency. Generally, the lower a player’s handicap, the more consistent they are shot-to-shot. So in addition to those single shots, pay attention to groups of shots. What iron option provides the tightest grouping? Tighter groupings lead to lower scores!

Ball Speed: Some fitters may use a value called smash factor to determine the “efficiency” of an iron. Smash factor is calculated by dividing the ball speed by the club head speed. So the higher the smash factor, the more ball speed you are getting for a given club head speed. The values will typically fall between 1.3 and 1.4 for a 7-iron. Although the idea of smash factor has its place, focus on ball speed. If you are trying to get more distance out of your irons, maximizing this value should be your ultimate goal. There are situations where even though the smash factor is higher, ball speed may be lower.

Pay attention to what fitting elements are addressed: There are a number of different elements that contribute to different configurations in a set of irons. The effect that each of them can have is varied, but there are some “close-handed” elements that should be discussed and addressed as part of a complete iron fitting. The next section of this article will address some of these elements.

Fitting Elements

Most iron fittings will center around the performance of either a 6-iron or 7-iron, and there are a number of different factors that can influence the performance a golfer even when looking at this single club. Below are a number of different elements that can influence performance and feel, and should be discussed during a fitting.

Model

Most OEMs offer a variety of iron models, ranging from compact, players’ irons to oversized models. During the interview, the fitter will gain insight regarding the model best-suited for that player, as well as his or her priorities for performance, feel, and appearance. The choice in model is one of the biggest levers in the iron fitting process. The size, center-of-gravity (CG) location, offset, and structural design can have a significant impact on the launch angle, ball speed, forgiveness, and workability of an iron.

Depending on the player’s ability, the fitter may recommend a more forgiving or more workable model to optimize control.  In general, lower handicap players will gravitate toward more compact irons that provide the golfer with a greater ability to maneuver the club in order to create a diverse range of trajectories and shot shapes. Others will perform optimally with generally larger club heads which provide ample forgiveness, leading to consistent ball flight patterns.

The percentage of golfers who fit into the different models of iron that PING offers can be extracted from PING’s nFlight software by mining the data from thousands of recorded fittings. The chart below highlights the range of models that golfers are fitting into. The Game Improvement irons are the most popular model. These are mid to oversized irons designed to provide extreme forgiveness, while maintaining workability.  Even though the these game improvement irons  fit a large fraction of golfer’s, there are a number of other models that players can find themselves performing best with depending on their aspirations and ability. A good fitting will help identify which model is best suited for your game.

Lie and Length

Lie angle is the measurement of the angle between the sole of the club and the centerline of the shaft. Establishing the most effective lie angle is a very important part of the fitting process as it can have a significant influence on shot trajectory and shape. Most irons can be custom fit to different lie angles to fit players of varying sizes, swing tendencies and ball-flight preferences. Length goes hand-in-hand with lie, as the two can influence one another. The reason lie angle can influence shot shape is that when a lofted club is delivered with the toe-up or toe-down, the face will be effectively closed or open.

In general, one of the biggest factors in determining what lie angle and length is best suited for particular golfers are their biomechanical characteristics.  A golfer’s height and the length of their arms can be great indicators as to what lie and length specs will work best for them. An example of a method that connects these biomechanical characteristics to a recommendation for lie and length is the PING Color Code Chart. A chart like this may be used to approximate the correct fit initially, allowing the fitter to build a club with that recommended length and lie (and an initial shaft recommendation) to try. The fitter will then refine and confirm the lie and length through a combination of lie board or marked ball analysis and ball flight analysis.

Through PING’s nFlight software, a snapshot of the various combinations of lie and length that golfers are being fit for can be obtained. The charts above and below highlight the wide range of values that produce the best performance for the general golfing population. As you can see, the most popular lie angle (which for PING is designated by a color code) is yellow. Even though it is the most popular, it only makes up 15% of the population. That means there is only, at most, a 15% chance the set up irons on the rack will be perfect for your size and swing. The similar distribution for length can be obtained, and is also shown below.

Shaft

There are a huge number of choices when it comes to shaft fitting. Not only are there differences in shaft type (steel vs. graphite), but various combinations of shaft characteristics such as weight, flex, and torque. Ultimately these different shaft properties can not only have a big effect on how an iron feels as it is swung and as it impacts the ball, but also can influence the trajectory that can be achieved with a given model.

Typically fitters will base an initial shaft recommendation on how fast a player swings or how far they hit the ball. In general, club head speed would be the best indicator since distance can be greatly influenced by player perception and quality of contact. Although there are a number of other factors (e.g. tempo, transition, impact position, etc) that may influence shaft recommendations, club head speed is a great starting point.

The fitter may use club head speed and possibly some other factors to choose some shafts to try. As you try different shaft options, the fitter should be asking for some feedback about the feel (flex, weight, impact) and performance of the different shaft options, as well as evaluate how each shaft is affecting ball flight. Looking at the distribution of different flexes and shaft types that golfer’s fit into, it is clear there is a pretty good spread of flex (R, S, etc) and type (steel vs. graphite).

As a golfer being fit, resist the urge to look at the shaft flex code (R, X, S, etc.) during this process.  Unfortunately there are no true industry standards when it comes to these labels. As a result there are some shafts labeled Regular that are in reality quite stiff, and shafts labelled X-Stiff that are quite flexible. PING characterizes each shaft that it offers, measuring a playable flex. Comparing shafts on a chart like the one shown here, it is clear that there is plenty of overlap between shafts labeled with a particular flex value.  As a result, it is best to not know during the shaft fitting process what you are hitting in an effort to not unfairly influence your perception of the results.

Part II

This is only Part I of our iron fitting study. Be sure to read part II where we take a closer look at additional fitting elements and provide you with data that reveals the quantitative benefits of custom fitting.

Read Part II Now.