Mizuno ST-X 230 Driver Review

Over the last few years, we have been consistently impressed by both the looks and performance of Mizuno’s ST drivers. Offering a good mix of classic Mizuno aesthetics and strong all-round performance, the ST franchise has been gradually improved year-on-year. And so onto 2023 and the launch of two new drivers - the ST-Z 230 and the model that we are focussing on in this review, the ST-X 230.

The new ST-X model is described by the brand as the more workable, mild draw-biased driver. It’s unusual for the more workable head to also have draw bias. What you tend to find in the draw bias offerings from other manufacturers, is a bigger-looking head. The Cobra Aerojet Max is a good example of this. 

Of the two models, the X is fractionally more compact to look down on but it’s still quite generous and user-friendly behind the ball. Compared to the Z model, however, it is more rounded and less stretched back.  

I love the use of blue chamber on the sole, which looks high tech and very premium. The number one reason why it’s here, though, is not for the looks, even if it does boost its shelf appeal. This part of the club is where the key new technology resides.

Mizuno says it has identified the missing piece to its ball speed equation with the CORTECH Chamber (highlighted by the blue strip on the sole). According to the brand, this encases a stainless-steel weight with elastomeric TPU, taking stress from the clubface and creating an additional source of energy. At the same time, it locates weight closer to the clubface to reduce spin rates, while contributing to a more solid, powerful sensation at impact.

In terms of the crown view, it’s similar to what we saw with last year’s Mizuno ST-X 220 driver, and the gloss finish is similar to what you see this year with the TaylorMade Stealth 2 driver. The carbon effect adds a modern hint to an otherwise very classic shape that I really like.

I tested both new models as well as last year’s versions, using a GC Quad launch monitor at Foresight Sports European HQ. The shaft used for testing was a Hzurdus 6.0 60g with the drivers set to 9.5 ̊, and I hit Titleist Pro V1x golf balls. Here is the data from that testing session:

As Mizuno suggest, I was expecting the ST-X to be the slightly higher spinning of the two new models, but as you can see it spun just under 300rpm less than the ST-Z. It was the same story with the previous generation drivers too (and interestingly, looking over my data from last year’s testing, it was the same then too).

Having hit both new drivers, I can confidently say that considering the looks and the spin performance it’s quite difficult to pigeonhole a player into either the X or Z. I’m certain Mizuno would recommend getting custom fitted, and this would definitely be my advice.

What I really like about the ST-X is how it sits nicely square down behind the ball, which I’d liken to the Ping G430 SFT driver. Despite the neutral face angle, every shot I hit had a draw bias to it, whereas the flight was noticeably straighter with the Z. In a head that doesn’t look hugely different, the contrast in performance was clear to see. The internal design of the head does a great job of affecting the ball flight. 

In truth, I wasn’t quite as consistent with this model as I was with the ST-Z. Given my tendency to hit the odd hook, the straighter flight of the Z version would certainly be my preference.

However, if you’re looking to guard against the right side of the golf course but you want a driver that sits nice and square at address, then the ST-X 230 is definitely well worthy of consideration.