This isn’t where I tell you what a birdie means or what a bunker is. Chances are you already know that or you wouldn’t be reading this blog. But I am here to help you break down what some of the more tech terms are when it comes to golf equipment and getting fit or finding your next club; because that’s the side I come from and I use a lot of these terms in the blog and our website in product descriptions. You have certainly probably heard of all of these, and some you maybe were never quite sure what they meant or what they referred to. Aerospace engineers now design golf clubs. I just sell them. These terms are uniform and will never change, so this write-up should age well and be a good frame of reference for years to come. Don’t worry; there won’t be a quiz after. But you’ll be in better shape next time you read an article or go to a golf shop.
MOI, Moment of Inertia This refers to a club’s resistance to twisting at impact, usually a driver. The higher the number the more stable the clubhead is. When a ball is struck anywhere on the face besides the sweet spot, simple physics take over and the face wants to twist in either direction. This results in a loss of power and accuracy. A high MOI is usually achieved by the strategic placement of weight in the head. Simply put, the greater the MOI, the more forgiving the club.
CG, Center of Gravity This goes hand in hand with MOI as the placement of the center of gravity can greatly affect a club’s MOI. The lower the CG, the higher launch and the higher the ball will travel. A mid CG, or directly behind the ball at impact, will promote a mid launch. And you guessed it; a high CG will promote a lower launch and trajectory.
CC, Cubic Centimeters The headsize of drivers, fairway woods, and hybrids is measured in cc’s. You’ll notice that almost every driver on the market is 460cc. This is the legal limit set by the USGA in 2004. You may see an off-brand put out a 500cc or 600cc driver, but you won’t find it on the conforming list and it’s probably junk.
Launch Angle This is the degree of the angle your ball leaves the clubface at impact. Loft determines this more than anything but so does attack angle. There is no perfect number to strive for here but there is an ideal launch angle we want to achieve depending on the player. For instance, for an average player with a swing speed around 95 mph, I try to get them between 10° and 13° of launch with a driver. This is in combination with their spin rate as well to maximize their carry distance.
Spin Rate RPM This refers to the backspin on the golf ball in rotations per second. The more spin the higher it flies and the softer it lands. Great for a wedge…bad for a driver. But you need enough spin to keep the ball in the air. Again, every player is different but I strive to get the average player to produce between 2500 – 3000 rpm’s of spin with the driver. This is achieved through the combination of loft, shaft, and technique. Players with fast swing speed are naturally going to generate more spin. A junior, female, or senior player with a slower swing speed will need to increase their spin with club and shaft choice in order to keep the ball in the air and ensure it carries. When it comes to irons however, there is a number we look for with each club and it’s nice and simple; the first number matches the iron you’re hitting. We’d like to see a 7 iron spin around 6500-7000, a 4 iron 3500-4000, a 9 iron 8500-9000, etc. We want you to hit your irons as far as possible while still promoting a trajectory that allows the ball to land softly and hold the green.
Ball Speed Simply how fast the ball leaves the clubface measured in mph (miles per hour). The average ball speed among amateurs with a driver is 130 mph. The average on tour is 180 mph. Bryson DeChambeau made waves in 2020 by reaching 200 mph.
Smash Factor This is a sought after number when being fit on a launch monitor. The formula is ball speed divided by swing speed. The goal is to be on or around 1.50. Player A just hit a drive with a clubhead speed of 106 mph and a ball speed of 152 mph. 152/106 = 1.43 smash factor.
Kick Point Not every shaft performs the same. I can hand you 3 shafts that are all 3 stiff flexes and each will perform and feel differently. The kick point, or flex point of the shaft is the location point at where the shaft flexes. This determines the launch and trajectory at which the ball will travel. A low kick point will launch the ball high, a mid will launch it at a mid trajectory, and a high kick point will launch the ball low.
Torque Again, not all shafts are created equal. Torque relates to the shaft’s resistance to twisting at impact. Shafts are round, so not just twisting side to side, but up and down, and around. A low torque shaft will feel very stout and play stiffer, where a higher torque shaft will feel more flexible and play softer. I could hand you 2 regular flex shafts and one will feel much stiffer. That shaft could have a torque of 3.2° and the other could be a 4.5°.
Blade A blade is an extremely difficult iron to hit consistently as they are not very forgiving and boast a small sweet spot. Miss-hits feel terrible and fly extremely offline due to the amount of sidespin put on the ball. However nothing in golf, or life for that matter, feels like a well struck forged blade. This is why only the game’s best players game a blade. They want to work the ball in either direction, and you can work the ball without creating sidespin. But only 2% of card-carrying PGA Tour players play blades. They want some forgiveness too. They usually play a muscle back or an iron that’s grown in popularity…a forged cavity-back.
Muscle back A muscle back iron is played by the games’ best and looks like a blade at address. While still forged in construction, they feel similar when hit well. But a muscle back will have some added material and weight to the back directly behind the sweet spot. This adds a little forgiveness and a better feel on shots that miss the middle.
Cavity back A cavity back is the most forgiving iron and falls in a category we like to call “game improvement.” They are typically larger in size with an expanded sweet spot. Miss-hits will fly straighter, higher, and feel much better. The cut out cavity saves weight and allows that weight to be placed low in the sole and around the edges. This is referred to as perimeter-weighting. This keeps the face more square at impact and thus reduces side spin on poorly struck shots. Scratch players or pros want to shape the ball in flight and these are designed to hit it high and straight. Not a bad recipe for 99.9% of you.
Urethane This material is a popular choice among engineers when designing both golf clubs and golf balls. Urethane is strong and dense but provides an exceptional soft feel. It is added to club heads to increase ball speeds all while delivering a super soft feel at impact. Same reasons for putting it in a golf ball.
Multi-layer You will read the term “multi-layer” when reading about the design elements of clubs and balls. A multi construction ball refers to the layers and the core. When you read about a 2-piece golf ball know they are referring to a ball with a core and a single layer…2 pieces. The more layers or construction a ball has, the more it will spin and the more performance elements it possesses. A 2-piece ball will be distance oriented and won’t spin much into the green, but it may feel soft due to the cover. A 4-piece like a Titleist Pro V1 or a 5-piece such as a Taylormade TP5 will fly higher with shot-shaping capabilities and spin a lot on approach shots and chips.
There are a lot of pieces and materials that come together to make a high-performance driver. A lot of today’s models feature a carbon-composite crown fused with a thin and high strength titanium face and sole. Tungsten weights are then added to position the CG in a way to achieve the ball flight they’re after. Building the body of carbon saves a lot of weight because it’s lighter than titanium and just as strong. But you don’t get the ball speed or “trampoline effect” so the face still needs to be steel or titanium. Wilson Staff constructs the crown of their new D9 driver from Kevlar. This material is used in bulletproof vests and aircrafts. I told you aerospace engineers were designing golf equipment!
Bounce This is a term you’ll hear when talking wedges. What the hell is it and why is it important? Bounce refers to the degree of the gap between the turf and the leading edge of the sole. Wedges not only come in a variety of lofts and now sole grinds, but also multiple bounce angles. That is the 2nd number next to the loft stamped on the head. The lower the number, like 4 or 6, the lower bounce. Which means the wedge lays sharper against the ground with very little gap. The middle number, like 8 or 10, is well…….middle. And high bounce, like 12 or 14, means the gap is the largest.
Which bounce should you play? Two variables come into play when answering this question…playing conditions and attack angle. If you have a very steep downswing and take a deep divot, you should play higher bounce wedges. If you come into the ball very shallow and pick the ball pretty clean with little to zero divot, you need low bounce because they will dig in more. And if you’re somewhere in the middle with a normal sized divot, well…you’re boring and standard bounce is good for you. Tour pros change their sole grind and bounce based on where the tour takes them that particular week and what conditions they’ll be facing. But unless you’re completely nuts, you don’t change out your wedges based on what course you’re playing. Low bounce wedges are good for firm conditions. A course with a lot of hardpan and dry, packed sand. High bounce is good for very flush conditions; thick, lush grass and powdery soft sand traps. In northeast Ohio you can get all 4 seasons within 24 hours so it’s difficult to pick based on conditions. I’ll play a private club with lush conditions one day and a hardpan muni the next day. Pro tip: When choosing wedges please remember that bounce is your friend when it comes to getting out of bunkers. The bounce is what is actually striking the sand first and a high bounce will glide easily and splash your ball out more efficiently. So if greenside bunker play is your weakness, remember this when buying your next wedge that you will play most of the time with these types of shots, whether it is a 56° or 58°.
Fantasy Picks The Waste Management Phoenix Open is always a breath of fresh air and it’s usually because of the 20,000 rowdy fans at the par 3 16th hole. This year it was also because of the fans, but only 5,000 were let in. A step in the right direction as it was awesome to see…and hear! When Brooks Koepka chipped in for eagle on 17 on Sunday is was refreshing to hear a gallery roar and see a fist pump. A reminder of what was and hopefully of what’s to come as tournaments begin to allow spectators on a small scale. Rory played well and snagged a T-13, and Steele and Simpson both made the cut but didn’t contend. We head to beautiful Pebble Beach and a much different tournament this year. This is no longer a pro-am as amateurs won’t be competing and the field is kind of weak. Winner Jordan Spieth He’s the brightest star in an otherwise weaker field, and a 61 last Saturday and a share of the lead on Sunday restored that star status. Will Contend Paul Casey Plays well on great courses and in crappy weather. Sleeper Kevin Streelman A gritty fighter and good ball striker who can play well on Pebble because it’s not the longest course in the world. Plus, I’d love to see a Wilson Staffer win.
Enjoy the game and each other,
Seth Zipay – Head Golf Professional