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2712 Battleground Avenue, Bay 3, Greensboro, NC Thursday: 10:00 AM – 8:00 PM [email protected]
Carry Lab Golf Greensboro, NC · Opened 2009
Shaft Library

Reading a Shaft Without Reading the Marketing

Everything below is what we measure on the bench and what those measurements mean in practice. No brand rankings, no "this shaft is for high swing speeds" hand-waving.

The Short Version

Four Things Matter

Weight. Where the stiffness sits along the length. How much the shaft twists. How long the finished club ends up. Everything else is a consequence of those four, and the flex letter on the label is a summary of exactly none of them.

Weight Comes First, Always

Shaft weight is the variable that changes the most about how a club feels and how a swing sequences. It affects tempo, it affects how early the hands want to release, and it affects total club weight, which in turn affects how hard you have to work to move it. Get it wrong and no amount of profile tuning downstream will rescue the club.

We bracket weight deliberately wide at the start of a session — often forty or fifty grams apart — because the difference is obvious to almost every player and the direction of travel becomes clear within a dozen swings. Once the band is established, we close in ten grams at a time.

Bend Profile: Where the Soft Part Is

Every shaft has a stiffness distribution along its length. Some are relatively soft near the tip and firm through the middle; others do the reverse. The old shorthand for this was "kick point", which compressed a whole curve into one word and lost most of the useful information in the process.

What we actually do is take frequency readings at several points along the shaft, which produces a curve rather than a single number. Two shafts with identical butt frequencies can have completely different curves, and they will produce completely different ball flights on the same swing.

What the curve tends to do

  • A softer tip section generally launches higher and adds spin
  • A firmer tip section holds the flight down and takes spin off
  • A softer butt section makes a club feel more active and can slow perceived tempo
  • A firmer mid section tends to steady the transition for aggressive downswings

Those are tendencies, not guarantees. The same shaft in two different pairs of hands will not produce the same flight, which is the entire reason fitting exists.

Torque, and Why It Is Usually Third

Torque is how much the shaft twists about its own axis under load, quoted in degrees. Lower numbers resist twisting more. It gets far more attention in marketing copy than it deserves as a primary fitting variable, largely because it is a single easy number to print.

In practice, torque interacts so heavily with weight and profile that fitting to it directly rarely works. Two shafts quoted at the same torque from different manufacturers are frequently not measured the same way. We treat it as a tie-breaker between two otherwise similar candidates, not as a starting point.

Flex Letters Are Not a Standard

There is no industry body defining what "stiff" means. One manufacturer's S shaft can measure the same as another's R, and within a single manufacturer the same letter can vary between models. We have measured shafts that were more than twenty cycles per minute apart while carrying identical letters on the label.

This is why every shaft that goes into a build here gets read on the frequency analyser before it gets cut, and why your spec sheet records a number rather than a letter. Numbers can be reproduced. Letters cannot.

Bench Vocabulary

Terms You Will See on Your Spec Sheet

S-1 Raw Length The uncut length as delivered. Driver shafts commonly arrive at 46 inches, iron shafts vary by model and tip type.
S-2 Tip Trim Material removed from the head end. Stiffens the tip section and raises frequency substantially. Follows a published chart per shaft model.
S-3 Butt Trim Material removed from the grip end to reach playing length. Raises frequency far less per inch than tip trim does.
S-4 Butt Frequency Cycles per minute with the club clamped at the butt and the head free to oscillate. Our standard clamp is five inches.
S-5 Parallel Tip A tip section of constant diameter over several inches, designed to be tip trimmed to set flex within a range.
S-6 Taper Tip A tip that narrows continuously. Sold pre-sorted by iron number and tolerates only minimal tip trimming.
S-7 Balance Point Where the shaft balances along its own length. A higher balance point lets you add head weight without running away with swing weight.
S-8 Frequency Slope The rate at which butt frequency climbs across a set. The number that decides whether your gaps hold.
Weight Bands

Rough Orientation, Not a Prescription

These bands exist to give you a vocabulary for the session. Where you actually land is decided on the bench with your own numbers, and plenty of players sit outside the band their swing speed would suggest.

Common shaft weight bands by club type
ClubLightMidHeavyTypically Decides
Driver40–55 g55–70 g70–85 gTempo and release timing
Fairway Wood50–65 g65–80 g80–95 gControl off tight lies
Hybrid60–75 g75–90 g90–105 gTransition from the long irons
Irons (graphite)55–75 g75–95 g95–115 gTotal club weight and fatigue
Irons (steel)95–105 g105–120 g120–135 gStrike consistency and dispersion
Wedges105–115 g115–130 g130–145 gPartial-shot distance control
A Warning

Charts Are a Starting Point and Nothing More

There is a persistent idea that if you know a player's clubhead speed you can look up their shaft. It has never been true. Two players at the same speed can have completely different transitions, one loading the shaft hard and early and the other applying force late and gradually. They need different shafts, and a speed chart cannot tell them apart.

Everything on this page is here so you can follow the conversation in the bay. None of it replaces putting the club in your hands and measuring what comes off the face.

Independent Sourcing

We Are Not Tied to a Shaft Line

There is no house shaft here and no volume commitment to any manufacturer. If the profile that fits you comes from a small aftermarket brand nobody advertises, that is what goes on your spec sheet.

See the components we work with

Bring a Shaft In and We Will Profile It

Curious what is actually in your driver? Drop it off. Profiling a single club takes twenty minutes on the bench and the reading is yours to keep.