Mizuno produce irons that you have to try, they’re inspirational and have a history of being used by greats of the game such as Woods and Faldo.
But when it comes to the driver, some of their staff players reluctantly use it and often hide their preferred driver under a Mizuno headcover. Can this year's offering change our perceptions through serious performance?
Introducing the final chapter of Mizuno's ST’s four year driver journey. From ST190 to ST200 to ST220, we've now reached ST230. They chased accuracy and speed and now they claim to have maxed out ball speed too and put it all in one package.
The Tech
Mizuno say that the 'missing piece' to this ball speed comes in the form of a CorTech Chamber which appears on all of the ST-230 Series drivers of 2023.
Research by Mizuno has shown that pushing weight closer to the face increases ball speed and reduces spin, which is a winning formula for hitting the ball longer.
Staff players Keith Mitchell and Luke Donald are said to have seen gains in ball speed of 2-5mph with a reduction in backspin of 200rpm.
Today I am reviewing the ST-Z 230 head which is Mizuno's lowest spinning driver and is used by both Donald and Mitchell.
It's said to be straight flying, stable and low spinning thanks to a combination of deeper and shorter CG distance which provides workability whilst still retaining high MOI.
The chase for ball speed is fulfilled with the CorTech Chamber, which is a stainless-steel weight with an elastomeric TPU. This provides stability, speed and low spin from the face, and this energy store is said to be a real step forward for the brand.
The face is a multi-thickness Forged SAT 2041 Titanium Beta and the sole is a single piece of carbon, designed to make the head lighter.
There is no moveable weight rail on the head which you may expect on a low-spin driver but the Quick Switch hosel offers 4 degrees of variation in lofts and is very easy to use.
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Mizuno ST-Z 230 Driver Review
Looks
Mizuno have been making good looking clubs for years and once again they haven't disappointed. As you'd expect from a 4th generation design the driver head looks very similar to the previous ST-Z 220. It is rounded with a deep face which means it appears smaller than the 460cc measurement.
Once again it is black with a patterned crown but this time the CorTech Chamber on the sole is highlighted in Mizuno blue. It looks awesome at address and is little different to the 2022 model, which is what Mizuno's players wanted.
Special shoutout for the headcover which is in the classic Mizuno blue and white and is superb quality, whilst being nice and large so you aren't struggling to get it on and off for every tee shot.
Feel
The driver sounds great as it isn't high pitched in strike, while the head also sits lovely behind the ball. What did trouble me was that when I saw high spin numbers I couldn't feel why, as the feedback from the club face didn't replicate the shot that I was hitting which confused me a little.
Performance
My ball speed averaged at 131mph with a carry number of 221 yards and a total of 236, which was down on my usual driver numbers.
There was one shot that caught my attention though. The ST-Z 230 showed a glimmer of hope with a standout shot of 219 carry, 242 total and over 134 mph ball speed. This is as good as it gets for me at the moment with a driver, but I just didn't see it consistently.
My spin average was 300 rpm higher with the ST-Z, compared to the ST-X at 2604 rpm which was surprising, and it flew higher too. I put this down to the straighter shot shapes as opposed to the left bias of the ST-X 230.
These numbers are not something that I expected from a low spin head, and like with the ST-X 230 I was a little confused with the results I was getting from the Trackman.
Mizuno ST-Z 230 Driver Verdict
I was surprised by the higher spin rates in the ST-Z 230 compared to the ST-X 230, although that made it better for me. The flight was straighter and the spin wasn't as low as I expected, meaning that I carried the ball 4 yards further in the air than with the standard head.
In my opinion, it's nothing like testing a Callaway Paradym Triple Diamond or Titleist TSR4.
The ST-Z head being better suited to my game is great as I normally love a small, round and deep-faced head at address but then the ball spins too little and the flight never reaches its peak height.
That didn't happen with this driver, which contradicted what I was expecting and what I was told in the brief. Testing proved that in this company's case I am suited to a driver which I didn't expect, highlighting the need to get a custom fit.
Even though it looked great I'd class the performance as average, and both the distance and ball speed numbers were down by a few yards/mph - with that one unicorn shot never to be found again.
Would I Use It?
It would have taken this driver to be among the longest and most accurate I have tested to change my perception on these drivers. My expectations were a little low and the performance just didn't wow me enough.
That one great shot did give me hope but I do not have the time or the enthusiasm to keep searching for that unicorn, when it happens more often with other manufacturers' clubs in my hand.
Who Is It Aimed At?
Players wanting a straighter ball flight and a good looking smaller head without having the spin be too low.
However, you will have to have that conversation with your playing partners of 'why are you playing that driver?', when it's funny that you would never have those same fears with the irons...
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