COST: $999.99

TESTED BY: Jimmy Emanuel, Golf Australia Deputy and Digital Editor.

FIRST IMPRESSIONS: Anyone who still refers to Mizuno as an “iron company” needs to stop, because the fact is the company is doing great work across its entire range and these drivers are proof of that.

Both look great, with a fairly traditional modern shape at address, with the composite crown look providing some nice contrast, while the sole of the ST-Z and ST-X are quite busy and the “hero” technology – CORTECH Chamber – certainly stands out.

The ST-Z is the more neutral driver of the pair and looks exactly that. Very square behind the ball, this driver looks like it wants to go straight down the fairway with some nice, rounded shaping that helps hide its size.

The ST-X is slightly draw biased, yet at address it is far from sitting significantly closed and it is only on very close inspection side-by-side with the Z that this will really stand out to the casual observer.

Off the face, feel was an immediately noticeable improvement on previous models. The CORTECH Chamber is about distance and feel, with these two drivers quite muted and solid as you would expect from Mizuno but certainly not a dead sound at impact like some carbon heads.

The ST-Z felt a little livelier off the face for mine, but the ST-X wasn’t far behind, with both drivers producing the ball flight they are built for.

HOW THEY PERFORMED: When releasing these drivers, Mizuno spoke of the importance of testing both models, with some of their Tour staff preferring the draw biased ST-X for its workability in lower lofts, while the higher lofts produce the performance more expected of a traditional draw-biased driver.

The ability to work the ball with the ST-X was certainly present, while the stock shot was a very tight right-to-left ball flight, whereas the ST-Z was just a straight shooter with a powerful and more penetrating flight.

Shaping shots was certainly easier with the ST-X, perhaps in part due to its slightly higher spin rate, and the predictability of a little draw with a standard swing was very reassuring during testing. However, the ST-Z really came into its own as a golfer who prefers to see a straight or fading flight with the driver.

Improving on the previous ST-Z in distance and feel, the ST-Z 230 comes out hot and hard, with the lower spin flight perfect for higher ball speed players who don’t hit up on the ball too much. That said, my slightly worse swings were noticeably more affected in carry than with the ST-X, while the feedback in sound and feel of an off-centre hit was more noticeable with the ST-Z.

Compared to other current model drivers, the distance of both models was right up there and anecdotally so was forgiveness, feel being where the Mizunos stood out from the pack.

The company has put a lot of research and money into its woods in recent years, and without question the ST-X and ST-Z 230 are the best drivers Mizuno have produced to date.

As suggested, there were some sightly surprising benefits from the ST-X given it is a draw model, but for me based off personal preferences in flight and performance the ST-Z was the standout of the pair, however both these Mizuno drivers are well worth your consideration.

MIZUNO SAYS: It took four years of rapid-fire development and worldwide Tour usage to raise Mizuno metal woods from the shadows of our iconic irons. Now after multiple iterative developments for stability, sound and spin we’ve added exceptional ball speeds to our performance equation. Introducing the ‘CORTECH Chamber’. 

Mizuno’s CORTECH Chamber encases a stainless-steel weight with elastomeric TPU – taking stress from the clubface and creating an additional source of energy. At the same time locating weight closer to the clubface to reduce spin rates, while contributing to a more solid, powerful sensation at impact.

A straight bias driver with great stability from off centre hits, ST-Z 230 is similar in look and character to the previous ST-Z. A more rounded, deeper profile with weight located closer to the hosel – means the ST-X 230 is slightly higher spinning and draw biased for the majority, but more workable for many elite players.

Visit the website www.mizunogolf.com to find out more.