You measure a golf club shaft primarily by checking its length, stiffness (flex), and how it twists (torque). These measurements help determine how the shaft performs for a golfer.
Measuring a golf club shaft is vital for fitting and performance. A proper shaft matches a player’s swing speed and style. If the shaft is wrong, it can hurt distance and accuracy. We look at several key traits. These include its length, how stiff it is, and how it twists. Getting these numbers right helps build the perfect club.
Shaft Length: The Basics of Club Sizing
Shaft length is the most basic measurement. It directly affects how the golfer sets up. It also influences where the ball strikes the clubface.
Standard Measurement Method
To find the standard length, you need a reliable measuring tool, like a steel tape measure. You must hold the club straight against a wall or a dedicated measuring device.
How to Measure Length:
- Place the club heel squarely on the floor.
- Measure straight up the back edge of the shaft.
- Stop measuring at the top end of the grip cap.
This measurement tells you the club’s overall length. This is crucial for consistency across a set. Different irons and woods have standard length ranges. Adjustments are common in custom fitting.
Determining Golf Shaft Flex Measurement
Shaft flex is perhaps the most debated measurement. It describes how much the shaft bends during the swing. This bending is key to shot height and ball speed. A proper golf shaft flex measurement ensures the club releases energy correctly.
Frequency Testing Golf Clubs
The most common and accurate way to check stiffness is through frequency testing golf clubs. This method measures the shaft’s natural vibration rate in cycles per minute (CPM).
The Process of Frequency Testing:
- Mount the Club: Clamp the club securely at the hosel area (where the shaft meets the head). Leave about 1 to 1.5 inches of the butt end sticking out.
- Strike the Shaft: Gently tap the butt end of the shaft with a small metal rod or hammer. This makes the shaft vibrate.
- Measure the Cycles: A specialized electronic device reads the vibrations per minute. This is the CPM reading.
Higher CPM means a stiffer shaft. Lower CPM means a more flexible shaft.
| Flex Designation | Typical CPM Range (Irons) | Associated Swing Speed |
|---|---|---|
| Ladies (L) | 210 – 230 | Slow |
| Senior (A) | 230 – 245 | Medium-Slow |
| Regular (R) | 245 – 260 | Medium |
| Stiff (S) | 260 – 275 | Medium-Fast |
| Extra Stiff (X) | 275+ | Fast |
This data helps us perform golf club shaft stiffness analysis.
Relating CPM to Shaft Bending Properties
The CPM test gives you a number, but shaft bending properties describe how it bends. A shaft can have the same CPM as another but bend differently. This comes down to design and material.
Factors affecting bending properties include:
- Tip Stiffness: How the clubhead end behaves during impact. Stiffer tips promote lower ball flight.
- Butt Stiffness: How the handle section feels. Stiffer butts offer more control.
These properties are closely linked to where the shaft is designed to kick.
Locating the Kick Point (Bend Profile)
The kick point, or bend profile, is where the shaft bends the most during the swing. It greatly affects launch angle.
Shaft Length and Kick Point Interaction
It is important to note the relationship between shaft length and kick point. Cutting a shaft changes its effective kick point. Cutting the tip makes it stiffer overall and raises the kick point slightly. Trimming the butt end generally lowers the kick point slightly and reduces overall stiffness.
Professional fitters use specialized bending equipment to test this. They place weights on the shaft tip and measure the deflection. This is often called testing golf club shaft deflection. A shaft that deflects easily near the tip has a low kick point.
Measuring Twist: Golf Shaft Torque Rating
Torque measures a shaft’s resistance to twisting during the swing. This resistance is measured in degrees. High torque means the shaft twists easily. Low torque means the shaft resists twisting more.
A golf shaft torque rating is crucial for golfers who release the club face aggressively.
Torque and Golfer Type:
- High Torque (e.g., 4.5 degrees or more): Tolerates off-center hits better. Often preferred by slower swingers.
- Low Torque (e.g., 2.5 degrees or less): Offers maximum control for fast swingers or players with consistent impact.
Low torque shafts are common in blades and driver shafts aimed at professionals. High torque shafts are often found in game-improvement irons.
Analyzing Swing Weight vs Shaft Flex
Many people confuse shaft flex with swing weight. They are separate measurements, but they work together.
Swing weight vs shaft flex shows how the club balances. Swing weight measures the balance point relative to the butt end. It uses a standardized scale (A-F, with sub-increments).
- Shaft Flex relates to bending stiffness (CPM).
- Swing Weight relates to balance point and overall feel.
A stiff shaft (high flex) can feel lighter if the overall swing weight is low. A soft shaft (low flex) might feel heavy if the swing weight is very high. Both must be right for a comfortable swing.
Advanced Measurement: Shaft MOI Matching
Modern club building focuses heavily on Moment of Inertia (MOI) matching. This technique aims to make every club in the bag feel the same in hand, even if they have different lengths or head weights.
What is Golf Club Shaft MOI?
Golf club shaft MOI measures a shaft’s resistance to being rotated around its long axis. It is a measure of mass distribution along the shaft length.
If you match the MOI of all clubs, the golfer feels a consistent swing weight, regardless of the iron number. This relies on precise measurements of shaft weight, grip weight, and head weight.
Steps in MOI Matching:
- Determine the target MOI for the set.
- Assemble the driver and measure its MOI.
- Assemble each subsequent club (woods, then irons, then wedges).
- Use tip weights or butt weights to adjust the assembly until the MOI matches the target standard.
This contrasts with traditional swing weight matching, which can lead to inconsistencies in feel as shaft lengths change.
Measuring Shaft Profile (Straightness and Taper)
Shaft performance also depends on its physical shape, known as the profile.
Straightness Check
Shafts should be straight. Even minor bends can cause wobbling during the downswing.
How to Check Straightness:
- Remove the grip and head if possible.
- Roll the shaft gently on a perfectly flat glass or granite surface.
- Watch for any sections that lift off the surface as you turn the shaft.
Modern manufacturing makes bent shafts rare, but this is a good check for used clubs.
Taper Measurement
Shafts taper (get narrower) from the butt end to the tip. This taper affects stiffness.
- Tour Parallel (Parallel Tip): Common in iron shafts. The tip section is parallel for a certain length before tapering begins. This allows fitters to easily change length without changing the flex or kick point significantly.
- Stepless/Continuous Taper: The shaft narrows gradually along its entire length. This is common in some driver and wood shafts.
Fitters measure the outside diameter at specific points to map this taper. This information is vital when swapping shafts between different club heads.
The Role of Dynamic Swing Speed Measurement
While static measurements (like length or torque rating) are taken off the club, the most crucial factor is how the player uses the shaft. This requires dynamic swing speed measurement.
Dynamic measurement happens while the golfer is swinging the club. Sensors measure the speed of the clubhead at impact.
Why Dynamic Measurement Matters:
- Flex Selection: A player might have an average measured swing speed of 90 mph, suggesting an ‘R’ flex. However, if their tempo is very quick (aggressive transition), they might load a stiff shaft better.
- Torque Confirmation: Fast transition players often need lower torque, regardless of the measured swing speed, to maintain face control.
Modern launch monitors (like TrackMan or Foresight) provide this dynamic data accurately. This feedback loops back to the static measurements, confirming if the chosen golf shaft stiffness analysis matches the player’s real-world action.
Assembling the Data: Finalizing Club Specifications
Measuring all these components—length, flex (CPM), torque, and MOI—allows a club builder to assemble or modify a club precisely.
Key Combinations to Verify:
- If the desired launch angle is low, ensure the shaft has a high kick point and a relatively low tip deflection rate.
- If the player struggles with slices, confirm they are using a low-torque shaft to maintain face control.
- Ensure the swing weight vs shaft flex combination feels comfortable for their tempo. Too heavy a swing weight with a soft shaft can cause ballooning shots.
Accurate measurement is the foundation of performance fitting. It moves golf club assembly from guesswork to engineering.
Frequently Asked Questions (FAQ)
How is golf shaft torque rating typically expressed?
Torque rating is usually expressed in degrees, commonly ranging from 1.8 degrees (very low torque, very stiff) to over 5.0 degrees (high torque, more flexible twisting).
Can I change the flex of a shaft just by cutting it?
You can change the effective stiffness, but you don’t change the inherent golf shaft flex measurement (CPM) of the material itself. Cutting the tip makes the remaining shaft stiffer. Cutting the butt end makes it slightly softer overall and changes the kick point location.
Does shaft length affect kick point?
Yes. Shaft length and kick point are linked. Shortening the shaft generally raises the effective kick point and increases overall stiffness. Lengthening the shaft lowers the effective kick point and decreases stiffness.
What is the importance of testing golf club shaft deflection?
Testing deflection helps map the specific bending profile of the shaft, independent of simple CPM readings. It shows exactly where the shaft bends most easily, which is key for determining launch characteristics.
How often should I check my shaft stiffness?
If you are a dedicated player, checking your CPM every few years is wise, as shafts can soften slightly over time due to repeated impact cycles. If you notice significant performance changes, measure the shaft immediately.