Effects of Shaft Features
- There's a whole separate chapter on this; check it out!
- Kick point, bend
point, flex point
The "kick point", "bend point", or "flex point" of a
shaft, is a measure of whether the bending tendency is higher or lower
on the shaft. They are not merely different names; there are at least
two ways of measuring them, one usually attributed to kick point and
the other to bend point.
These points are said to affect:
Shafts with a high kick point feel more "one piece" than shafts
with low kick points, at least for golfers sensitive enough to
feel the difference.
Shafts with a low kick point are more "tip-flexible"
and feel that way.
The position of the kick point makes a difference in the trajectory
of the ball, though not a large one.
In general, the lower the kick point, the higher the trajectory.
There is still much debate whether this is even true,
so let me conclude this section with a discussion of the
pros and cons of affecting trajectory with kick point.
This was considered a very interesting parameter until the
early 2000s. It is a lot less so today. In the first place, actual
measurement shows a very small range for the kick point (or, for that
matter, bend point) range. It varies only an inch or two over the
collection of shafts measured, in the studies I am familiar with. So it
really isn't a very good measure of trajectory. Russ Ryden's work
on EI profiles is starting to tell us a lot more about what
to look for in a shaft -- and it involves the whole shaft's flex
profile, not just a single, easily measured number to represent the
- There's a whole separate chapter on this; check it out!
During the 1920s and '30s, shafts evolved from wood
(mostly hickory) to steel. They probably picked up a little weight in
the process, but the results were much more repeatable and predictable,
and the torsional rigidity of steel was much greater. Steel remains the
predominant shaft today, but that was challenged in the '80s and '90s
by composites of strong fibers laminated in epoxy resin. The most
common of these fibers for golf clubs is carbon (usually but
incorrectly referredto as "graphite"), though boron, kevlar, and glass
fibers are also on the market. The "exotic" fibers are usually an
additive to a mostly-graphite shaft.
Until the mid-'90s, composite shafts were a distinct
throwback to the beginning of the twentieth century. The graphite
shafts were lighter, but less reproducible and given to low torsional
rigidity. Recently, graphite shafts have tighter specs on everything,
and torsion characteristics may even be comparable to steel; but that
comes at a price in dollars and/or weight. However, there are
in-between shafts -- not challenging specs and tight
tolerances perhaps, but reasonable specs and tolerances -- that are
It's worth listing some of the special characteristics of
composite shafts, so the club designer can decide when they're useful
and when they're simply a mark of conspicuous consumption:
- It was possible to generalize about shaft price when
this was first written in 1998. There is a lot more variety in the
market today (2017). Prices are being pushed up -- sometimes way up --
by selling some shafts as "boutique" or high-performance shafts. At the
same time, manufacturers have learned to build reasonable quality into
graphite shafts, so there are competent consumer-grade shafts for
rather reasonable prices. So the only generalizations I'm willing to
make about price is that there is a huge range of prices for both steel
and graphte (more for graphite), and considerable overlap of prices
between graphite and steel. Here are a few points for comparison.
Prices are approximate, and depend on where you buy them.
- TrueTemper Dynalite and TT Lite: $10-$15.
- TrueTemper Dynamic Gold: $20-$30.
- KBS S-Taper: $55.
- Component house brands: $10-$25.
- Name brand general market shafts: $30-$80.
- Premium and "boutique" shafts: up to $300 and
Before we leave the subject of graphite shafts, it's worth mentioning
a few myths about them, and explaining the reality: A lot of people
assume that graphite shafts have more "whip"
(whatever that means)
than steel shafts.
This assumption leads to an assumption that graphite-shafted clubs
will hit further than steel.
- I've collected enough informal data (no, not a
controlled experiment, but anecdotal) to convince me that steel shafts
are more durable than graphite over the first 10-15 years of life.
There isn't much data on graphite for longer periods, so we don't know
any of its long-term failure mechanisms. Steel rusts over time, but
seldom fails due to rust in the first 10-15 years unless
left exposed to the elements..
Graphite is simply weaker than steel when subjected
to concentrated shock.
- Graphite, but not steel, shafts have failed,
especially in short-hosel drivers. (This has been ameliorated in some
models of graphite shaft by beefing up the tip. But that has reduced
graphite's advantage in keeping swingweight down.)
- Graphite, but not steel, shafts require coning (and sometimes
ferrules) to ward off premature failure in any installation.
- Where light weight is desirable in a shaft, graphite
can supply it. The lightest graphite shafts are less than half the
weight of the heaviest steel shafts. Remember that a saving of about
six grams of shaft weight is a reduction of one swingweight point. Thus
moving from a "typical" steel shaft (at 120g) to a "typical" graphite
shaft (at 70g) will save 8 swingweight points. This is worth more than
an inch of extra length (close to an inch and a half) for the same
The way to use graphite's lower weight for improved
performance is to either:
Both of these assume you can control the resulting club, which may or
may not be a good assumption. If you can handle the extra length, or if
you can handle the reduced inertial resistance, then the result will be
- Use it to make a longer club at the same
swingweight or MOI.
- Use it to make a club with a lower swingweight or
But the biggest advantage of reduced weight,
especially in clubs other than a driver, is not the performance for any
single shot. Rather, it is the golfer's own improved performance due to
not being as fatigued late in the round. Carrying or pushing a heavy
bag, or even just swinging heavy clubs, can hurt a golfer's ability to
perform late on the back nine.
- Vibration damping:
- Graphite shafts cut the high-frequency vibrations of
the impact between clubhead and ball, whereas steel transmits them to
the hands. Thus graphites feel less harsh. This may be an expensive
for some golfers, but can be a necessity if:
- You have a medical condition that is aggravated by
shock, such as arthritis in the hands or arms.
- You hit 300 practice balls a day, as the pros do.
It is conventional wisdom among golfers that the vibration-damping of
graphite prevents or alleviates shock-related or repetitive-motion
injuries. I have seen no medical study to confirm this, so I can't
endorse that position. But there is certainly plenty of anecdotal data
to support it.
- Arbitrary design characteristics:
- The fabrication process for composite shafts allows
the possibility of building in characteristics that you couldn't in
steel (at least not without some costly fabrication problems). As a
result, we have a few examples of shafts with novel specs:
- The "Nitro Flex", a very whippy shaft that still
has good torsional resistance.
- A variety of "tip-heavy" shafts, for those who
want the vibration damping of graphite, but don't want the weight
- A few extremely whippy shafts (more flexible and
lighter than can be made reliably in steel) for very slow swingers. A
prime example is the FiberSpeed shaft, a composite shaft where the
fiber is glass, not graphite.
- When this chapter was written in 1998, this
advantage of graphite was more theoretical
than real; there weren't many shafts out there whose desirable
characteristics (except for weight and vibration damping) couldn't be
duplicated in steel. But in 2017, shaft designers are using composites
to tailor the bend profile, torque, and even resistance to ovaling
(incorrectly referred to as "hoop strength" in the shaft industry), in
ways that would be impossible in steel.
The first assumption (more whip) is simply not true.
Graphite shafts tend to cover a similar range of flexes as
steel shafts of the same nominal flex grade.
Admittedly, it is possible to build graphite shafts
softer or stiffer
But this is only an issue if you need
something stiffer than a Rifle FCM 7.5,
or something softer than a True Temper Release "L".
There aren't many golfers whose proper shaft is outside these extremes.
For the rest of the world, there's nothing magic about the flex of
- The second (more distance), where it is true at all,
is a consequence of the lower weight of graphite,
seldom its flex characteristics.
- When discussing shafts, "torque" refers to the ability of
shaft to resist a twisting force about its centerline.
Actually, the technical term "torque" really refers to the twisting
as we saw in the section on physical principles.
The proper measurement of torque would be to measure the twisting
moment, in some unit like foot-pounds or gram-inches.
But for shafts, the measurement is degrees of twist for a given
A high torque rating paradoxically means that the club is low
twist. It really isn't high in torque; quite the opposite, it is high
in "torsional deflection".
I said a "given" applied torqe, not "standard". There is
in fact a standard torque for this measurement: one foot-pound. But the
test really isn't quite standard because the clamps at each end
(applying the foot-pound of torque) and the unclamped length to be
measured are not standardized.
Torque can be, and often is, significantly different for
Steel shafts are pretty stiff in resisting torque,
and there is little to choose among them.
The typical steel shaft will have 2.5-3.0 degrees of torque
for "wood" shafts and 1.7-2.0 degrees for "iron" shafts.
- Graphite shafts are naturally flexy in torsion.
Low-priced graphite shafts are generally over 4 degrees,
and as high as 7 degrees.
In order to compete with steel in twisting rigidity,
the manufacturer must do something special.
That usually results in a substantial increase in weight
(sometimes to the point of similarity with steel)
or a substantial increase in price. Typically, the fix is some of each:
weight and price. Layers of carbon fiber are added to the shaft, with
the fibers oriented on a 45° bias; that direction provides maximum
resistance to torque. The extra layers add weight and cost.
Under the dynamic forces of the swing, the clubhead will twist through
the ball, just as the shaft whips through the ball in flex.
This means that there is a second dimension to worry whether it's at
the proper point in the load-unload cycle when the clubhead meets the
There are several schools of dealing with this, to whit:
Consider torsional flexibility to be a degradation to
This is my preferred approach.
I would buy the shaft with the right flex and the stiffest torque
I could afford.
(Of course, this isn't an issue with steel.
But if you need graphite, it becomes a serious economic consideration.)
This solution comes with a price. Reducing torsion
turns out to make the shaft feel a lot stiffer, even if the actual flex
is not affected. Which brings us to...
- Trade off torsional stiffness against shaft
to give an overall "feel".
For instance, consider two shafts "A" and "B".
"A" is "looser" in torque than "B", but is enough stiffer in
flex that it matches the same golfer.
What is the "currency" of the trade?
According to Summitt
frequency (a measure of shaft flex) trades against the fifth root of
For example, a 5% increase in torque can be countered by making the
stiffer to the tune of a 1% increase in frequency.
Unfortunately, the relationship doesn't stay linear over a very wide
range. For instance, many budget and mid-priced graphite shafts have
a torque twice that of a comparable steel shaft.
Using the fifth-root trade, a steel shaft would have to be 15% softer
(measured in frequency) than the graphite shaft. A 15% frequency
difference corresponds to the difference between an X-flex and an
L-flex for shafts rated on the FCM scale.
I report this approach because it is the conclusion of
the authors of
a widely-respected study of shafts.
However, I have a lot of trouble buying it.
I can believe that the tradeoff could result in a constant
but doubt that it would provide constant
The essence of flex matching is to unload the shaft at the right point
in the golfer's swing.
- If "torque matching" has any validity at all,
its essence should be, similarly, to unload the
rotational energy in the shaft at the right point in the swing.
- But the notion of a trade denies these essences;
it trades degree of unloading in one axis for unloading in another.
Using the trade, the direction of the clubface at impact would be
dependent on where you were on the trade curve.
That's not what shaft matching is about.
Find the ideal torque for the golfer's swing,
so the head is exactly square at impact.
This is analogous to choosing the flex,
and is arguably the only correct way to do it.
However, nobody does it this way, and it's safe to say that
nobody really knows how to do it systematically.
My conclusion about torque? If money is no object, go ahead; make
Aldila's day and get low-torsion graphite. But be aware that most
inexpensive graphite shafts are not low-torsion.
If money is a consideration, here's my personal strategy:
- For the driver, decide what length and swingweight you
want. If the result calls for a lighter weight shaft than steel can
provide (and it almost certainly will), get graphite in the torsional
stiffness your swing needs.
- For the irons, it is more likely that steel will be
the preferred material; many stronger golfers actually need the extra
weight to regulate their swings. But there will still be plenty of
golfers who want the lighter weight or vibration damping of graphite.
For them, either pay for tighter torque or determine what they really
need. It may be OK with garden-variety graphite, since an iron head has
much less moment of inertia than a driver head, and thus requires less
torque to square it up.
- As with torsion, you pay for low weight. You may pay for
it in dollars, or it may be in torque. As the weight decreases, the
hardest spec to maintain is torque. So you may have to strike a happy
medium in specs or dollars. My strategy here is the same as
with torsion; for the
majority of your clubs,
For a driver, especially an over-length one, do what you
need to do.
Last modified May 15,