THE MIZUNO ST-Z 230 DRIVER: Can the newly developed ‘CORTECH CHAMBER’ deliver on ball speed?

After four years development, Mizuno’s Speed Technology (ST) Metalwood Project has culminated in the ST-230 series and a new energy source known as the CORTECH Chamber.
After multiple iterative developments for stability, sound and spin, Mizuno say they have finally identified the missing piece to its ball speed equation, with the CORTECH Chamber, in its ST-230 Series due for 2023 release.
The 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, it locates weight closer to the clubface to reduce spin rates, while contributing to a more solid, powerful sensation at impact.
David Llewellyn, Director of R&D for Mizuno, said: “Our player testing over the years shows that placing extra weight close to the face results in faster ball speeds and low spin rates.
“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.”
Since 2020 all of Mizuno’s contracted professionals have played and aided in the development of the driver. Maintaining a consistent look at address, while incrementally elevating performance has built trust in Mizuno drivers amongst elite players – from college to the PGA Tour.
The Mizuno ST-Z 230 Driver
A straight bias driver with great stability from off centre hits that’s 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 an incredible, 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.
Chris Voshall, Mizuno’s Director of Product, said: “Tour tests for the ST-Z 230 have all been very consistent,.
“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.”
Availability: Right Hand – 9.5 and 10.5 degrees. Left hand – 9.5 degrees only
Price: $499.95