Mizuno say their ST-230 range features the “missing piece” in ball speed

Mizuno ST-230 range

Mizuno say their new CORTECH Chamber is the key to faster ball speeds and increased distance.

Mizuno will likely always be known first and foremost for their irons, which many golfers believe are unmatched in terms of desirability and feel.

But the Japanese brand have also been been producing good quality drivers, fairway woods and hybrids for many years, without ever matching the likes of TaylorMade, Callaway and Ping in terms of sales numbers or tour usage.

Marketing budgets play a large part in that, of course, but it’s also true that few golfers would think of Mizuno if they were seeking the out-and-out longest-hitting club in any of the aforementioned categories.

But, with their latest offering, the ST-230 range, Mizuno say they have found the “missing piece” in their ball speed equation.

They’re calling that “missing piece” a CORTECH Chamber. It 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.

“Our player testing over the years shows that placing extra weight close to the face results in faster ball speeds and low spin rates,” says David Llewellyn, Director of R&D for Mizuno. “We’ve been steadily working towards the CORTECH Chamber, which is incredibly effective at that job.  Encasing the steel weight within the TPU Chamber means that we’re moving weight close to the face at the same time as creating an additional source of energy.  Steel is twice the density of Titanium but won’t weld directly, which is where the TPU has a second role.”

The CORTECH Chamber features in all three Mizuno ST-230 drivers, as well as the ST-Z 230 fairway wood and ST-Z 230 hybrid.

Mizuno ST-230 Drivers

There are three models in the Mizuno ST-230 driver family: the ST-Z 230, the ST-X 230, and the ST-X PLTNM 230. Let’s look at each model and see which type of golfer it will suit.

Mizuno ST-Z 230 Driver

RRP £499/$549
Available 19 January 2023
Released 19 January 2023
Lofts 9.5º, 10.5º
Adjustable Hosel Yes
Availability Right Hand and Left Hand (LH 9.5º only)

The Mizuno ST-Z 230 driver is designed to be straight, stable and low-spinning.

It’s designed for straight flight, with great stability to keep off-center hits flying in the right direction. The ST-Z 230 is similar in look and character to the previous ST-Z.

The Forged SAT 2041 Beta Ti face is boosted by the CORTECH Chamber to be faster from the face, spin less and deliver a solid sensation at impact, while the carbon sole plate is now a single piece to allow weight to be pushed to the extremes for overall stability. It offers a modern players’ profile and Quick Switch hosel with 4 degrees of adjustability.

“Tour tests for the ST-Z 230 have all been very consistent,” says Chris Voshall, Mizuno’s Director of Product. “Firstly, an appreciation that the look is familiar at address, then satisfaction at how much better it feels off the face. Ball speeds are up on average 1-3mph with spin rates dropping around 200 rpm.”

Mizuno ST-X 230 Driver

RRP £499/$549
Released 19 January 2023
Lofts 9.5º, 10.5º, 12.5º
Adjustable Hosel Yes
Availability Right Hand and Left Hand (LH 10.5º only)

The Mizuno ST-X 230 driver is more workable than the ST-Z 230 and has a mild draw-bias.

That’s not to say it’s simply a slice-busting model aimed at higher handicappers, however. In fact, natural drawers of the ball may actually find more ball speed from the ST-X than the ST-Z. And Mizuno’s testing has shown the ST-X 230 is also more workable for many elite players, especially in lower lofts.

Overall, a more rounded, deeper profile, with weight located closer to the hosel, means the majority of golfers will find it slightly higher spinning and draw-biased.

“The new ST-X 230 is a complex character,” says Chris Voshall. “Although in the higher loft option it’s a higher flying draw-biased option, the 9.5 for many of our tour players was more workable and faster from the face. You really need to hit both models before making any judgments on which is likely to work best for you.”

While some brands are very directional about the type of golfer each of their driver models is targeting, things are a bit more nuanced with Mizuno. As Voshall says, the key thing really is to test both models and see which works best for you.

Mizuno ST-X PLTNM 230 Driver

RRP £499/$549
Released 19 January 2023
Lofts 10.5º
Adjustable Hosel Yes
Availability Right Hand 

The Mizuno ST-X PLTNM 230 is a high-launching, super lightweight, draw-biased driver that’s ideal for golfers with slow-to-moderate swing speeds.

The ST-X PLTNM is 30g lighter overall than any possible custom option of the ST-X 230, with a high spec Helium Platinum Shaft and lightweight grip.

Weight is located closer to the shaft axis to create draw bias and the Quick Switch hosel offers 4 degrees of adjustability.

Click here to see full reviews of the Mizuno ST-230 drivers.

Mizuno ST-230 Fairway Woods

The Mizuno ST-Z 230 is a mid-to-low spinning, high launching, adjustable fairway wood.

While many brands now have three fairway wood offerings aiming to target a variety of golfers, Mizuno feel the ST-Z 230 can be all things to all men. Although it was developed hand in hand with Mizuno’s tour advisors, it’s mid-sized and playable for all levels.

The carbon composite crown offers a low center of gravity and stability while the expanded front-to-back weighting delivers consistent launch characteristics.

The Quick Switch hosel offers 4 degrees of adjustability.

“The elevated ball of the CORTECH Chamber is a great addition to the ST-Z fairway woods, but the stability might be the real stand-out,” says Chris Voshall. “They feel like they are on tracks through impact.”

The ST-Z 230 fairway wood is available as a 3-wood and 5-wood for right-handed golfers, and as a 3-wood only for left-handers.

Check out our full review of the Mizuno ST-230 fairway wood.

Mizuno ST-Z 230 Hybrid

The Mizuno ST-Z 230 hybrid is a mid-to-low spin, high-launch, adjustable hybrid.

It comes in a range of lofts, but, unlike many manufacturers, comes in only one model. Brands like TaylorMade and Callaway tend to release more than one model with different target golfers in mind, but Mizuno feel the ST-Z 230 can do it all.

It has a slightly larger, more playable footprint than its predecessor the CLK, with a waffle crown and thick sole weight engineered to create a low sweet spot and deep center of gravity for high launch and efficient spin rates.

“The CORTECH Chamber is very effective on the fairway woods and hybrids as it does such a good job of lowering the sweet spot – maintaining ball speeds when you have to pinch one from a tight fairway,” says Mizuno’s Chris Voshall.

The ST-Z 230 hybrid is available for right-handed golfers as a 2H (16°), 3H (19°), 4H (22°) and 5H (25°). Left-handers can get a 3H (19°) and 4H (22°).

Mizuno’s previous hybrid, the Mizuno CLK, was a solid but not standout performer in our hybrids test last year. It will be interesting to see if the ST-Z 230 offers enough improvement to secure a place among our pick of the best hybrid golf clubs.

Check out our full review of the Mizuno ST-230 hybrid.

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– Which Mizuno iron is best for me?
– Mizuno ST-230 driver review
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