Iron Fitting

Probably one of the easiest to fit categories is irons. If you already read through the Chapter 7: Clubhead Geometry in Pictures (Irons and Wedges), you will have good solid foundation of what we are going to go over and only a matter of tying everything together. When we talk about the irons, we are referring to the thin, elongated clubs in the bag with the numbers 3 through 9 engraved somewhere on the golf club head. The #1 and #2-iron are all but a relic of the past and the 3-irons is about to follow as few brand new irons (other than player’s irons) are still available. Golf iron sets will have a minimum of at least one matching wedge or possibly as many as 4, but we will reserve talking about those when we tackle the Wedge Fitting chapter next. We will also try to put the golf club iron fitting process in the best possible order.

Beginning the Process of Fitting for Irons

Where and how will you be conducting the fitting?

One important consideration is where would you conduct your iron golf club fitting? Every shop is different. Some shops will operate in a retail environment where the customer is only able to hit the ball into a net with the aid of a launch monitor, swing analyzer or simulator. Conversely the fitting may be conducted outdoors at a range with or without the assistance of computerized equipment. Lastly, the fitting could be all done over the phone or internet as an on-line transaction or surprise gift for someone. In all these situations, how the fitting is performed will vary.

Personal Interview and Specification Check

You would want to conduct the personal interview if you were fitting for the golf irons separately and you had not already completed this step when fitting any of the other categories previously. For a review of the personal interview process and a list of possible questions, please refer to Chapter 3. Except for golfers brand new to the game, I would strongly suggest the customer have their current irons so you can inspect wear patterns on the clubs and gather as much information by measuring their specifications if at least a single or their favorite iron.

If the player comes to you with a right handed club, that will obviously mean they will need right handed models. But for a golfer brand new to the game, you may need to ask or evaluate them for handiness by having them hit a few balls. The main reason for asking handiness first is if they are left-handed, there will be far fewer options to choose from.

How Irons are Fit Today

Take a page and look at the efficiency of major manufacturers fitting carts. What will you see? It will be a collection of mid-irons such as a number 6 or 7-iron (but not both) and a selection of gripped shafts onto an adapter system where they can be easily be interchanged to cut down on inventory, make the fitting system portable and more effective at the same time. Once a single iron is fitted, all the other irons will use the same shaft, flex, grip, grip size, length and lie relative to a standard.

The other scenario is how irons were often fitted a decade ago where again a mid-iron is chosen. Then each one is installed onto the same length shaft, same flex and grip size and the customer can hit them to see how golf club heads reacts differently from another. This is fine, but this method does not show the immediate interaction between the head and shaft as most modern fittings are conducted.

Lastly, iron fitting could be in a static fitting situation as the head is selected by picking them out of a box or display of sample clubheads so the customer can hold them in their hand and see and feel it as the fitter explains the differences amongst them. The alternative is looking through a catalog or surfing through the irons listed on a particular manufacturer’s or clubmaker’s website to read the descriptions, reviews and examine the specifications to see which type may benefit or interest the customer.

Choose the Set Make Up

It used to be customary a golfer would purchase the full allotment of irons to have a “matched set.”  But those days are gladly long gone, and the customer can often pick and choose what they feel most confident hitting with.  The advent and popularity of hybrids, customers now opt to start looking at irons starting with the number 4, 5 and 6 engraved on them. I call this the longest iron rule. Ask the customer what the longest iron is they feel they can honestly hit decently. It does not need to be “knock down the pin” accuracy, but at least the sensation they have a fighting chance to hit the green from the middle of a flat fairway or tee box. Let us say their response is a #6-iron. Ask them if they would feel better off hitting a #5-iron or a #5-hybrid if they had their druthers. If they say 5-iron, ask the same question, but this time the option of a #4-iron or #4-hybrid. You will find out quickly what the player really wants to hit.

The argument why players typically opt for the traditional 3-PW set is for resale value. My standard argument is you are not investing into a set of clubs just to sell at a later date. Rather these are clubs that you will get plenty good use of and hopefully bring with them good memories that will last a lifetime. Plus, the resell value of used clubs is going to be spotty at best. Just think in a few years from now are players going to even want the #3 or #4-iron in a set and only offer money for the #5-iron and down.

iron set make up comprising of a 4-PWiron set make up comprising of a 4-PW

Determine Iron’s Level of Forgiveness

One of the very first considerations is clubhead selection, which gives us the proper level of forgiveness. That is, does the player need all the help they can get, a lot of help or not much help at all? To help define the level of forgiveness we can break down irons into 3 basic categories: player’s irons, game-improvement irons, and super game-improvement irons.

Player’s irons are for better ball strikers or low handicap players who request a specific look and possess limited forgiveness to allow them to work the ball when needed. These constitute your blade-style irons, more compact cavity back irons, or compact hollow-bodied irons with reduced amounts of offset. Each manufacturer will prominently feature at least one model in this category despite the limited pool of players who will be able to use them effectively.

Consumers are exposed the most often to the game-improvement iron category. These will all feature a cavity back for perimeter weighting and most will have an undercut cavity as well to position the weight even lower and more rearward. The amount of offset built into the design will be greater and so too with their blade lengths than the player’s irons. Offerings in this category will be manufactured from a single material throughout with a greater abundance of styles to choose from even in left hand.

The super game-improvement category comprises your multi-material irons such as those with maraging steel or titanium as well as any tungsten weighting used for greater weight redistribution around the head for the utmost in forgiveness on off-center shots. They will be amongst your most expensive irons available.

If the player is content on what iron they are presently using and simply wants retrofitted by resizing, reshafting, or regripping their golf clubs, then is one less step that must be completed. However, if the player is using an iron that is designed for a better skill level than what they are presently, you may want to plant a seed and explain the benefits of choosing from a different category. After all if the player is hitting all over the face, there is no guarantee a change in the shaft, grip or length will help.

Factor Iron Specifications for Direction

When discussing irons, one term you never hear of is face angle, although it can be engineered into an iron design. This is primarily because the sole on an iron is relative narrow and does not normally sole itself into one face angle as say a driver will. Therefore the golfer will square (or attempt to square) the face toward their target. So there are a couple of key parameters which highly influence direction. One is offset and the other is lie.

The Myth of Offset

Golfers who are new to the game will find many confusing terms associated with golf clubs. Not only that but some of those explanations are inaccurate as well. One such example is offset or the distance between the leading edge of the hosel and the leading edge of the face. Many times I see the explanation that offset shifts the center of gravity further back in the head resulting into a higher ball flight. I want to dispel this myth and help those understand the function of offset better.

First, it is difficult to truly tell what offset does by itself. Typically heads with reduced, little or no offset tend to be designed quite differently from irons with additional offset. Increased offset irons are designed as game-improvement clubs, many of which have longer blade lengths, more upright lies, wider soles and shorter hosels creating totally different inertial properties compared to reduced offset player’s irons. In this case, there are too many other parameters that have changed to honestly access what effect offset itself has on ball flight.

I am fortunate to have accumulated a lot of different irons over the years. One model was a Ping Eye II style iron that every manufacturer created a design variation back in the late 1980’s and early ‘90s. Dynacraft’s version was called the “4140”. This was a progressive offset, cavity back design with the 5-iron featuring 3.5mm offset. Dynacraft also tooled up another design called the On-Line. This head was made from virtually the same mold as the size, shape and profile were replicated. The only difference was the On-Line featured no offset at all. Finally, two heads so similar to one another that the effect of offset could honestly be tested.

To understand how small a difference this really is, look at the offset value. In metric, 3.5mm might seem like a lot, but in imperial measurements this amounts to only 0.138” or just over 1/8th of an inch. With these two clubs in hand, they were measured very carefully to make sure they had the exact loft and lie, if not they would have been adjusted. As luck would have it, both measured 28° loft and 60° lie. Again these were older irons as reflected by the flatter lie and weaker loft angles compared to what you find today. Each clubhead was built as a demo with the same shaft, shaft weight (within the gram), frequency, grip weight, while the shaft were carefully cut on a cutting jig to ensure the exact amount was trimmed from the tip and butt and then assembled to the exact same length and swing weight.

diagram of two irons, left is a non-offset iron, right an offset irondiagram of two irons, left is a non-offset iron, right an offset iron

What happened when these two clubs are hit side by side at the range? Let us look at the sole and see if there is anything we can discern from the wear patterns. First, the impacts are equally out toward the toe of the sole indicating the lie may not be correct. This should come as no surprise, after all they are equal because the measured lie, blade length, shaft, shaft flex and length are all identical. 

However, one of the two major differences occur in the wear pattern on the sole in relationship from the leading and trailing edges of the respective club. The club on the left is our “offset” model. The black electrical tape is worn off of the sole very close to the leading wedge. The non-offset iron is clearly more centered showing the angle of attack is dissimilar. As a review, in the diagram below shows the three scenarios for angle of attack with an iron.

sole impact using black electrical tape to see difference between hitting a non-offset iron versus an offset ironsole impact using black electrical tape to see difference between hitting a non-offset iron versus an offset iron

One plausible explanation is the change of offset could have affected the ball position in the stance. Let us say a golfer is at the driving range hitting off the grass or a mat. The golfer drops or rakes a ball somewhere on the ground in front of them. From there he or she attempts to align themselves and the clubface to the ball and their target. Remember a lot of misdirected shots are a direct byproduct of being misaligned toward the target.

The ball will be a positioned somewhere in relationship between the player’s front and back feet. By varying ball position can easily change the player’s perspective of alignment. The further back the ball is positioned it is more likely the player is to create a steeper angle of attack, not to mention the clubhead could be coming more from inside to out with a more open face as the club has not bottomed out in the swing arc.

diagram of 3 irons, one with hitting the ball on the upswing, one level and one on the downswing and where contact occurs on the solediagram of 3 irons, one with hitting the ball on the upswing, one level and one on the downswing and where contact occurs on the sole

Another reason why the offset affected sole impact is the additional offset delays impact for a split second and here is the reason why. On the left are two irons superimposed using the shaft as the common reference point. Notice the iron toe profile highlighted in black as this is our reduced offset iron. It is just contacting the ball, while the offset iron is several millimeters behind (or 3.5mm in our case). By delaying impact the 3.5mm the face will have traveled longer in the swing arc making the face angle a fraction of a degree more closed (nearly a 0.25º). This is one of the reasons that an offset iron is recommended for higher handicap golfers who are more prone to fading their irons.

diagram of two scenarios hitting a ball with non-offset and an offset iron, one club arrives first, the other one is hit with a shallow angle of attackdiagram of two scenarios hitting a ball with non-offset and an offset iron, one club arrives first, the other one is hit with a shallow angle of attack

But there is probably more than that which meets the eyes. With the non-offset iron, the hands must have been positioned not as far forward causing a shallower angle of attack for the sole marking to occur as they did. The illustration on the right depicts this possibility. Another byproduct of an increased angle of attack will be a change in the initial trajectory as well as the spin rate.

The other major difference in the sole impact was the brush marks left on the black electrical tape from impact with the lie board. The non-offset iron showed a square path while the offset model clearly showed an open face from the aft ball position. Face angle at impact also factors into trajectory; a more open face creating a higher trajectory. Lastly, face angle controls any slice (open) or hook (closed) spin. All of this from a small change of offset.

I personally noticed the ball flight was higher with the non-offset iron. There has been much debate over the years on the effect of offset. I am sure that I will hear arguments from fellow colleagues and golfers who will read this and make a judgment based upon their past experiences. My contention is the clubhead design, aside from the actual offset, may be the reason for their response. I simply wanted to conduct a scientific approach to limit all other variables as physically possible to assess only one parameter which was the offset.

So if you hear a golfer saying they hit the ball higher with an offset head or lower, they both could be correct as the player’s perception of alignment can easily change. This is the reason why the club fitter should test for offset by at least having two models of similar size, lie, length, shaft, etc. except one has far more offset than the other in their demo program to see how their customer reacts.

For most golfers, the tendency with an offset club would yield a ball flight that will go further left than a similar club with reduced offset (this for a RH golfer). To understand why can be explained by the position of the center of gravity.

The center of gravity of our non-offset club is further behind the face of the club. The reason for this is the hosel contributes to a considerable percentage of the overall clubhead weight. The clubhead with more offset shifts the weight of the hosel forward and the CG toward the face rather than backwards. However, the center of gravity in relationship to the centerline axis of the shaft is further back in the offset head. This is what helps the clubface assist is closing the face. A rearward center of gravity from the shaft’s axis increases the gravity angle, therefore naturally closing the face.

diagram of two irons and their gravity angle, left is offset iron with greater angle than non-offset iron on the rightdiagram of two irons and their gravity angle, left is offset iron with greater angle than non-offset iron on the right

For golfers that tend to fade or slice their irons, avoid heads which are long from heel-to-toe and reduced offset. The longer blade length will push the CG further from the hosel and coupled with the reduced offset create a more fade-biased combination as this will reduce the gravity angle. While the longer blade length may give the player more confidence and potentially create a higher MOI or more forgiving club on off-center shots, it will do little in the way of helping that golfer square up the clubface at impact.

Fitting for Iron Length

Once we have a general idea of what level of clubhead forgiveness we need, we can start looking at what will help the player hit the ball toward their intended target line and at a height or trajectory that will provide for distance as well as stopping power once it hits the green. A good starting point is the length as some of the other parameter will start to have a domino effect.

If a club fitter has at their disposal an interchangeable head and shaft system, this will allow them to able to try out different combinations quickly. If this is the case, I would encourage a few of the gripped and shafted adapters to be dedicated solely to length such as a standard length and 1” longer than that. The player could grip down ½” on the 1” longer club to simulate a ½” longer club. They can do just the same on the standard length to simulate ½” shorter than standard. With two clubs, we can simulate 4 different lengths. I might suggest adding a ladies standard length and 1” shorter for petite sized ladies. The best part is the men’s and standard ladies are probably already part of your demos.

Even if you did not have an interchangeable head and shaft system, offering just a few different length clubs on the same type of head (preferably a game-improvement model) is all that may be necessary to test for length. Know the demographics of your customers as well. If you cater to more of a senior crowd, then the length test clubs should be senior or whatever flex you sell the most of to your clients. And while a ladies +1” may be the same length and a men’s standard, recognize the flex of the men’s might be too stiff (and possibly too heavy) for a female customer to hit.

Using impact spray or decals on the face, you can have the player hit balls out on the range or into a net and find what length seems to fit them best. It will be obvious as the clustering on the face will be the tightest and hopefully centrally located in the scoreline area. If impacts are made out consistently in the toe or heel, that is fine as we have yet to talk about lie. You can use the height and wrist-to-floor charts if you wanted a reference point from which to start. Do not ignore your customer’s comments either regarding what they feel most comfortable with if it is a toss-up between two lengths.

Comparing Single Length Irons to Variable Length Irons

Single or one length irons are an option available to club fitters and their customers alike. The purpose of having all the irons the same length is providing a repeatable swing for all the irons in the set. Instead of 7 or 8 different ball positions and stances to learn, it simplifies it to one – generally to the length of a 7-iron.

Most golfers struggle hitting their long irons, and this is where a set of single length irons shine allowing for more solidness of contact on the face. The downside is the highest lofted irons and wedges are longer-than-normal, which may makes it harder to create finesse shots around the green or in the bunker. If you offer single length irons in your shop, make sure to have a sample of a 4 iron, 7 iron and pitching in both types of set so your customer can compared to see which one they prefer.

If you have an iron set that is designed for a progressive length iron set, can you modify them to be a single length iron? The answer is no. In order to creates a functional single length iron set, each club head should be of the same head weight and lie angle. In addition, the lofts may need a greater separation between adjacent clubs in order to maintain normal distance gapping as the swing speed will not vary due to clubs being the same lengths. Examples can be found in the following charts.

Progressive Length Iron Set Specs

Club Loft Lie Head Weight Length
4 iron 20° 60.25° 249 g 38.5"
5 iron 23° 61° 256 g 38"
6 iron 26° 61.75° 263 g 37.5"
7 iron 30° 62.5° 270 g 37"
8 iron 34.5° 63° 277 g 36.5"
9 iron 39° 63.5° 284 g 36"
PW 44° 64° 291 g 35.5"
GW 49° 64° 291 g 35.5"
SW 54° 64° 298 g 35.25"


Single Length Iron Set Specs

Club Loft Lie Head Weight Length
4 iron 20° 62.5° 270 g 37"
5 iron 25° 62.5° 270 g 37"
6 iron 30° 62.5° 270 g 37"
7 iron 35° 62.5° 270 g 37"
8 iron 39° 62.5° 270 g 37"
9 iron 43° 62.5° 270 g 37"
PW 47° 62.5° 270 g 37"
GW 51° 62.5° 270 g 37"
SW 55° 62.5° 270 g 37"


Determine Length in a Static Fitting Situation

Base the length on their height and any information they provided during the personal interview process. This may require a quick trip to the internet to find what length the manufacturer originally built the club too depending on how old their irons are. The reason for this is most end consumers do not know the proper technique to measure the length of their own clubs.

Make sure to ask if their current clubs were custom made or custom ordered to a length other than standard or if they had a recent fitting. While not all manufacturers use the same standard, at least the iron category has the smallest length deviation from one manufacturer to the next.

Ask if they hit a lot of fat shots or tend to choke or grip down on the club to hit it solidly. If so, shorter clubs than they have now are in order. If possible, see if the customer can tell you how much distance there is between heel of their upper hand and the end of the grip when choking down on the club.

Iron Length by Height Chart

 Height Height (inches) Height (centimeters) Length Relative to Men's Standard
4' 7" 55" 140 cm 2 1/2" under standard
4' 10" 58" 147 cm 2" under standard
5' 1" 61" 155 cm 1 1/2" under standard
5' 4" 64" 163 cm 1" under standard
5' 7" 67" 170 cm 1/2" under standard
5' 10" 70" 178 cm Standard
6' 1" 73" 185 cm 1/2" over standard
6' 4" 76" 193 cm 1" over standard
6' 7" 79" 201 cm 1 1/2" over standard
6' 10" 82" 208 cm 2" over standard
7' 1" 85" 216 cm 2 1/2" over standard


Fitting for Iron Lie

Fitting for the correct lie is especially important when it comes to the irons. Not only can it improve direction but solidness of contact too. For a full discussion, review the Lie chapter. Fitting for lie can be done at the same time as you test for length or even clubhead design with your demo clubs.  Use a lie board in combination with some sort of impact label for the sole. While the marks on the sole may indicate a malady between the player and lie of the club, take note of the direction of the ball as that will be the overriding factor whether the lie is too upright or flat. Fitting is best outdoors for this very reason.

Pay close attention to manufacturing tolerances (typically +/- 1°). The following chart shows a possibility in lie progression in a set, yet each of the irons is well within the tolerance range. As you can clearly see it is not a nice even transition from one iron to the next. With a lie/loft machine the clubmaker can adjust the set where it will flow better.

Iron Club Lie Spec Actual Lie
3 iron 59° 60°
4 iron 59.75° 59°
5 iron 60.5° 61.5°
6 iron 61.25° 61.25°
7 iron 62° 61°
8 iron 62.75° 63.75°
9 iron 63.5° 63.5°


Also note if you need to bend the irons 2° upright from the manufacturer’s lie spec, some of the irons you may have to bend 3° to achieve a net 2° change while others could be as little as a 1° alteration. Try to limit any marring on brand new irons heads to a minimum by using a high quality bending bar, securing the head well and using the proper technique. Your component suppliers may offer a lie bending service for a nominal fee.

Iron fitting could be as simple a adjusting the player’s current set of irons to the proper lie that will put them on the straight and narrow path to a better score.

a person bending the lie of an iron with a bending bar and loft/lie machinea person bending the lie of an iron with a bending bar and loft/lie machine

Fitting for Iron Loft

The current trend in golf is toward stronger (reduced) lofted irons as they are geared for more distance. Part of any manufacturer’s decision on whether the lofts will be strengthened should be based solely on the position of the center of gravity. If it is extremely low via a very shallow profile, the usage of multi-materials, or pairing with a high launching shaft, stronger lofts are justified to help maintain a normal initial launch angle.

However clubmakers could effectively reduce the loft of the majority of irons on the market by a couple of degrees with a lie/loft machine.  One word of warning, this will provide little in the way of “extra distance.”  For instance if a player is hitting their irons with a 10 yard spread between each iron, then bending all the lofts stronger by 2° is only going to provide that player with at most 5 additional yards. After all, the gap in loft from one iron to the next is generally 3-5 degrees.

Make sure when changing lofts it is performed for the sole purpose to spread out the distance gaps better between consecutive clubs. With manufacturing tolerances of +/- 1°, it could be possible that a set might have some irons with as little as 1° difference in loft and 5 or 6° between other. This chart shows a common set, yet each of the irons is again well within the tolerance range. By the clubmaker checking (at the same time lie is accomplished) and bending appropriately can these possible situations be resolved.

Iron Club Loft Spec Actual Loft
3 iron 20° 21°
4 iron 23° 22°
5 iron 26° 27°
6 iron 29° 29°
7 iron 33° 34°
8 iron 37° 36°
9 iron 41° 42°


Even for players using their own irons and needing a new shaft, grip or club lengthened or shortened would be a good opportunity for an experienced club fitter to check the specs. Over time hitting tree roots or pounding the ground with irons made from soft material (such as forgings) could make the loft (and lie) go out of whack.

Remember the affect that bending the lofts stronger or weaker can do to the sole or bounce angle of the club. By reducing the loft, the bounce angle reduces and lowers the leading edge of the face. This could create an unsolid feeling at impact for a golfer with a very steep angle of attack as the leading edge may dig into the ground. Conversely, if we wanted to weaken or increase the loft then this will make the contact point on the sole with the ground shift rearward and raise the leading edge higher up in the air potentially causing a player with a sweeping or scooping type swing to blade the ball.

diagram illustrating the effect of bounce and where contact will be made on the sole when bending iron 2° strong and weakdiagram illustrating the effect of bounce and where contact will be made on the sole when bending iron 2° strong and weak

If a player struggles to get the ball airborne, look closely at the lofts as you might be able to find certain models with weaker lofts to launch the ball higher. If not, when the player does hit the green from a distance, the ball may release rather than “checking up” and completely roll off the green. It may also help to further assist the player by seeking out a head design with a shallower face, shorter hosel and/or wider sole as all those can help to lower the center of gravity and toward a higher ball flight.

Iron Shaft Fitting

Even if you fitted your customer earlier for a driver with a flexible tipped S-flex does not necessarily mean that the irons will be matched with the same type or even flex of shaft. Often the woods, including hybrids will be graphite (for distance) the irons are often steel-shafted (for control). In other cases the shaft choice is steel from an economical concern as there are generally several irons to purchase. Therefore I treat iron shaft fitting separately from the woods.

Secondly, we assume that a player will swing the same way with their driver as they do the rest of the clubs. Well, do not assume anything. I once had a player swing his driver 103 mph, but only swung his 5-iron 69 mph (or 67% of driver speed). Now if you are considering what is standard, that is another problem. Not all swing speed devices measure the same with the irons like they generally do with the driver. Part of that can be explained on where the swing speed is measured at as all golfers will decelerate at impact. If the device measures the 6-8” before impact versus readings based on averages of the lower third of their swing, the latter will often be higher. This is why shaft manufacturers will suggest their iron fitting based on a driver’s speed rather than a certain iron (like a #5, 6 or 7) that are used to fit players as there is no consensus there either.

I was able to find data recorded with a Trackman launch monitor for PGA and LPGA players. Their 5-iron speed was @ 84% of their driver speed on average. Using the same percentages as the tour players, we could extrapolate the following chart. The 6-iron was added as many club fitters are using a 6-iron rather than a 5-iron in their fittings

Driver Speed Compared to #5 and 6 Iron


5 Iron

6 Iron

60 50 49
65 55 53
70 59 57
75 63 62
80 67 66
85 71 70
90 76 74
95 80 78
100 84 82
105 88 86
110 92 90



Driver Distance (yards)

5 iron Distance

6 iron Distance

60 153 yds 110 yds 104 yds
65 163 yds 119 yds 113 yds
70 179 yds 129 yds 121 yds
75 191 yds 138 yds 130 yds
80 204 yds 147 yds 139 yds
85 217 yds 156 yds 147 yds
90 230 yds 165 yds 156 yds
95 242 yds 174 yds 165 yds
100 255 yds 184 yds 173 yds
105 268 yds 193 yds 182 yds
110 281 yds 202 yds 191 yds


There is also proportionality when it comes to the distances between a driver and #5-iron. For example, a #5-iron is likely to go @ 72.5% of the overall distance as the player’s driver. But certain golfers are more confident with their irons than their driver or vice versa so that proportionality is not always the same. As in my case, the player was hitting the driver @ 255 yards but only hitting his 5-iron 150 yards. He should have been closer to 184 yards based on the averages. Well come to find out he was fit a few years before with an A or senior flex steel iron shafts in which he liked the feel of. To control the direction, he had a much slower swing tempo than he did for his driver. In the end, we retro-fitted him with a much stiffer shaft that allowed him to swing as aggressively as he did the driver. It resulted into a 15 mph increase and closer to a 35 yard gain using his existing heads at their same length.

Any time you are measuring the player’s swing speed or estimating it from the distance they hit the ball you will want to also examine the length of the player’s swing (3/4 vs. a full swing) and their tempo (fast, moderate, or slow) as these two items factor into the final flex the customer needs. Remember, the shorter the swing and/or the faster the tempo, the stiffer (and possibly heavier) the shaft should be given the same swing speed. You can look at the conversation factors in the Shaft Fitting chapter for the length of the swing and the player’s tempo and apply it to the player’s swing speed to choose an appropriate swing speed range from which to select the shafts.

Performance Based Shaft Fitting

If you have various shafts installed into a selection of iron models or have an interchangeable clubhead and shaft demo program, you can use that now to find a shaft which produces the best results regardless of what their swing speed is. This is called performance-based fitting and eliminates the need to check swing speed or even factor the swing tempo into the equation. You might still use the tempo, speed or distances hit as a guideline to start your fitting, but by handing the player stiffer or more flexible shafts from your demo program you can tell right away what stiffness range the player needs. If not, you will have to reason what type of parameters I should be looking for to fit my customer.

Tip Size

Iron shafts are usually available in either of one of two sizes.  One is 0.370” parallel tip and the other is 0.355” taper tip. The club fitter will need to pay close attention the to the tip size if retrofitting an existing set of irons with a new shaft because there are far fewer choices in taper tip especially if the customer needs a softer flex (ladies or senior) or requesting graphite shafts. If that were the case it is possible to bore out the irons to accommodate 0.370” parallel tip shafts, which are more plentiful.

Shaft Weight

Irons are generally purchased for their accuracy more so than their distance. That is why it is commonplace to see heavier shafts installed into an iron than the driver, fairway woods and hybrids. However, for slower swinging golfers may find the weight of the iron shaft can be the same as their longer clubs. With reduced speed, even if the ball is offline, it will not go as far offline as much as someone stronger with the same amount error at impact. Plus, the reduction in weight may help to produce a lighter and potentially longer club for more leverage and greater distance.

Realize that weight is weight. There are graphite shafts that are just as heavy as some of the heavier steel shafts and there are steel shafts that weight close to 80g and in the range of many graphite shafts. If you are wondering why anyone would want a graphite shaft as heavy as a steel shaft it is often for vibration dampening. The rule of thumb is if a player has a faster speed, faster tempo, or abbreviated swing that a heavier weight will help to pace out the player’s swing and usually provide increased accuracy over a lighter weight shaft.

Shaft Flex

When we mention shaft flex, we are going beyond the generic letter code designations (L, A, R, S and X), but rather the frequency of the shaft as there is no industry standards. For instance, some R-flex shafts are weaker and toward or in the A-flex range while others can be as stiff as S-flex shafts. This is why the Dynamic Shaft Fitting Index (DSFI) was established. But it is important to look at the final frequency of the club only with similar weights are we shall see in our next parameter.

Tip Stiffness and Shot Trajectory

The shaft selection process can also assist in hitting the ball higher or lower. You may want to consult the ball flight descriptions from the manufacturer website or component catalogs. These will usually be listed as high launch, mid launch, or low launch, but you may see other descriptions such as mid-low or mid-high too. These descriptions are often based on human or robot data collected to see how the shafts they sell launch relative to one another. However, there is no universally adopted method to compare trajectories across the board for all manufacturers.

In years past, the trajectory was inferred by the bend or kick point of the shaft or the point of maximum bending. The trajectory is a function of several factors, one of which is the flex. As we saw in the Shaft chapter, the lighter weight steel shafts often have a lower frequency in the same given flex as there is less material to resist bending. This is why most of the very lightweight steel shafts are all high launching even though the bend or kick point may be no different than models described as mid or high bend point.

Most of your heavier weight steel shafts are listed as mid or low launching. There are exceptions, but very rare to see a heavier weight shaft that is truly high launching.  That requires the shaft to have an extremely long parallel tip section. But do not expect the ball flight to be considerably different if the shaft weight and flex (actual frequency) are similar. It takes a pretty large change in those two parameters to alter the ball flight.

A softer tipped shaft or one labeled as high launching may be more prudent for a player prone to pushing or fading their irons as a softer tip section may help close the face rather than hit the ball higher. Conversely shafts that may be considered stiff tipped (low launching) may be preferred for players that pull or draw the ball as the stiffer tip will resist bending forward as much as a softer tip shaft prior to impact.

Shaft Torque

I would pay very little attention to the shaft torque in an iron shaft. On steel shafts it is not even listed by most manufacturers even though it does exist (@2°). Steel shaft manufacturers simply cannot independently control shaft torque as they can graphite or composite shafts.

The only exception I would make is for heavier composite shafts with a large torque listed as that would be an example of a fiberglass-laden model, which will often have a very flexible tip section and launch the ball higher (but not necessarily less accurate).

Demo Shafts

Whether you are using an interchangeable head and shaft program or simply making up the same mid iron (such as a 5, 6 or 7-iron) and assembling them with various shafts for your customers to hit, make sure not to duplicate them. Make sure each shaft that is in your demos has a unique set of weights, stiffness, and tip stiffness. This does not mean to go overboard with selections either. I doubt you will need a heavy weight steel shafted L or A flex iron shaft just the same you would not want an ultra-light X-flex graphite iron shaft.

If a player were using one of the demo clubs that felt a little light, you could always add weight onto the shaft (or into with a mid-weight) to simulate a heavier weight model. If the player felt the demo you handed him or her produced good results, but was a tad heavy, you can select a shaft with similar characteristics, albeit a little lighter.

Determine the Shaft in a Static Fitting Situation

One way to fit for shafts when a player is not capable of hitting various shafts and evaluating the results such as an internet fitting or surprise gift is to use the fitting charts by the shaft manufacturers or Hireko’s “Shaft Fitting Addendum” to “The Modern Guide to Shaft Fitting,” a companion books that contains thousands of shaft specifications that you will find of invaluable use in your custom club fitting and shaft selection work.

We recommend starting any shaft fitting session by recording the golfer’s average swing speed, tempo and length of swing and then refer to the procedural outline Charter 10: Shaft Fitting. After finding the player’s recommended swing speed range, one can narrow down the list of shaft choices based on ball flight, brand, cost, color, etc.

Grip and Grip Size

Take the time to fit your customer not only for grip style and brand that may be their favorite or chosen from your grip display, but also check they have the proper size. For a complete discussion of grips and grip sizing, please refer to the Grip Fitting chapter.

Remember the cause and effect of grip weight as some jumbo grips can be considerably heavier than others, plus you have lighter weight models available that can reduce the overall weight of the club and increase the heft of the club at the same time. Demo clubs are really the only way to test for this.

One quick word on grips is alignment. As mentioned earlier irons do not sole themselves like a wood as the player will attempt to align the face to the target. As an aid the player may use the logo of the grip to ensure that. However any misalignment of the grip will create a situation where the club may be aiming left or right of their target unbeknownst to the player.

I remember a good friend and fellow clubmaker that whenever he installed grips onto an iron with a lot of offset, they always looked (consistently) closed to me. If I installed the grip on the same set of iron, he would say they looked open. Another aspect of offset is the perception of alignment. I have also heard where the fitter instructed the assembler (if not themselves) to turn the grip one way or another to compensate for a flaw in the player’s swing. This is very tricky to do and make sure that it is uniform throughout the set.

Determine the Grip in a Static Fitting Situation

In cases when a player is not in your shop to demonstrate the different type of grips and sizing or capable of hitting various clubs and evaluating the results such as an internet fitting or surprise gift, use the grip sizing charts. Make sure to ask if the player has a favorite grip (or size) too. If the player’s hands sweat a lot or play in hot and humid conditions on a regular basis, know what types of grips you stock that would be the most beneficial.

Weight Distribution and Final Adjustments

If you are using an interchangeable club head and shaft system to fit your customer, you can add smaller amounts of weight to the iron to fine tune swing weight. If your demo clubs have holes cut into the butt ends of grip, you use any counterweighting system to see if alternative weighting may stimulate a difference in the comfort level and performance at the given length and shaft weight you fit for. It should only take a few swings by the golfer to see if counterweighting has any positive response. If not, you can rule it out and at least your customer had experimented with something few golfer ever do.

If you are not using an interchangeable club head and shaft system, you most likely will be fitting based on a myriad of demo clubs where you are isolating one parameter at a time (or none like in a static fitting situation). If that were the case, few of the specifications would be all on one club where you can fine tune or optimize swing weight or any alternative weighting for best results. By using the principles discussed in the length segment will often take care of producing a club that is too heavy or light.

Iron Fitting Summary

Once you have completed your iron fitting, it may off to fit the wedges before you begin to order and build the club(s) to those specifications. The total time to fit your customer will vary depending on how involved you want to get or just how badly they were fit before. It may be as simple as a new style grip and size or alterations to the length, lie and loft of their current irons. On the other hand, you might have a customer with a unique set of challenges that you have to go through every aspect of the fitting until you settle on what will help them hit more GIRs, which there is a direct correlation to lower scoring.

  • Start the longest iron with one that the player will have some confidence in and if they have any druthers consider replacing it with a hybrid.
  • Using an interchangeable club head and shaft system will make fitting irons not only more efficient from a cost and time point of view, but you will also see the interaction between the head and the shaft and how they work in unison.
  • Select an iron with the proper level of forgiveness based on the player’s ability at the time of fitting. If they prefer a player’s iron and their skill level is iffy at best, try to plant a seed and explain difference and then let them make the decision.
  • Reward a good shot and get the customer on the straight and narrow by choosing an iron with the proper amount of offset based on ball position and angle of attack and then adjust the lie accordingly to their posture and comfort level.
  • Select a shaft based on the way they swing their irons and not necessarily the way they swing the driver as it can differ. The shaft weight and stiffness will be key factors to control their timing and rhythm since accuracy is usually more important than distance other than those that have diminished strength. Those two factors will also control trajectory and spin too.
  • Select a shaft that matches the head style as the center of gravity of the head may be more complementary to certain shaft specifications.
  • Not only select a grip that is the proper style and size, buy also make sure the grip is properly aligned so the customer is aiming the club where it is supposed to be.
  • Check to see if alternative weighting or adjustments to swing weight can help fine-tune the club to the player’s natural swing as most golfers have not been exposed to these concepts.

Modern Guide to Golf Clubmaking

© 2024 Hireko Trading Co.,Inc.. All rights reserved, including the right to reprint or reproduction in whole or in any form.