Would you like to hit the golf ball farther and more accurately?
For many golfers, the proposition of hitting longer drives as a result of consistent ball striking amounts to the promised land of golfing greatness.
You can improve your results by getting lessons, going to the gym, or, if you don’t have the patience, buying the latest driver, which promises you more yards than you could imagine.
With equipment, we tend to focus on the technology; however, head technology or the materials used in the construction of the head aren’t the sole factors in gaining you more yards and a better relationship with the middle of the clubface.
Employing the correct golf shaft is critical to success, and the story goes beyond using the proper flex.
We’ve covered the importance of features like shaft weight, torque, kick points, and launch characteristics. However, today, we are going to take a look at one other critically important element, and it’s probably the least known or understood: Elasticity Index, or EI.
So, what is EI, and why is it important to add yards to your game and improve your ball striking?
EI is a way of measuring how stiff or flexible a golf shaft is along its length. It combines the material’s ability to bend and the shaft’s shape to show where it’s soft, firm, or in between.
In an even simpler term, think of EI as a “bending map” of a golf shaft; it shows how easily different parts of the shaft flex when you swing.
Understanding where the bend of the shaft is can have an impact on spin and launch conditions, and getting the right EI will help the shaft load and unload correctly in the golf swing, translating to more energy into the golf ball.
To help you understand more about the benefits of EI, we’ll cover the following areas:
- Understanding The Bend Map - EI Profiles Made Simple
- How EI Profiles Affect Your Game
- Popular Shafts by EI Profile
- Choosing the Right Profile for You
Understanding The Bend Map - EI Profiles Made Simple
If you take any golf shaft, you’ll find there are three distinctive areas to it.
The butt end or grip end is the thickest segment, and, as the name implies, is the end where you grip the club. Moving down, you have the middle segment of the shaft, the last segment is the tip area, which is where the shaft is at its narrowest, with the end being attached to the club’s hosel or hosel adaptor for things like golf drivers, fairway woods, and hybrids.
Designers can bolster any one of these three shaft segment areas, which alters the overall profile and elasticity index of the shaft.
Add more material in the construction of the shaft in the butt end (butt stiff), and the shaft will feel more stable under the golf grip.
Switch to the other end of the shaft, adding more weight to the tip section helps to keep the clubface more stable through impact.
Finally, add more material to the mid-section of the shaft, and you will have a consistent, balanced mix.
So adding more material or strengthening the existing setup at either end of the shaft has a similar effect to where an engine is placed in a car.
If the engine is in the front, the back end of the car is lighter and likely to be more “active”, with the opposite being true if the engine is in the rear of the car.
So what overall impact does moving weight in the shaft have on the type of golf shots you hit?
If a golf shaft is butt stiff, it will feel stable in the hands, giving the impression that the shaft might feel heavier when in reality, it’s not; it simply has less give.
Having that feeling of stability in the grip section lends itself to golfers who aren’t too aggressive in the transition from backswing to downswing.
Looking at the opposite end, if a shaft is tip stiff, it will promote a firmer feel at impact in an effort to maintain control of the clubface. If you look through many “What’s In The Bag” articles about tour players, you’ll often see remarks about the shafts they use being tipped.
For tour players, tipping the shaft further helps negate a big miss left, which many of them fear the most on the course.
Having a mid-section stiff shaft creates a smooth, consistent feel throughout the shaft, making it a popular profile for every level of player.
How EI Profiles Affect Your Game
From a fitting standpoint, we can start to understand how different EI characteristics can work with different types of players.
If you are a golfer who wants clubface control because you like to add or reduce spin and work different shot shapes, opting for a golf shaft that is predominantly tip stiff is the way to go.
Tip stiff shafts also tend to better control excessive spinny ball flights, which, if you are a better player, can go towards maximising your carry distances.
If you are new to golf or play off a higher handicap, opting for a shaft that is butt stiff could prove to be a smart decision. Softer-tipped shafts tend to help get the ball airborne, due to having a little more “kick” at the bottom.
Many golfers fall into the mid-stiff profile. It’s a jack-of-all-trades because it helps deliver power smoothly.
Popular Shafts by EI Profile
At Nine By Nine Golf, we have access to one of the biggest selections of custom shafts anywhere to reflect the fact that we help golfers of all playing abilities get more from their game through custom-fitted golf clubs.
Over the course of this year, we have found the following shafts to be really popular:
- Mitsubishi Tensei 1k Pro Orange
- Graphite Design Tour AD VF
- Aldila Synergy Blue
Mitsubishi Tensei 1k Pro Orange
The Mitsubishi Tensei 1K Pro Orange is built for stronger, faster players who want a stable, powerful feel rather than something soft or whippy. It’s counterbalanced, meaning more weight sits near your hands, which helps some golfers swing faster and control the clubhead better. The shaft feels very firm and solid, especially through the handle.
Because it’s designed to launch the ball low with minimal spin, it produces a flatter, more penetrating flight. Still, it can be unforgiving for slower swingers or anyone who needs help getting the ball airborne.
Graphite Design Tour AD VF
The Graphite Design Tour AD VF is built with a very stiff tip and a firm butt / stiff middle, so it promotes a low-to-mid launch and lower spin. In the hands, it feels solid and stable, and the tip resists twisting hard at impact. On the plus side, that stiffness gives great control and precision, especially for strong players who want to hit tight, penetrating shots.
The trade-off is that it’s less forgiving on off-centre strikes, and slower swingers might struggle to get enough height.
Aldila Synergy Blue
The Synergy Blue is designed for mid launch / mid spin, offering a balanced trajectory suited to many golfers. One of Synergy Blue’s strengths is its forgiveness. Though not ultra-soft, the even bend profile helps it handle minor mishits better than very stiff tip designs.
On the flip side, extremely aggressive swingers or those demanding very low spin might find it a bit too “middle of the road.” Also, for slower swingers needing a higher launch, it may not provide quite the lift they’d prefer.
Choosing the Right Profile for You
Understanding how your swing functions is a good starting point for selecting which EI profile is going to suit you best.
Consider the following questions: are you a player who doesn’t like to rush anything in your swing, opting for tempo being king over everything else in a graceful, Ernie Els-style, or are you trying to knock the cover off the golf ball by going at it as hard as you can in an explosive Jon Rahm-esque fashion?
The second element to consider is what type of shots you like to play, and, by extension, are these shots influenced by the golf course types you play regularly?
What we mean by course consideration is that if you play a lot of links golf, you’ll be used to manipulating your shots to account for the exposed windy environments you face.
If you are used to playing in more serene, inland parkland-style courses, you may favour playing the ball through the air more because it’s less affected by any wind and you need maximum carry distances to fly hazards off the tee and around the greens.
Answering those questions gives you the starting point to shaft profiles that might suit your game, but to fully understand which shaft is right for your game, you need to test, and that’s where custom fitting is crucial.
Custom fitting will provide hard data to analyse the impact of different shaft profiles. Data such as spin and launch rates, along with peak trajectory and point of contact, can be assessed to understand how different shafts perform.
Launch monitor data isn’t the only way to assess what’s right and wrong. Working alongside the fitter, you’ll be able to provide feedback on what feels right to you.
All golfers who come for a fitting, when they are first given a club to try, will feel what the golf club is like in their hands before hitting a shot. This is such a valuable initial interaction with the club because you can feel how the shaft is by employing what we all do: the waggle test.
The waggle test will give you instant feedback on how the shaft feels. We could be forgiven for thinking a shaft might feel whippy during a waggle test when, in fact, it is the tip section that is softer than the rest of the shaft.
Shafts that feel stiff or too light could be butt stiff, and the rest of the shaft is perfectly tuned to give specific flight characteristics.
Coming to Nine By Nine Golf for your fitting also guarantees that the golf shaft you opt for is cut, measured, and fitted using the same machines and processes used on the tour trucks that are seen every week on the PGA Tour and DP World Tour.
Ready to Find Your Perfect Shaft Profile?
There are compelling reasons to pay more attention to your golf shafts. The right bend profile can add distance, improve ball striking, and help you control trajectory more precisely. As the season winds down, it’s the ideal time to assess your setup and prepare for a stronger 2026.
Head to the Nine By Nine Golf website and explore our Custom-Built Golf Clubs section for a complete overview of how custom fitting can transform your game. You can browse our full range of shafts, compare EI profiles, and order directly through our online store, each one built to your exact specifications by our tour-grade technicians.
Prefer hands-on testing? Book a custom-fitting session with us and see the data for yourself. Our team uses the same precision equipment trusted on PGA and DP World Tour trucks to ensure your new setup performs exactly as intended.