Mizuno ST-Max 230 driver

Gear: Mizuno ST-Max 230 driver
Price: $500 with Project X HZRDUS Smoke Green RDX, Mitsubishi Lai’ Li Blue or UST Mamiya Helium NanoCore 4F1 shaft and Lamkin ST Hybrid grip
Specs: 460-cc head with a forged titanium face and chassis, carbon fiber crown and sole panels, and adjustable hosel. 9.5, 10.5 and 12-degree head options.

Who It’s For: Golfers who prioritize forgiveness and who want to hit straighter drives.

The Skinny: The new ST-Max 230 takes the weight saved by using a large carbon fiber crown and sole panel and redistributes it to the back of the head to boost the forgiveness and make the club Mizuno’s most stable driver.

The Deep Dive: Just as you can tell a lot about a man by the quality of his shoes and belts, you can tell a lot about a driver by observing where designers and engineers position weight in the head. Mizuno’s ST-G driver has more weight concentrated in the front, which helps it reduce spin and put an emphasis on ball speed. The Japanese company’s newest driver, the ST-Max, utilizes an entirely different design, materials and weighting concept, and the result, according to Mizuno, is its most stable and forgiving driver.

In the address position, the ST-Max looks bigger and wider than the other ST drivers, even though its 460-cc size gives it the same volume as the ST-Z and ST-X drivers. It has a lower profile but is larger from heel to toe and from front to back, and when it comes to stability, bigger is better.

The key to increasing the moment of inertia (MOI) and making a club less likely to twist on off-center hits is to position more weight in the back of the head. To do that in the 460-cc ST-Max, Mizuno designed the club with a massive carbon fiber crown and increased the size of the carbon fiber sole panel. Replacing titanium with carbon fiber reduces weight, and that saved weight was put back in the head by adding a 54-gram weight to the very back of the head. Having that much mass concentrated in the rear of the club keeps it moving forward and wobbling less on mis-hits, which should result in straighter drives.

The ST-Max 230 has a forged face made from Beta Rich Ti LFS titanium. (David Dusek/Golfweek)

To increase ball speed, Mizuno opted to use the same Beta Rich Ti LFS titanium in the face that debuted in the ST-G driver. It is lighter and has a higher tensile strength, so the multi-thickness face can flex more efficiently while maintaining durability.

Mizuno also increased the size of the CorTech Chamber, which is behind the leading edge in the sole. Mizuno has used this technology in recent drivers, and it involves creating a slot in the sole and then filling it with thermoplastic polyurethane (TPU) to keep water and debris from getting inside the head. Inside the TPU, Mizuno adds a stainless steel bar, so while the soft TPU material allows the lower portion of the face to flex more efficiently on low-struck shots, the bar helps the head maintain momentum. The TPU material also soaks up excessive vibrations and enhances sound, so drives feel and sound better.

Below are several close-up photos of the Mizuno ST-Max driver.