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Opinion & Analysis

The Wedge Guy: Industry insight – Birth of an idea



A GolfWRX reader wrote me the other day to ask how I got into the design and specialization in wedges, so I thought I would share this story with you all. I hope you find it interesting.

As most of you know, I’ve been in the golf equipment industry for almost 40 years. I actually started out on the marketing side but evolved into a club designer as well, as my tinkerer personality and habits began to manifest. My marketing background actually serves my club design work, because all impactful product development springs from an awareness of a genuine consumer problem or opportunity, whether it’s a golf club or an iPod.

As for that tinkerer personality, I was the kid who always took my toys apart to see how they worked and then put them back together—hopefully, so that they would work again. That mechanical curiosity was nurtured by my patient father, who entertained all my questions as we took apart our fishing reels, shotguns, etc. to clean and maintain them.

When I became involved in the golf industry, I spent an inordinate amount of time in the back end of Ray Cook and Otey Crisman putters, Joe Powell Golf, and others, as I was completely fascinated with how and why golf clubs worked. You see, I don’t remember life before golf–another gift from my father. He and our local golf pro nurtured my commitment and curiosity about the golf swing and the game while mentoring me to become a scratch golfer.

Anyway, that curiosity and imagination led me to my first original putter design in the mid-1980s and then over a hundred more putter designs in the years following.

But it was a golf trip to Scotland in 1990 that triggered my interest in wedges. My brother and I had played the New Course at St. Andrews our first day there and the tight lies and firm turf proved challenging with my then-new “brand X” sand wedge.

As we were touring Auchterlonie’s Golf Shop the next morning, I saw a grinding wheel and an idea just came to me. I asked if I could come back with a wedge to grind on it some, to which they said OK.

So, I went back to the hotel and got my conventional sand wedge – this was long before all these diverse grind options were available. I don’t think wedges even had a bounce designation on them at the time.

Anyway, I proceeded to grind away on the trailing part of the sole until I had reduced the bounce by probably half. I wasn’t really measuring as much as eyeballing. Then–and why this idea hit me, I’m not sure–I proceeded to grind the leading 1/4 or so of the sole to create a very aggressive bounce in the range of 20-25 degrees. In fact, I ground almost all the way up to the first groove, making the wedge look very odd.

By this time, the wedge was butchered pretty good, as I was not a trained grinder by any stretch of the imagination. So, I then ground more off the bottom of the hosel and in the heel to make it as visually palatable as I could. By the time it got to looking reasonable, of course, I had compromised the head weight dramatically.

So, I bought or borrowed some lead tape from the shop and proceeded to pack the back of the wedge to bring it back up to D4-5, as I remember.

And the results were very gratifying. Hardpan to bunkers, soft lie to rough—this thing was odd-looking, but amazing. My brother and I took turns with my wedge the rest of the trip – from Carnoustie to The Old Course, Turnberry, and Troon. He even nicknamed it “Quasimodo,” after the character in The Hunchback of Notre Dame. We were both extremely excited about what I had created in the back of the shop in “The Old Grey Toon,” as St. Andrews is often called.

So, when I returned to the states, I bought several conventional sand wedges out of the bargain barrels and began to experiment–this time in a bit more sophisticated manner. I found a welder who would add material onto the soles and purchased a grinder so that I could try different grinds. Each time, I would take them out for testing by myself and by some very good players I knew. But I also had mid- to high-handicap players testing, and they were even more enthused than the scratch players and pros in my test group.

[NOTE: That’s when also began to realize there was a big difference in the wants and needs from wedges between the better players and those not so advanced]

And that was how “the Koehler Sole” was invented.

After three years of legal work, in 1994 I was awarded U.S. Patent #5,301,944 for incorporating two positive bounce angles into the sole of a club. And I have incorporated that feature into every wedge I’ve ever designed, from Merit Golf to EIDOLON to SCOR to Ben Hogan, and now for Edison Golf. It’s been called the “Dual Bounce Sole™” and the “V-Sole®”, but each iteration has been an improvement on the one before, and it has earned a pretty loyal following through those brands.

I should add that along this journey, I also began to dramatically increase the mass in the top half of the wedge as well.

But that’s another story I am happy to tell if you are interested.

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Terry Koehler is a fourth generation Texan, a native of a small South Texas town and a graduate of Texas A&M University. He has had a most interesting 40-year career in the golf industry. He has created five start-up companies, ranging from advertising agencies to golf equipment companies. You might remember Reid Lockhart, EIDOLON, SCOR, or his leadership of the reintroduction of Ben Hogan to the golf equipment industry in 2014. For almost 25 years, his wedge designs have stimulated other companies to slightly raise the CG and improve wedge performance. He has just announced the formation of Edison Golf Company and the new Edison Forged wedges, which have been robotically proven to significantly raise the bar for wedge performance. Terry serves as Chairman and Director of Innovation for Edison Golf, which can be seen at Terry has been a prolific equipment designer of over 100 putters and several irons, but many know Koehler as simply “The Wedge Guy”, as he authored over 700 articles on his blog by that name from 2003-2010.



  1. Paul

    Mar 25, 2021 at 5:15 pm

    What ever became of Quasimodo?

  2. Paul G.

    Mar 24, 2021 at 12:18 pm

    Just wanted to say how much I enjoyed reading this particular article. I’m a (Canadian) Mechanical Engineer who’s dove into club building on the side as a hobby. It’s always been a fantasy dream of mine to work as a design or manufacturing engineer in the golf industry and these articles by Terry always seem to give me that glimpse into that world from a professional point of view. Apart from being a good writer I find your passion for the game and process of it always comes through, so thanks for that and keep up the great content.

    Also wanted to mention I recently cut down my stock length driver after reading a few of your articles. The first round out was really positive from an impact point – thanks for the tip there, feels like I’ll be smoking the sweet spot a lot more this summer.

    Hope to keep seeing your articles every week, Terry.

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Best fairway and hybrids of 2021 with GolfWRX’s Barath and Knudson



GolfWRX’s list of the best fairways and hybrids for 2021 is out and being talked about all over—these lists were created by data from the best fitters from the USA and Canada. Ryan Barath and Brian Knudson discuss what made the list and some surprises that missed.

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Opinion & Analysis

Fix your golf back pain, Step 1: The importance of assessment



This article is co-written with Marnus Marais. Since 2011, Marnus has worked with some of the world’s best players on both the PGA Tour and European Tour, helping them to maintain optimal health and peak physical performance. His current stable of players includes Dustin Johnson, Patrick Cantlay, and Louis Oosthuizen, amongst others. 

This article is No. 1 in a 4 part series:

Step 1: The Importance of Assessment

Step 2: Early Stage Rehab

Step 3: Functional Strength and Golf Movement Patterns

Step 4: Building global strength for prevention of future injury


If your back pain has been bugging you for a while and is starting to annoy and worry you, then your enjoyment of the game and your performance is likely beginning to be affected too. It’s frustrating, and you are ready to take action……..with your new foam roller and exercise bands in hand, you’re ready to knock the back pain on the head finally and forever. 

Please wait a moment before you start!

Back pain and especially back pain in golfers, is a complicated thing. More often than not, it’s the result of many contributing factors, and is vitally important that you identify what those factors are before you start your mission to fix your back pain. We really can’t stress this point enough! We have seen many people start a program to ‘help’ or ‘strengthen’ their backs, but only succeed in making them worse and getting even more frustrated.

As the famous saying goes: “If you’re not assessing, you’re guessing!”

To help successfully address your back pain, we must first identify what the main causes are. In our experience, it’s usually a combination of factors from these three categories:

1 – Physical issues (muscle imbalances, alignment issues, muscle weakness, lack of strength endurance, etc.)

2 – Golf swing mechanics (swing faults such over-swinging and excessive side bend)

3 – Lifestyle factors (sleep, diet, hydration, stress, posture, activity level outside of golf, etc.)

To help identify contributing physical issues, specific physical tests and screening tests are extremely valuable. There is a range of these we like to use, and in this article, we will share 5 of the main ones with you. These are tests we often use with our professional golfers on the road and remotely when we can’t see them in person. They are also go-to tests and screens we use with our online clients who can do them in the comfort of their own homes.

These tests will help give you an indication if an underlying alignment or muscle imbalance issue could be a contributing factor to your stubborn back pain. Please read the instructions carefully! Even though they seem like ‘simple’ tests, they are subtle, and the more careful you are with the execution, the better the results will be.

With all these tests, it can be helpful to take a picture or video with your phone. It is also useful to have them documented for comparison with future test results.

Test 1 – Leg Length Test

  • Start by lying on your back relaxed.
  • Rest your arms at your sides on the floor. Take a normal breath in through your nose. Exhale fully through your mouth to bring the ribcage downward and to feel your lower back make contact on the floor.
  • Ask a friend or family member to have a look at the bones on the insides of your ankles (medial malleolus).
  • Are they the same level, or is one higher/lower compared to the other one?

Test 2 – Seated Ankle Mobility Test

  • In bare feet, sit with both heels on the floor and your back resting comfortably against the back of the chair.
  • Hips and knees should be bent approximately 90 degrees each.
  • Keeping your heels on the ground, feet flat, and toes pointing straight ahead.
  • Slide your foot straight back until your heel starts lifting up off the floor. Stop as soon as the heel starts lifting up.
  • Note the distance. Keep that foot there.
  • Now repeat on the other side.
  • Note if there is any difference in range of motion between the two sides.

Test 3 – Seated Rotation Test

  • In bare feet, sit on the front half of a chair with both heels on the floor.
  • You should feel your “sit bones” in contact with the chair.
  • Find the center of both heels and maintain the position throughout the test.
  • Place a foam roller, small ball or equivalent object of about 4-6” in diameter between your knees.
  • Place a broomstick, golf club or the equivalent across the front of the shoulders with your arms crossed.
  • Keeping your heels centered at all times and holding the stick stable across the front of your shoulders, turn the shoulders as far as you can to the right.
  • Note how far and how easily you can turn to your right side.
  • Return to the starting position.
  • Again, keeping your heels centered at all times and holding the stick stable across the front of your shoulders, turn the shoulders as far as you can to the left.
  • Note how far and how easily you can turn to your left side.
  • Repeat the test a few times to ensure an accurate measurement.
  • Take note of any difference in range of motion between the two sides, and areas of restriction and discomfort.

Test 4 – Supine Hip Internal Rotation Range Test

  • Start by lying on your back relaxed.
  • Rest your arms at your sides on the floor. Take a normal breath in through your nose. Exhale fully through your mouth to bring the ribcage downward and to feel your lower back make contact with the floor (as discussed above).
  • Lightly squeeze either your fists, foam roller, or a small ball between your knees.
  • Rotate your feet outwards while maintaining 90 degrees at your hips and knees.
  • This will measure your hip internal rotation range of movement.
  • Go as far as comfortably possible. Don’t force it.
  • Take note of the range of motion and any difference between the two sides.

Test 5 – Seated Hip External Range Test

  • Sit with both heels on the floor and your back resting comfortably against the back of the chair.
  • Bring the outside of your ankle and place it on the top of the opposite knee.
  • Go as far as comfortably possible. Don’t force it.
  • Relax in this position.
  • This will measure your hip external rotation range of movement in the seated position.
  • Repeat on the other side.
  • Take note of any difference in range of motion between the two sides, and areas of restriction and discomfort.

If there is an imbalance or difference between the left and the right sides in any of the above tests, it could be an indication that you might have an alignment or muscle imbalance issue that needs to be addressed first before you start any strengthening program. You wouldn’t want to throw a bigger, more powerful engine in a car with poor alignment and bad suspension!

In the next article; Step 2: Early Stage Rehab, we will provide you with exercises that can help improve mobility / flexibility, muscle imbalances and posture issues.

If you would like to see how Marnus can help with your golfing back pain, then check out the resources below:

Marnus Marais –

If you would like to access training programs designed for elite and recreational players, then check out the following resources and services from Nick at Golf Fit Pro:

Golf Fit Pro App (iOS)
Online Training
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Club Junkie

Club Junkie: Reviewing TaylorMade and Miura Irons, All-Fit Universal Shaft System



TaylorMade’s new SIM2 Max and SIM2 Max OS irons are meant to make the game easy and fun, but they both offer solid sound and feel. Miura is going to make a splash in the game improvement with its PI-401 iron. Really solid performance with a great feel that you would expect from Miura. All-Fit is a new universal shaft system that allows you to use any shaft in any driver head. They have a few limitations, but overall a great way to tinker.

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