As we move into the new year, I thought it would be best to give a refresher on some of the basics of club design and fitting specs. Appropriate because we manufacturers spout off about Ai, 10K, high MOI, low & deep CoG, etc., and it is often received with a blah, blah, blah. It might be nice to have a refresher course as this stuff comes into view. I have done this at the start of the last couple of seasons, but this is updated with the newest terms.

At this time of the year, every OEM pulls the sheet back off their new product line. To describe it to the public, we use all the techie terms. If you’re not familiar with what they mean, how to interpret them, and how to discuss them, it will be difficult to carry on a conversation about any of the new stuff. So, this week, let’s start with a few terms.

Ai

Ai is a design tool. It stands for Artificial Intelligence. In essence, it’s utilizing the power of a computer to accelerate the design process with input from human and data sources. It allows engineers to “think” outside the box – literally. At Callaway, we started using Ai in 2009, yet our first production club that used it in it’s design was the Epic Flash that launched in 2019. We spent 10 years playing around with this technology trying to figure out what to do with it. We have been using it longer than anyone else in this industry.

As a real world example, the face on the original Rogue driver was designed by an engineer and had 6 different versions before they finally settled on one face for the entire product line. The next driver model was Epic Flash. Using Ai, the team went through 14,000 different faces before finding the right one. This only led to a discovery that the face on the 9* head did not work (at all) in the 10.5* head since the face was so specifically designed for the body that the face sat in. So, the process restarted for each loft and model. 6 different face options to 14,000. That’s progress!!

Today, we use Ai to design faces (and many bodies) on every club we make – including putters with the Ai One. The Paradym Ai Smoke driver face went through roughly 50,000 face designs before coming up with the finished product. We have added optimization for every launch condition into our Ai programming, and, with Ai Smoke, we started to add player golf swings into the data that we use for design.

14,000 faces to 50,000 faces. That seems like a lot and it is. It seems like a big increase. It is, but it’s needed because the complexity of what we feed in to the Ai system requires more trial and error to get it perfect. “But how do you know when you’re done? How many face iterations is enough?” There is a point of diminishing returns. At some point, the design either can’t get any better, or it doesn’t look right, or it exceeds the capabilities of todays manufacturing. Design for the future is still dependent on what else we can do today. The USGA limits how much we can do. And… that finicky “golfer’s eye” – if it doesn’t look like a club that players find appealing, players won’t play it. We need some human intervention to keep the Ai on track. All of these will limit the ceiling of Ai – at least for today.

With Ai, though, simply having the computer power is not enough. It’s like fitting with a launch monitor if you don’t know what you’re doing – having all the information is meaningless unless you know what you’re looking for and how to use it. We are 15 years in with Ai. Ai helps our team be the absolute best it can be.

Ai 10x face

OK. Buckle your seatbelt. This is on all of the new Elyte Drivers. With Smoke, we used AI to design a face that was optimized where players hit it, and where they mis hit it. Why limit it to that? Why not utilize Ai technology to make the face sweeter from every spot- literally? For Elyte, we did it. Smoke had 1500 micro sweet spots on the face – each designed to provide some ball flight correction if the ball is struck there. Elyte has a 10X face. This means there are 25,000 micro sweet spots on the Elyte face (we’re not so good at math – an AI 16.6x face doesn’t have that nice ring in the marketing department, haha). A player will not be able to find a spot on the face that has not been enhanced by Ai.

CoG

CoG stands for Center of Gravity. Typically, the lower we can make it, the higher the ball will fly. Also, the deeper we can make it (how far back from the club face), the more forgiving it is. With some players, we want as low and deep of a CoG as we can get (higher handicappers, players who struggle to get the ball in the air, and players who can’t consistently hit the center of the club face). While with others, we want the opposite (Higher, forward CoG) – think tour caliber player. There are many clubs throughout the line and each one has a different CoG location. Understanding this helps you put the right club in a players hands.

If the CoG gets too far back, the feel is soft or muted – not desirable for a good ball striker. Too far back will also reduce the efficiency of energy transfer to the golf ball (read slower ball speeds). Position here is critical for the feel and performance of the club head. This is the fundamental trade off in club head design – feel vs. forgiveness. As one goes up the other goes down – ALWAYS. Elyte has unlocked this, and now a player can have both.

MOI

MOI stands for Moment of Inertia. Essentially, it measures a body’s resistance to twisting. The higher the number, the more the body resists twisting. The USGA restricts how high the MOI can be for a club.

Why is this number important? If you hit a ball on the TOE of the club, what happens to the face? It wants to open, right?? This opening will start the ball more offline, correct? It’s the equivalent of hitting a shot in the center of the face, but with an open face. Spins will be different, of course, but that’s a different discussion for a different day. If we (manufacturers) can increase the MOI of a clubhead, we can keep the club from twisting as much on off center hits. This is a feature that allows a shot to travel straighter when hit off the center of the face. For certain player groups, this can be VERY important, while for others, it isn’t even worth a mention.

We see this spec discussed mostly in drivers and putters, but it comes into play in everything. It can go too far, though. Too high MOI and the head becomes difficult to release or rotate. Different levels for different player types.

As you look through the new product catalogs, you can begin to question “why would they do this or that?”. As you think critically, you can say “Oh, they did this to increase the forgiveness (as in the larger footprint of the Elyte X Driver). Bigger footprint = more mass out around the perimeter and further away from the ball = a wider and deeper CoG = more forgiving. Perhaps feel will suffer a little? I’ll have to try it and see what I feel.” Very good!! Or I love the taller/ deeper face on the Triple Diamond head. “Why did they do that? Hmmm. It’s not as deep. so the mass (CoG) has to be more forward. It’s taller, so the mass (CoG) has to be higher. It has a smaller footprint, so the MOI must be a little less – maybe not as forgiving. I bet it feels really good, though…” Now you’re getting it!!

10K MOI

With everything, we have to ask the questions – how much is too much (or enough)? And, can we take it too far? MOI is no exception. I mentioned above that the USGA regulates MOI. While we manufacturers can make a 12K driver, the USGA says 10K is enough.

Every company feels that there is an optimal amount of MOI. Every company feels that number is different – similar, but different. MOI is one of those specs that is self-regulating. Companies will find that in their designs; to get optimal performance, some level of high MOI is required, but it is always less than 10K. It could be near 10k.

Callaway has been tinkering with 10K MOI for over 5 years. We can do it – we choose not to. We’ve found that the increase in forgiveness between 9400 or 9600 and 10,000 is minimal, but the loss in ball speed is noticeable. For us, 10K is a marketing talking point that we don’t need. We can deliver forgiveness in other ways (an AI Face) that delivers better ball speeds.

Remember that MOI restricts a body’s ability to rotate. This means several things. If a player hits the center of the face with it square at impact, minimal MOI is needed. Higher MOI will only make this player hit it shorter since the ball speed transfer will be less. Also, if a player can’t square the clubface, higher MOI will make it harder (since it fights the rotation). MOI is good for off center hits, not open or closed club faces. You could make a very strong case that a higher MOI driver head could be HARDER to hit than a lower MOI club head since it is harder to square it.

So how much is too much? The players ability will tell you. Look at hit location and face and path numbers. If it’s a center strike and a very good face to path swing, MOI will be of little help to that player. This player will hit a lower MOI driver head faster (and longer), which may be more advantageous.

Ever get a player who hits his 10-year-old driver longer than today’s driver? Of course, right?? This player is working against MOI. Today’s driver is designed to be faster and more forgiving. Yesterday’s driver was just designed to be faster. Today’s driver may actually be slower than yesterdays IF the player doesn’t need the forgiveness. So, what to do for this player? Try a triple Diamond. I know he’s a 16 handicapper, but… His speed is being lost in the higher MOI, so try something with less MOI to give him more ball speed. It might be the answer…

A little knowledge is powerful. Use it to your advantage. Think about it the next time you pull a club for a player to hit during a fitting. You’re doing it with a purpose and a reason, rather than a “here, try this one. Let’s see what this does.”

Happy Fitting!!!

Jim Yeager, PGA