Srixon ZX Irons: Mainframe Goes Mainstream

Srixon ZX Irons – Key Takeaways

• The new Srixon ZX lineup replaces the highly successful Z85 series.
• ZX7 is a one-piece forged cavity back for better players; the ZX5 is a multi-piece iron for distance and forgiveness.
• The updated ZX utility is more streamlined than the Z85 utility while still keeping the center of gravity low.
• Srixon’s computer-driven Mainframe technology designed variable thickness face for the ZX5 and ZX utility.

There’s a clear and present challenge for the new Srixon ZX irons: When you have a powerhouse iron lineup like the Srixon Z85 series, how do you make it better? Can you realistically improve on one of the best game improvement irons, one of the best player’s irons and one of the best utility irons of the last half-decade?

After all, if it ain’t broke, don’t fix it. Right?

Srixon’s Z85 line has completed its two-year mission. And while the Z585 copped Most Wanted Game Improvement iron in 2018 and was still a top runner-up in 2020, some were turned off by the looks – specifically, the black poly frame highlighting the back cavity. And even though the Z785 cavity back was also an MGS top performer, many golfers preferred the older Z765 for looks and feel.

Those may be nits to pick but picking nits is at the heart of Srixon’s iron development.

“We don’t jump around significantly from generation to generation,” says Dustin Brekke, Srixon’s Director of Engineering. “There’s two sides to that. On the one hand, you want the brand-new bell or whistle that’s going to give you big marketing bullets. But at the same time, you just want to tweak what’s really needed. It allows for improving the design for each generation rather than wildly swinging from design to design.”

The new Srixon ZX5 is the replacement for the Z585 while the ZX7 is an update for the Z785. And the ZX utilities represent an interesting upgrade over the very popular Z85 series. And much of what’s new can be chalked up to what Srixon is calling Mainframe.

Srixon ZX Irons: AI + HI = MF

A.I. (artificial intelligence) is quickly becoming the bedrock of golf research and development. A powerful computer and intelligent software allow designers to iterate thousands of different design possibilities quickly. The likely outcome may very well be something a team of engineers would never have been able to consider.

But the machines haven’t taken over yet.

“If our strategies are inefficient, the most powerful computer in the world won’t get you where you want to be,” says Brekke. “That’s where the human interface (H.I.) comes in. I won’t let the computer go too far in one direction because I know the result will feel terrible and you’ll have a clicky sound.”

“We’re a ways away from saying, ‘Hey, computer, here’s a club head and here’s a goal – maximize ball speed’,” he adds. “What we’re doing is combining artificial Intelligence with Human Intelligence. We still want a clean look and a nice sound and feel. We don’t want it going wild and looking at solutions that really aren’t solutions.”

For the Srixon ZX irons, the result of the A.I. and H.I. collaboration is called Mainframe. It’s a unique variable thickness face design Srixon says maximizes ball speed no matter where you hit it on the face.

In non-marketing speak, that means minimizing ball speed loss on off-center strikes, but you get the idea.

Srixon ZX5 Irons

Of the Srixon ZX iron lineup, the ZX5 is on the better-player side of the game improvement category. They share plenty of DNA with the Z585s but there are enough differences to matter.

The biggest is the Mainframe-designed face. Specifically, it’s a variable thickness pattern of grooves, channels and cavities co-designed by Srixon’s A.I/H.I. team and pressed into the back of the face. The idea is to make the face as thin and as fast as possible while optimizing the pattern to maximize ball speed where golfers are most likely to hit it.

“If a player hits it toward the toe x percent more than on the heel, you want to weigh that more intelligently in your design decisions,” says Brekke. “In our optimization model, we can consider impact variation and adjust our design to best optimize the overall average, not just your center face average.”

The ZX5, like the Z585 before it – and even going back to the Z565 – features a forged 1020 carbon steel frame with a face made from high strength SUP10 steel.

“We’ve been using it for several iron generations and we continue to refine its capabilities,” says Brekke. “When you go chasing new materials, you might run into manufacturing issues that end up watering down or completely washing out any gains you thought you were achieving through some textbook numbers.”

SUP10’s strength-to-thickness ratio makes it ideal for Mainframe.

“You couldn’t do Mainframe with 1020 carbon. You’d need a massively thicker face,” says Brekke.

So, while the body is forged, the part you actually hit the ball with isn’t.

“The densities are similar but you have different needs,” says Brekke. “You need high strength in the face and you need bendability and vibration absorption in the hosel. Two-piece construction lets you optimize both of those.”

Progressive Groovy Sole Power

Srixon is introducing progressive grooves in the ZX series. We’ve seen it in wedge design: 46- through 52-degree wedges with wider grooves better suited to full shots and 54-degree and up with narrower grooves better suited for partial shots. Srixon is doing the same thing – only different – with the new ZX irons.

“With long irons, we’re going for distance and consistency,” says Brekke. “In short irons, we’re not worried so much about distance or maximizing face hotness. We want consistent spin out of the rough or in wet conditions.”

Specifically, the 3-  through 7-iron grooves are wider, shallower and farther apart. That allows Mainframe to make the face as thin as possible without compromising durability.

The 8-iron through pitching wedge grooves are deeper and narrower and there are more of them. Brekke says it’s more of a wedge groove spec to enhance spin.

Srixon is also going back to the future with its Tour V.T. Sole. The Z25 and Z45 models featured sole notches on the heel and toe. Those were absent in the Z65 and Z85 models but are back for the ZX series

“The notches are for drag,” says Brekke. “More so on the heel when a player’s hands get a little low at impact or if the club hasn’t dropped all the way down. We put a little more bounce into the leading edge of the V sole but we don’t have to continue down to the heel and toe.”

One thing you can say about Srixon’s turf interaction: shots you swear were hit fat still fly.

“That’s the extra bounce on the leading edge,” says Brekke. “You’re not going to dig in and lose head speed. And the trailing edge of the Tour V.T. Sole helps you get through the rest of the turf.”

Srixon ZX7 Irons

It’s hard to make any significant changes in a one-piece forged cavity back. It’ll take a discerning player to notice substantive differences between the new Srixon ZX7 and the previous Z785, but they’re there.

First off, the ZX does not have Mainframe technology. It’s a one-piece 1020 carbon steel forging and, as mentioned earlier, 1020 carbon steel isn’t compatible with the Mainframe process.

“ZX7 is more focused for center face impact for better players,” says Brekke. “It has added mass behind the ball for better and more consistent feel at that impact location. Those benefits far outweigh what a two-piece design could ever do for that player.”

Added mass at the point of impact comes at a cost, however, since that mass has to come from somewhere. It’s usually the perimeter and taking away perimeter mass sacrifices forgiveness. That’s where the toe tungsten comes in.

“Tungsten is always something you wish you could use more of,” says Brekke. “For the ZX7, we reduced the blade length just a touch (compared to the Z785), which is something Tour players wanted. But that sacrifices heel-toe MOI, so we put tungsten out on the toe to keep the performance numbers up.”

The Srixon ZX7 is also noticeably more bottom-heavy than the Z785, with what looks like a shelf or bridge at the very bottom.

“If you hit it high on the face, the club is going to want to rotate backward and you’re going to add loft,” says Brekke. “We want to move mass as far away from that as possible.”

“You can only change so much. Finding the ways to shape within a very small design space becomes the challenge. It’s all very deliberate.”

The ZX7s are also getting the same progressive groove update as the ZX5s, along with the same updated Tour V.T. Sole.

Srixon ZX Utility Irons

Srixon’s ZX utilities are getting perhaps the biggest upgrade from the Z85 models. The new ZX utilities get the full Mainframe face upgrade but the thing you’ll notice most is there’s considerably less junk in the trunk.

“We made it more compact from face to back to eliminate the distraction of seeing the back muscle on your 2- or 3-irons,” says Brekke. “It’s definitely a narrower sole and chassis width so you don’t see the backside at address behind the topline.”

Any time you change the basic geometry of a club, you have to deal with unintended consequences. By making the chassis narrower, CG starts to creep up, which impacts MOI, gear effect and overall performance. To keep CG low enough, Srixon added tungsten weighting to the ZX utility sole.

In addition, Srixon was able to slim down the top line so it’s only two millimeters thicker than those of the ZX5 and ZX7.

“The design game is how to invisibly hide weight and how to invisibly control weight,” says Brekke. “That’s from the player’s perspective, and the topline has some visual trickery with a chamfer you don’t really see at address.”

Srixon actively promotes the idea of mixing and matching irons into any combination of utilities, ZX5s and ZX7s that suits your game. However, both the sole width and offset of the utilities indicate they’re a better match with the ZX7s.

“That’s the most expected combo,” says Brekke. “They’re all very similar but the finer view is we’re definitely looking to pair the utility irons with the ZX7, and giving that player an easy transition if he’s stepping into the utility after his 4- or 5-iron. The ZX5 player is more likely looking to transition to a hybrid.”

Specs, Pricing and Final Thoughts

The Srixon ZX irons are the only major OEM offering the Nippon N.S. PRO Modus3 Tour as its stock iron shaft. The ZX5 is more of a better player’s game improvement iron and features the lighter PRO Modus3 Tour 105 in both R flex (103 grams) and S flex (106.5 grams). The UST Mamiya Recoil 95 is the graphite option. Both manufacturers categorize those shafts as mid-launch. The Golf Pride Tour Velvet 360 grip is stock.

The ZX7 features the heavier and lower launching PRO Modus3 120 shaft as stock in both S flex (114 grams) and X flex (120 grams). There is no stock graphite offering. Again, the Golf Pride Tour Velvet 360 is stock.

The loft structure of both the ZX5 and ZX7 isn’t what you’d call traditional but they aren’t what you’d called “jacked”, either. They are, in fact, unchanged from the Z85 lineup.

The ZX utility irons will be available in 18-, 20- and 23-degree lofts to replace your 2-, 3- and 4-irons.  The UST Mamiya Recoil is the stock shaft (R, S and X flex). You’ll note Srixon is not offering Miyazaki as its stock graphite shaft in the ZX series. Srixon’s parent company also owns Miyazaki but when it comes to retail, you have to play the shelf appeal game. We saw this in 2018 when Srixon offered the Project X HZRDUS Black and Red as stock offerings in the Z85 drivers.

Lefties rejoice! The entire Srixon ZX irons lineup is available for both sides of the plate.

The ZX5s and ZX7s will retail for $1,299.99 in steel (eight-piece sets) or $162.49 per club. The ZX5 in graphite will sell for $1,399.99 (eight-piece set). The ZX utility irons will retail for $219.99 each.

Presale starts Jan. 6 on Srixon’s website, while the full retail launch is set for Jan. 15.