Constant-Length Irons

Dave Tutelman  --  August 19, 2007
Updated  November 21, 2015

In the late 1990s, I did a brief computer study of constant-length irons; that is, all clubs in the set are the same length. In 2007, Bill Wade asked my opinion of constant-length iron sets, and I revisited the question. In 2015, Bryson DeChambeau won the US Amateur with a constant-length set of irons, and the topic got hot again. So here is the 2015 update.

This article compares the carry distance and trajectory of two design principles for irons -- conventional and single-length. This is the third time I have gone through the study over almost 20 years. Here is a synopsis of the studies:
  1. Original study -- mid-to-late 1990s. That is still around, more or less, in my tutorial on golf clubs.
  2. Second look -- 2007. I was asked by Bill Wade if there is anything new on the subject. What I found was a company that makes sets of these clubs (1 Iron Golf) and another that sells heads designed for such sets (My Ostrich Golf).
  3. Third look -- 2015. This year, Bryson DeChambeau won the US Amateur and the NCAA individual honors using a single-length set, and as I write he is doing very well at the Australian Masters. So interest is way up world-wide, hence this update. 
As of Fall 2015, here are the changes in the marketplace:
  • My Ostrich Golf is out of business, and the heads they sold are no longer available.
  • 1 Iron Golf is still truckin'; probably doing a land-office business due to DeChambeau.
  • Value Golf sells heads made for constant-length sets, as well as made-up sets using the head.
  • DeChambeau's irons were custom made for him by Edel Golf. They are known to be high-end customization specialists. But Grant Garrison posted to the Golf Teaching Professionals forum, "Bryson DeChambeau had his made by Edel Golf but they have no plans to offer them, telling me they take too much time and effort to build."
  • I know that the engineering department at Ping did a study in 2012-'13. But the results of that study are unpublished, and I don't know where they intend to go with it commercially.
I'm a technical guy, not marketing, but if the sudden demand for single-length iron sets proves to be robust we might see them from Edel (who already knows how), Ping (who understands what they do), and custom component shops like Wishon or Maltby. That is in addition to 1 Iron and Value Golf, who are already in the market.

This study is a little different from my years-ago study described in the "Length" chapter of my Design Notes. That study assumed a golfer skilled enough to swing a club properly over a wide range of swingweights -- as would have been required with the clubheads available at the time. If we were to build a constant-length set using standard clubheads with a 7-gram weight progression, which would have resulted in swingweights from B-7 to E-1 across the set (assuming the 7-iron was built to a fairly normal D-1). That is way too much to correct with lead tape and tip weights.

Instead, we are going to take advantage of the fact that today there are clubheads made specifically for single-length sets. We use clubs built to the specifications of a 7-iron, except for loft. Length, weight, lie angle, flex, etc are the same across the entire set. (Actually, I don't know of any work saying what the flex progression should be for a single-length set. I'm just assuming the shafts will be the same flex, for simplicity's sake.)

The table below shows the carry distances for several different sets of irons:
  1. A conventional set, with length increments of 1/2" per club.
  2. A constant-length set, with the same lofts as the conventional set.
  3. A constant-length set made with iMatch irons, which have a different loft makeup. The iMatch irons are no longer available.
  4. A constant-length set made with Pinhawk irons from Value Golf, which have yet another loft makeup. But it is very close to the iMatch setup; it is one degree stronger than iMatch in every club.
Parameters of the study:
  • Used the Dupilka trajectory software. (TrajectoWare Drive does not yet do irons.)
  • For the "standard" lofts, used the 4-degree loft spacing common in the mid-1990s, to keep things coherent.
  • Assumed 80mph clubhead speed for a 5-iron.
  • The orange row in the table shows that the 7-iron is the "pivot club". That is, all constant-length sets have a 7-iron identical to that of the conventional set. [1]
  • Following from the previous point: all the single-length irons have the same head weight [1], shaft weight, length, and therefore they are all the same as the 7-iron.
  • Corollary: they all have the same swingweight and moment of inertia as the 7-iron. [1]
  • Therefore, they all have the same clubhead speed as the 7-iron, 78mph.
Club Conventional Set Loft Carry Distance
Length Weight Speed Conventional
& Const.Len.
iMatch Pin-
iMatch Pin-
3-iron 39" 242 82 20 192 185

4-iron 38.5 249 81 24 21 20 180 176 184 185
5-iron 38 256 80 28 26 25 166 164 171 174
6-iron 37.5 263 79 32 31 30 152 151 154 157
7-iron 37 270 78 36 36 35 137 137 137 141
8-iron 36.6 277 77 40 40 39 123 124 124 127
9-iron 36 284 76 44 44 43 111 112 112 114
P-Wedge 35.5 291 75 48 48 47 97 100 100 103

Let's look at the distances provided by each set.
  • Comparing the conventional set (pink) with the constant-length set having the same lofts (red), we see that the conventional set has a little more range. The actual ranges in yards are 95 (192-97) vs 85 (185-100), a 12% difference. Other than that, they track fairly closely. What we can conclude is that the clubhead speed due to club length contributes only about 12% to the distance gap between clubs; the other 88% is due to loft.
  • As you would expect, iMatch and Pinhawk have almost the same distance trajectory. The Pinhawk is about 2 yards longer, due to the slightly stronger loft. (The reason the table and graph show variation -- 1 yard to 4 yards -- is that we have rounded off the numbers at a couple of places in the calculations. It is an artifact of computation rather than a difference between the clubs.)
  • This 88%-12% split (loft vs length) suggests that we can make up for it in a constant-length set by increasing the difference in loft from one club to the next. It would not have to be a large difference to make up for the loss in length advantage.
  • And that is what both iMatch and Pinhawk have done! Instead of a 4-degree spacing, they have a 5-degree spacing for the longer clubs, going back to 4 in the shorter clubs.
Let's get a better feel for this by working just with the gaps.

Club Carry Distance Gap
iMatch Pin-
3-iron to 4-iron 12 9

4-iron to 5-iron 14 12 13 11
5-iron to 6-iron 14 13 17 17
6-iron to 7-iron 15 14 17 16
7-iron to 8-iron 14 13 13 14
8-iron to 9-iron 12 12 12 13
9-iron to P-Wedge 14 12 12 11

Bear in mind that we have about a one or two yard rounding error, mentioned above. That gets exaggerated when you do subtration (which is how you compute the gaps), so don't pay much attention "spikes" lasting only one gap, of 2 yards or less. If it is a consistent trend rather than a spike, it is probably real.

Some of the apparent trends that the table and graph show:
  • The lowest lofts of 20 or 21 degrees do not accomplish the full capability that we expect from the rest of the clubs. The gap is considerably smaller where the longer club is 20 or 21.[2] This has been observed before. From this graph, it is clear that this has more to do with loft than the length of the club, because it is there for both the conventional and constant-length sets.
  • The conventional (pink) and constant length (red) curves track one another pretty well. It should come as no surprise that the gaps for the conventional set are a yard or two longer than the gaps for the constant-length set -- the one with the same lofts. That is because the difference in length, hence a difference in clubhead speed, will make the gaps larger than if they were due to loft alone.
  • The gap curves for the iMatch (yellow) and Pinhawk (blue) are as close to identical as you might expect. Each has a high area around 15-16 yards of gap with a dropoff on either side. The dropoff to the left we have already discussed; it is due to low lofts around 20 not delivering as much extra distance as the middle lofts.[2] The dropoff to the right is a result of the loft difference going from 5 to 4 at the 7-iron.
  • There are two possible approaches to that change of loft difference from 5 to 4 in the shorter irons, each with its rationale below. The iMatch and Pinhawk take the first of the two.
    1. The change from 5 to 4 is a good thing. That is true in spite of the gap being fewer yards in the shorter irons. It lets the distance gap be more like a constant percentage of the total distance, instead of a constant number of yards. That is, a 17-yard gap at 145 yards of distance is a 12% gap. A 13-yard gap at 119 yards of distance is 11%. So the gaps are similar as a percentage of distance. As we get closer to the target, we want better accuracy, hence smaller gaps between choice of club.
    2. Not a good thing; we should leave the loft difference at 5 across the set. It is harder to remember the distances when the gaps are percentages rather than constant yards. Also, it eliminates the need for a gap wedge because the PW would have a 50 loft.
    I understand why iMatch and Pinhawk adopted (a) above, but I might have set up my own irons as (b). Or perhaps somewhere in between; I use a 54 sand wedge, so have a lot less need for a gap wedge anyway.


The constant-length irons are generally recommended for people who have trouble with the longer irons. Such clubs will probably be a help for them, down to the 5-iron and likely even the 4-iron, at the cost of a small compression in range. The range compression gets more severe with lower loft. So constant length is not a good solution for clubs as long as a 3-iron, which should still be candidates for replacement by hybrids or lofted fairway woods.

And, while we are looking at the edges of the set, let's consider the shorter irons. (That is, clubs with more loft than the "pivot club".) Most golfers do not have a problem with those clubs. In fact, many golfers (including yours truly) are more accurate hitting the shorter clubs. For such golfers, both range compression and accuracy could be made more favorable if the higher-lofted clubs were the lengths of a conventional set.


I feel that a 4- or 5- through 7-iron with the length and mass of a 7-iron could be a big help for some golfers. But longer clubs than that should be replaced by hybrids or metalwoods. I also feel that shorter clubs are more advantageous in a conventional design.


  1. Small exception: head weight. The Pinhawk head weighs 272 grams instead of 270 grams. The difference this makes is a small fraction of a yard and one swingweight point, so we will ignore it. Another reason for ignoring it is that clubhead manufacturing tolerances are typically 3 grams, more than the difference between the sets' nominal head weights.
  2. The loss of gap at low iron lofts is not a new phenomenon. It has been there a long time. You need a lot of clubhead speed to get the same advantage going from a conventional 4-iron to a 3-iron that you got elsewhere in your irons. That makes it even more of a crime what the OEMs did to the loft lineups in the 1990s during their "loft wars". They actually reduced the loft differences for the longer irons -- which in fact was what gave rise to the gap wedge in the first place. There wasn't much of a gap before. Why did they engage in loft wars, strengthening the lofts on the short and middle irons? They wanted to tell prospective buyers, "You can hit our 7-iron longer than your buddy can hit his 7-iron." But they couldn't do it throughout the set, because (a) the average golfer this would appeal to can barely hit a 3-iron at 20, and (b) you need a certain amount of loft on a sand wedge to get out of the sand. So they compressed the loft differences in the longer irons -- exactly the opposite of the sensible approach of iMatch and Pinhawk -- and added a gap wedge.

Last modified -- 11/24/2011