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4180 Bardstown Road, Suite 6 · Louisville, KY Bench work by drop-off Wednesdays (502) 555-0173
Eagle Line Fit Louisville, KY · est. 2011

Studio › Shaft Reference

What we actually mean when we say a shaft is too soft

Nothing on this page is a substitute for measurement. It exists so the vocabulary we use during a session is not a foreign language, and so you can tell when somebody is guessing.

0Flex letters we trust
cpmWhat we read instead
30Cycle spread within one flex
$12To measure any club

The letter problem

R, S and X are marketing, not specification

There is no industry standard behind those letters. One manufacturer's stiff is another's regular, and two shafts from the same manufacturer in the same flex can measure thirty cycles apart once they are trimmed and installed.

Measured frequency, installed Roughly corresponds to Typically suits
Under 240 cpm (driver)Ladies / senior territorySpeeds under about 78 mph, or a very smooth transition
240–250 cpmSoft regular78–86 mph with a gradual loading pattern
250–260 cpmRegular to firm regular86–95 mph, the largest band of amateur golfers
260–270 cpmStiff95–103 mph, or lower speed with an abrupt transition
270–280 cpmFirm stiff to soft X103–110 mph
Over 280 cpmX and beyond110 mph and up, or a very aggressive load

These bands are indicative and every one of them has exceptions sitting in our filing cabinet. Transition speed matters at least as much as clubhead speed, which is why the fitting is a measurement and not a lookup.

The properties that matter

Five variables, ranked by how much they change your ball flight

Weight — the one to get right first

Total shaft mass changes tempo, changes where on the face you strike the ball, and changes how the club feels more than any other property. Ten grams is a noticeable difference to most golfers and twenty is dramatic. We test weight bands before anything else and hold the winner fixed while we look at profile.

Frequency — stiffness, measured properly

Cycles per minute on an installed, gripped club with the butt clamped. It captures the whole assembly rather than a raw shaft on a chart, which is why it is the only stiffness figure that appears on our sheets. Every club we build gets a reading, and every set gets checked for a smooth progression from long to short.

Bend profile — where the stiffness sits

Two shafts of identical overall frequency can be stiff in the butt and soft in the tip, or the reverse. Tip-soft profiles raise launch and add spin; tip-firm profiles do the opposite while keeping the club feeling loadable in the hands. This is the property that fine-tunes flight once weight is settled.

Torque — smaller than its reputation

Resistance to twisting, quoted in degrees. It matters most for feel and least for direction, which is the opposite of what most golfers have been told. A low-torque shaft feels firmer and tighter; a high-torque shaft feels smoother. Neither will straighten a miss caused by face angle.

Tip trim — the specification hidden in the build

How much is cut off the narrow end before installation changes the tip stiffness substantially. Two identical shafts trimmed differently are two different clubs. We record the trim on your sheet so that a future rebuild reproduces the club rather than approximating it.

Steel and graphite

Ask about weight, not material

The steel-versus-graphite argument is usually a weight argument wearing a costume. Steel iron shafts run roughly 95 to 130 grams; graphite iron shafts run roughly 55 to 110. The overlap in the middle is large and growing, and in that overlap the material difference is mostly about damping rather than performance.

Graphite genuinely helps golfers with hand or elbow problems, because it absorbs more of the impact shock. It also helps golfers who need to be lighter to maintain speed. Neither of those is a statement about age, and we have fitted plenty of seventy-year-olds into steel and plenty of thirty-year-olds into graphite.

Common mistakes

Four things we see constantly

  • Buying the shaft a tour player uses. Their transition loads a shaft in a way an amateur's does not, and the same shaft behaves like a different club in your hands.
  • Assuming lighter always means faster. Past a certain point, lighter costs strike quality and the net result is shorter.
  • Matching iron shaft weight to driver shaft weight for tidiness. They do different jobs and the numbers rarely want to be close.
  • Ignoring the progression across a set. One soft shaft in the middle of an otherwise consistent ladder ruins a set and is invisible without a frequency reading.

What this page is not

Do not fit yourself from a table

We publish this reference because informed clients ask better questions and because the industry benefits from fewer people believing that a letter on a shaft is a specification. It is not a substitute for putting a frequency analyser on your clubs.

If you want the measurement without the fitting, that is a real service and it costs $12 a club. Bring the set in on a Wednesday, we will read every shaft, write the progression down, and tell you whether anything in it is out of line. Plenty of people do exactly that and buy nothing.

Frequency profile, stock retail set
4-iron268 cpm
5-iron274 cpm
6-iron279 cpm
7-iron281 cpm
8-iron294 cpm
9-iron298 cpm
Pitching wedge304 cpm
A tidy progression until the 7-iron, which sits 13 cycles below where the ladder wants it. That single reading explained a complaint its owner had carried for two seasons.

Book the bench before the season gets away from you

Weekday afternoons open up first. Saturday slots in April and May usually fill about three weeks out, so call earlier than feels necessary.