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Korea’s AutoFlex Shaft: Challenging the conventional wisdom of golf



We are creatures of habit, or so I’ve been told. And God knows old habits are hard to break. Just ask my right leg that simply refuses to stop reverse-pivoting, despite my best intentions.

Equally hard to break are pre-conceived notions and superstitions. There are hundreds of them to be sure, but I want to focus on one particular idea in golf that seems to be largely unchallenged for its conventional wisdom: The more flexible the shaft, the less accurate it is.

You may have heard a similar version of the same idea. Stiffer shafts offer straighter shots, faster swingers need stronger shafts, and whippier shafts result in more slice. But a recent find has caused me to challenge this well-established notion—that an ultralight, super flexible shaft (44 grams) is claiming to be not only straighter but longer as well.

My first reaction: “NO WAY”. The shaft would practically be a fishing rod. There’s no way that it would stand up to my normal swing speed of 98~100 mph.

But the kicker was that the makers of this ‘breakthrough’ shaft doubled down on me by claiming that their fishing rod-esque shaft can hold under swing speeds of up to 150mph! That’s up in the territory of world long drive champions-and they are practically inhuman! Now I was scoffing out loud—time to put the money where their mouth was.

(Jung-hwan MOON, member of Korean National long drive team, testing out the new AutoFlex FS505 shaft)

The new shaft is named AUTO FLEX. Sounds a little cheesy, until you realize that Dumina Inc., the South Korean shaft manufacturer, also makes AUTO POWER shafts that have caused a local sensation on the KLPGA and elite amateur circles over the past few years.

Autopower shafts have proven itself to be effective, largely due to a wide range of 50+ shafts offering a much smaller gapping of about 5-10 CPMs between shafts. It allowed golfers to dial into their particular swing speed more effectively. Its use of their proprietary weaving pattern and as-yet-undisclosed material KHT (Korea Hidden Technology!?) also did what it said it would. Smooth feel, mid-high launch, and great accuracy/forgiveness.


Enter AUTO FLEX, the new generation of shafts that Dumina claims will make the game of golf easier and more enjoyable for all golfers. By allowing golfers to swing more easily and smoothly with a much lighter shaft, golfers will not only feel fewer aches and pains but that their scores will improve as well.

Oh, and did I mention that there are only 3 shafts that are supposed to fit all levels of swing speeds from 65 to 150mph?

“NO WAY”, you say? I told you so.

Autoflex SF305 shaft / 38 grams / approx. 170cpm / Ladies / SS 60~80mph
Autoflex SF405 shaft / 44 grams / approx. 180cpm / Men / SS 80~95mph
Autoflex SF505 shaft / 51 grams / approx. 210cpm / Pro / SS 95~120+mph

According to the specs provided, I was fit for the SF405 shaft. The SF stands for ‘Spec Free’ meaning that these shafts do not follow the conventional labeling system of R, S, X, and weight. The first few waggles and I was at a loss for words.

Dumina claimed that after three rounds with the Autoflex, I would be well adjusted and that results would be prominent. I began by hitting a few shots with the 43-gram shaft and immediately noticed that the shaft had something much more than meets the eye.

Once I got over the initial doubt that a whippy shaft would not be able to square up to the ball at impact and started to swing normally, the shots flew straight with a bump up in launch angle. The higher launch (from 9º up to 13º) gave me more carry distance over my previous gamer, but I thought it might be increasing my backspin. But a quick check with a launch monitor showed an average of 2,000-2,100 RPM, which was about the same as before.

But the most noticeable numbers were from the total distance, which was about 5~7 yards farther than my usual average. This was surprising because I felt I was swinging a little slower and smoother than before (it may be from the fear that the whippy shaft may cause a duck hook), but the average ball speed increased from 62~63mph to about 65.

I venture that because the shaft is more flexible, it causes the head speed to increase, kind of like cracking a whip of sorts. This somewhat fits into my current belief that a more flexible shaft hits the ball longer (at the expense of accuracy).

Pretty darn good numbers for me, but ZERO side spin means a straight as an arrow shot and 1.50 smash factor.


The numbers on the launch monitor were impressive for my standards and usual play. But it needed to be tested out on the course.

At the time of this article, I have played some 10 rounds with the new AutoFlex shaft on my Cobra F9 driver (10.5°, 45.25 inches at D2) and I couldn’t be happier with my results. My driving accuracy has significantly improved over the conventional shaft (HZRDUS Smoke 6S).

I’ve played in both fair and very windy conditions, and the results were the same. I was finding a lot more fairway than ever before. That pesky little draw at the end that rolls the ball into the left rough has all but disappeared.

To be frank, I didn’t see much change in the overall distance as well-struck shots from both my old gamer and new shaft tended to go about the same distance. However, it was the frequency of how often I was able to hit the sweet spot with the new shaft that made me feel much more confident in swinging the driver on the tightest of fairways.

I am still searching for the right words to explain it, but the driver feels whippy on the backswing and yet it feels like the entire length of the shaft firms up on the downswing and at impact. At times, I was certain that the shot completely missed the center of the face and a quick check confirmed that I struck the ball on the heel or toe, well outside the center. But the resulting ball flight is either a slight push or pull with a small distance loss of about 10 yards. Yet, no bananas or duck hooks that I’ve come to associate with such mishits and feedback to the hands. What sorcery is this?

But the most beneficial factor for me was that I was swinging the club much easier and with less energy exertion than I would have done with a heavier, stiffer shaft. I had a lower back disc surgery five years ago that prevents me from making a full turn and a limited finish. Playing with longer-hitting friends invariably leads me to try to swing harder at a faster tempo, usually leading to ballooning scores.

With AutoFlex, once I dialed into the new reality with an adjusted belief about whippier shafts, I was able to maintain both accuracy and distance for the whole round and not feel as tired. And I was better able to maintain my balance with a smoother swing and not have to worry about losing distance. Perhaps this is what let me hit the face center more often. Just like the namesake, it was as if the shaft was automatically trying to help fix my swing flaws to provide maximum forgiveness.

Whatever it is, I was sold.

I now have the same spec AutoFlex shaft in my 3-wood as well. If I had trouble getting my fairway woods up in the air previously, no one would suspect that of me now.

I would love to replace all of my shafts, irons and all if I could afford it, but unfortunately, the shafts are quite expensive. The company tells me that the “hidden technology” material and the manufacturing process is quite costly (nearly seven times over regular shaft manufacturing cost), and they are available in limited quantities at 950,000 KRW (about $775) each.

For me, the proof was in my new-found fearlessness with the driver and wood. I get a kick out of waggling my driver on the first tee to the shock of my playing partners and then bust a drive down the middle. Some still can’t come to grips with the shaft despite trying for themselves. And the makers of the shaft are keeping their lips sealed on what makes the shaft behave differently than the commonly held perceptions. In fact, Dumina has not applied for a patent at all, stating that once their secret is out, it will change the way we play golf and limit their business from copycats. So whatever KHT is about, it will remain undisclosed for the time being.

What do you think? Do you have any ideas on how the AutoFlex shaft works or what are its component materials? I would be interested in hearing from other gear heads out there!



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James is a golf gear-nut living and writing about all things golf in Korea. A fan of Tiger, Fred, and Seve, he is forever seeking the holy grail of golf clubs that will lower his score. He graduated from the University of British Columbia in Vancouver, BC, Canada and has been in Korea to witness the explosive growth of golf since 1996. Despite playing golf for over 30 years and being a perpetual 10-handicapper, James steadfastly claims to be the embodiment of the Average Joe Korean golfer. He can be reached at, and often introduces cool new Asia-based golf gear on YouTube and Instagram.



  1. Greg

    Sep 24, 2020 at 9:52 pm

    I saw this shaft use today my Matt at TXG and he gain ball speed , total Distance up club speed this Shaft is the Real Deal. Just hope the price could come down! At 63 of age with a105 club head speed love to try this Shaft out. Hope this Company can keep it a secret or get a USA Patient. Very nice Company . If you ever want a old Timer to try it I will try it.

  2. Jason

    Sep 9, 2020 at 2:49 pm

    It’s a very interesting concept. As a fitter I am always looking for new innovations to introduce my clients to. This one has a long way to go, but the concept is certainly interesting.

  3. ...

    Aug 20, 2020 at 12:21 pm

    7 iron spinning 3600rpm in the first video. useless on the course.

  4. Rama

    Aug 20, 2020 at 7:22 am

    Hi James,

    How do we buy one of these? My driver swing speed is 95. So not sure SF405 or SF505. I live in KL

  5. George Steer

    Aug 17, 2020 at 12:45 pm

    Is $775 worth it if my back feels less strain and I can play longer into my senior years? ABSOLUTELY!

  6. Fishing Rod is the Future

    Aug 17, 2020 at 12:23 pm

    I always believed when everything else is equal, lighter the shaft is better. However, I never expected to see such a wimpy looking shaft to be stable during the swing. But, I think about it again – it makes a sense. Fishing rods are wimpy but stable. And, good fishing rods cost a fortune. They must be modeled after a good fishing rod.

    • James

      Aug 18, 2020 at 2:45 am

      Great observation. That is precisely what I was told 🙂

  7. Jack Nash

    Aug 17, 2020 at 9:48 am

    Question : Is it worth $700 smackers for me to gain 8 or so yards when my avg. drive is 220?

  8. Lee Ditiangkin

    Aug 15, 2020 at 1:42 pm

    Does anyone know where you can pick these up in the US

    • James

      Aug 16, 2020 at 8:54 pm

      Hi Lee.At the moment, the AutoFlex shafts are available in Korea only but I believe the company is looking for capable distributors in North America. I will update when and if they are sold there. If you are looking to purchase asap, email me for info to the company. 🙂

      • Jonathan Keith

        Aug 19, 2020 at 3:27 pm

        I would love to get one soon!

        • Lee Ditiangkin

          Sep 22, 2020 at 8:11 pm

          Just got the shaft. Couldn’t miss a fairway, something different about this one.

          Sometimes it appeared the shaft would break at the top of the backswing, but at impact felt pure. Took a while to get used to the flight of the ball because it takes off at a higher window.

          You can swing fast or slow, the shaft responds pretty much down the center.

          Going to play another couple weeks and want to practice with a trackman to see the numbers.

          Coming from a tpt 15, so this is a drastic change.

      • Michael

        Sep 24, 2020 at 7:45 pm

        Sent you a message James. Thanks.

      • Jerry

        Sep 24, 2020 at 10:33 pm

        I would like to get one of these shafts, im also dealer for different makes of clubs and drivers,
        How do I get in contact in getting these shafts?

    • geohogan

      Sep 23, 2020 at 4:41 pm

      try ebay in two or three years for $300, with free delivery.

  9. Benny

    Aug 15, 2020 at 1:20 pm

    Great article. Fellas the Rogue 125msi sold for $1200 and many bought those shafts. Not applying for a patent means it cannot be controlled by a manufacture, that theyinvested something. So thisis something abvious and easy.
    I have always thought about a shaft that has to be installed in a specific way for each player, on their plane. That the walls are built up so not to allow the head to twist ever and only flexes backwards on the plane.
    If thats the case the more “whip” the better it helps and zero chance of misdirection or miss hits.
    Maybe its illigal and why its not been marketed. But if we do not play USGA golf than who cares?

  10. Paul Runyan

    Aug 15, 2020 at 12:10 pm

    I think I will wait for Ian and Matt at TXG to do some testing!

    This will probably work well for Some seniors, etc., but I would love to see Matt try this out in his new Callaway or better yet the old Ping G410.


    • gwelfgulfer

      Aug 16, 2020 at 1:05 pm

      Do a head to head with the Nunchuk to see who rules the one flex for all category.

      • geohogan

        Aug 23, 2020 at 12:29 pm

        Last I looked Nunchuk driver shaft sold for $250, and Xi iron shaft $60

        A no-brainer at 1/3 price.

    • ko

      Aug 17, 2020 at 4:22 pm

      Freaky diky mavericky

    • Sean P Momtahen

      Sep 24, 2020 at 4:49 pm

      Go check out their youtube… the review came out today and it pretty amazing TBH

    • Johnny Penso

      Sep 24, 2020 at 7:46 pm

      Video came out today. Matty gained an avg. of 20 yards through the air. Longest driver was over 370 yds.

  11. Walter E. Welky Jr

    Aug 15, 2020 at 12:01 pm

    Sounds like it is capable of flexing from 9 o’clock to 3 o’clock with zero torque. Is there an orientation mark on the shaft that would render adjustable clubs useless?

    • James

      Aug 19, 2020 at 11:44 am

      I don’t see any such markings on the shaft. And I adjust my driver’s loft from time to time and don’t see any effect on accuracy.

  12. TonyK

    Aug 15, 2020 at 10:50 am

    This made me curious.. We all know that there are illegal driver heads, but can there be any “illegal shaft” at all?

  13. jim

    Aug 15, 2020 at 10:17 am

    Those “in the know” have known this for years…..hardest part is trying to get golfers to get over their misinformations, personal feelings and preconceived notions as to what is going to happen during golf swing. Hit a 13* driver? what? no way, it will go to high !!! Not.

  14. Glenk

    Aug 15, 2020 at 7:28 am

    Excaliber shafts here in America has been doing this for years in wedge shafts to create extra feel and spin. They are now releasing this same concept in irons and soon woods – called rapid taper shafts. Hackers paradise reviewed the iron shaft and got 8 extra yards from this shaft with better carry numbers. Exxcaliber will not be charging ridiculous prices for theirs though thankfully.

  15. JM

    Aug 15, 2020 at 3:08 am

    When I was younger, I had no money and would buy clubs from Play It Again Sports. I found a nearly new Callaway Steelhead 3 wood for $80 and picked it up. I had no idea what specs were or even why they mattered. I loved that 3 wood. Straightest club in my bag and I always striped it. One day im playing with a good player and i crush my 3 wood. He asks to check it out and proceeds to tell me that it has a women’s shaft in it. I got rid of it immediately and have never hit a 3 wood that good since.

    • Rothkofan

      Aug 15, 2020 at 8:54 pm

      Freddie Couples gamed a 3 Wood for years…that he stole from Tom Watson’s then-wife

    • nomad golfer

      Sep 1, 2020 at 6:53 am

      One thing this article has done for me and that is my rejection of ladies flex has gone and I know where there is a lovely 7 wood (L) and I’m going to buy it tomorrow. I should have known because My old TM R7 and R11 have geriatric shafts and hit like winners. Thanks

  16. DPavs

    Aug 14, 2020 at 12:59 pm

    The price makes this a no go for the average golfer… so it’s a fail for me.

  17. dat

    Aug 14, 2020 at 11:13 am

    LOL $775 for a shaft?

  18. George Steer

    Aug 14, 2020 at 10:52 am

    Great article James!
    Does the company have any plans to market in the United States?

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Wunder: Titleist TSi driver first impressions



Three things I want to address before I kick this off.

  1. “Better, best” will not be addressed. It’s never about that these days only what works for me or you.
  2. I’m not adding TrackMan data to this for one simple reason: It doesn’t matter to me for a first impression. I can get lost in the data and ultimately it confuses my ability to just enjoy the sound feel and look of the driver. Obviously, the fitting was on TrackMan, but in the past, successful drivers for me started with the emotional part. Simply, do I like the thing? Can I look at it? Can I trust it? Can I hit shots with it? That’s it.
  3. When I say “spin this” and “spin that,” it’s always addressing a positive aspect.

On Tuesday of this week, I had the good fortune of visiting the Titleist Performance Institute (TPI in Oceanside, California) to do my TSi metal woods fitting. Won’t get too far into that, but essentially it’s golf heaven in every sense of the word. Like TaylorMade’s Kingdom or Callaway’s ECPC, TPI it’s a gearhead paradise.

Titleist Master Fitter Joey Saewitz (@thejoeysaewitz on IG) was my fitter and after hitting a few balls to warm up, we dug into my gamer driver that I adore.

Current Gamer Spec

TaylorMade SIM (9 degrees @ 8.5). Fujikura Ventus Black 6X (no tipping) 45 inches, D4, GolfPride BCT 58R

I have been constantly messing with my driver between new shafts, lofts, lie, etc. Since I’ve been playing a bit more this month, I’ve had the chance to work on my swing and the driver has been the last thing to come around. I’m working on decreasing dynamic loft through the bag and have not adjusted my driver to match. The point is, I’m hitting the driver solid but have lost a ton of height and spin to keep it in the air.

I’m saying this now because for key metrics I was at a deficiency because of the craftsman not his tools. The SIM I was fit into was/is excellent. So, as you read on, keep in mind that I knew that numbers-wise apples to apples my setup was vulnerable to getting beat out due to my tinkering.


My average numbers these days are are 105-108 mph swing speed, 155-160 mph ball speed, 14-degree launch, and 1,800-2,000 spin. At 43-years-old, when I’m hitting it solid I get a lot out of my driver. IF I’m swinging well, at my low spin, off days can be nauseating with the driver.


TSi3: If two of my favorite drivers 975D and R7 Superquad TP had a baby, the TSi3 would be it. Its flawless appearance-wise. The heel section gives it an onset look that the faders will love and the top line toe section is a bit rounded off to give it an open look without having to crank it open. Not the first time we have heard that but nonetheless, Titleist nailed it.

The face has a cool matte finish that I can’t get into yet, but it frames a white ball excellently.

TSi2: Like the TS2, it has that high-MOI shape, although I will say the top line and transitions are a bit softer on the eye. It’s a driver that looks like it just wants to go high and far. If I wanted to hit something as hard as I could that’s the shape I would look for.

Side note—the black shafts in the TSi3 are almost too cool to even look at—the closest thing to a Darth Vader golf club I have ever seen.


This is where they really figured it out. Titleist drivers in the past to my ear sounded good but not great. There was always an essence of ting that I couldn’t fall in love with. The TSi series fixed that in totality, like all the great drivers on the market in 2020 it has that hammerhead thud that I adore. When you crunch it, you literally hear crunch. At impact, however, it has a more compressiony (is that a word?) feel than its competitors. The comparison would be a one-piece forged feel vs a hollow body players iron. Both feel excellent but there is a difference. You can feel the ball squeeze into the face which I think most will notice and respond well to.

PERFORMANCE—Not going to compare it to my gamer as it’s not fair, I gear headed my gamer to the point of lunacy. I will only comment on what the TSi series did while testing.

TSi3: The biggest standout here was usable spin. I am not a high-spin player by any stretch, so if I can find a driver that gets me 2,100-2,200 consistently when I flush it, it’s a contender. For a player at my speed to sneak it out there with the big hitters, I have to launch it at 14 at 1,700 spin, and hope I’m aimed correctly. What I found with the TSi was I was getting that performance at 2,100-2,200, and if anything only giving up 2-3 yards all while doing it 5/10 times as opposed to 2/10.

What does all that jibberish add up to? Consistency and something I can play with. Is it longer than my gamer? I have no idea, but we will find out. What I know is I hit a bunch of really good shots with TSi3, and after I got going with it, it was point and shoot. Stable? Yes. Long? Yes. Forgiving? Yes. Playable? Yes.

TSi2: To be honest I only hit a few with the Tsi2 as its not my genre of music. What I can say is it feels apples to apples with the Tsi3, launches higher with a bit more spin, and goes really straight. No shocker there. The high MOI category has a bunch of contenders, and in my opinion, it’s a head weight game. Heavy is always better for stability.

The setup I landed on

I was fit into the (D4 SureFit setting 9 degrees @ 9.75, flat) however after testing a bit at home on course and range, I landed on the D1 setting, which I like. For whatever reason, I can play Tsi3 at 8.25 and still maintain height spin and it flew about five yards further.

Final setup

Driver: Titleist TSi3 (9 degrees @8.25, D1 SureFit, 44.5 inches, D4 swing weight)

Shaft: Fujikura Ventus Black 6 X (tipped 1)

Overall, the TSi Series drivers will be VERY popular but not for the reasons you would think. It’s playable, you can hit shots with it, that’s the mark of a GREAT golf club. It’s not all ball speeds and carry anymore in my opinion. This is a driver I can go out and play well with, that’s huge for a hack like me. In my experience, I can’t say that about a lot of drivers I’ve tried to make work in the last four to five years. That’s just me. Lots of great drivers every year but I’m a hard case and finding one that’s just right is a challenge.

Ultimately, for me, the best driver on the market is SIM hands down because it performs in the hitting bay and even better on the course—my hunch is Titleist has something that will do the same.

It’s a beautiful driver that I thoroughly enjoyed getting to know.


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GolfWRX Classifieds (9/25/20): Titleist U510, XXIO Red, Tour issue M5 head



At GolfWRX, we love golf equipment plain and simple.

We are a community of like-minded individuals that all experience and express our enjoyment for the game in many ways. It’s that sense of community that drives day-to-day interactions in the forums on topics that range from best driver to what marker you use to mark your ball, it even allows us to share another thing – the equipment itself.

One of the best ways to enjoy equipment is to experiment and whether you are looking to buy-sell-or trade (as the name suggests) you can find almost anything in the GolfWRX BST Forum. From one-off custom Scotty Cameron Circle T putters, to iron sets, wedges, and barely hit drivers, you can find it all in our constantly updated marketplace.

These are some of the latest cool finds from the GolfWRX BST, and if you are curious about the rules to participate in the BST Forum you can check them out here: GolfWRX BST Rules

Member Yenmaster – TaylorMade M5 driver head

If I’ve said it once, I’ve said it 100 times—if you already have a shaft that you love, buying a driver head is the best way to upgrade and save a few bucks along the way. Is it time for you to trade up?

To see the full listing and additional pictures check out the link here: M5 Driver head

Member dansrixon – XXIO X Red Driver

This listing is littered with really cool and rare drivers and fairway woods from Cleveland, Srixon, and XXIO, including the XXIO Red driver looking for a new home.

To see the full listing and additional pictures check out the link here: XXIO Driver

Member kkennedy – Titleist U510 1-iron

The new U500 series utilities are the fastest and most forgiving Titleist have ever made, so if you are looking for a club to keep the ball out of the wind—here you go!

To see the full listing and additional pictures check out the link here: Titleist 1 Iron

Remember that you can always browse the GolfWRX Classifieds any time here in our forums: GolfWRX Classifieds

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Whats in the Bag

WITB GolfWRX Members Edition: Rkelso1984



Recently we put out the call for our members to submit their WITBs in our forum to be featured on the GolfWRX front page. Since then, our members have been responding in numbers!

Now it’s time to take a look at the bag of Rkelso1984.

*Full details on the submission process can be found here, and you can submit your WITB in this forum thread.*

Member: Rkelso1984


Driver: Callaway Mavrik Max (10.5 degrees, set to 9.25 degrees)
Shaft: Oban Devotion-6 04 Flex 65g

3-wood: Callaway Mavrik Sub Zero (15 degrees)
Shaft: Aldila Rouge 130MSI 70s

5-wood: Callaway Mavrik Sub Zero (18 degrees)
Shaft: Aldila Rouge 130MSI 70s

Hybrid: Titleist TS2 (19 degrees, set to 20.5 degrees)
Shaft: Project X Evenflow 6.0S 90g HY

Irons: Mizuno JPX 919 HMP (5-PW)
Shafts: KBS C-Taper lite 110s

Wedges:  Mizuno JPX 919 (50 degrees), Callaway Jaws (54, 58 degrees)
Shafts: KBS C-Taper lite 110s, KBS Hi-Rev 125s

Putter: Ping Heppler Ketsch (34″)

Putter Grip: Golf Pride Tour SNSR Contour Pro 140cc

Golf Ball: Taylormade TP5x PIX

Grips: SuperStroke TX1 Mid + 1 Wrap

Get submitting your WITB in our forum as we’ll be publishing more and more of them on our front page over the coming days and weeks.

Feel free to make it your own too by including some thoughts on your setup, your age, handicap, etc. Anything you feel is relevant!

Share your WITBs here.

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