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Want Some Proof That Well
Designed Driver Faces Beat High MOI for Off-Center Hit Performance?
As we mentioned in the previous article introducing our new
919THI high MOI driver designs, we firmly believe that the most
important factor for achieving the best distance from an off
center hit is the design of the face itself. That’s why
in addition to the higher MOI, the 919THI drivers feature a
superb off-center hit performance from the face design. Since
the proof is in the tasting, shortly after we first published
this statement in a previous E-TECHreport this year, we decided
to embark on some research that we had never seen or heard to
have been performed in the golf equipment industry. We began
to measure the CT of our driver faces in positions ¾”
on the toe and heel, as well as ½” above and below,
the center of the face.
Most Clubmakers are aware of the USGA’s CT test (Characteristic
Time) that is performed to determine whether a clubhead is conforming
under the USGA’s “spring face rule.” What
began in 1998 as a limit for the COR (Coefficient of Restitution)
became a test introduced in 2004 to measure the Characteristic
Time (CT) of the face of clubheads. From 1998 to 2004, the USGA
measured the COR of club faces by launching a ball with an air
cannon to impact the center of the face at a speed of 109mph.
By measuring the rebound speed of the ball off the face, the
COR could be determined. Shortly after the COR rule and test
were implemented, the time required to set up and conduct the
COR measurement began to cause companies to wait as long as
3 months to receive a ruling of the conformity of their submitted
heads from the USGA. In 2002, the USGA began developing a new
test procedure which would determine COR conformity to shorten
the time required to test the head.
In 2004, the USGA announced the implementation of the CT test
to determine the spring face effect of a clubhead. The test
consists of securing the club in the CT test device, initiating
a pendulum to swing from a set distance to contact the center
of the face, and obtaining readings from the sensors in the
end of the pendulum to determine the amount of time in microseconds
(µsec) the pendulum is in contact with the face. The more
“springy” the face, the longer the pendulum is actually
in contact with the face before rebounding free.
Through comparative testing, the USGA determined that a CT
measurement of 257 µsecs was equivalent to a COR of 0.822.
Thus with the CT test in place, the USGA set the spring face
limit for conformity to be a CT measurement of 239 µsecs
(+tolerance of 18 µsecs.) In making the decision for spring
face conformity, the USGA only measures the CT of the face in
the geometric center of the face. Center face CT measurement
is done because it is the position of maximum face flexibility
in all clubheads. Everywhere else on the face is untested because
the USGA is only looking for the maximum spring face effect
of a clubhead to determine its conformity.
While some golf equipment companies may already perform CT
measurements other than the center of the face, TWGT has never
heard of this being done, and we’ve never heard or seen
off center CT measurements published anywhere. We started by
measuring five face positions, center/3/4” toe and heel/1/2”
top and bottom, of our most current driver models, the 949MC,
525GRT and the upcoming 919THI. Heads were selected by testing
for the highest center face CT.
To offer a sense of comparison, we also CT tested a few of
the most popular standard made drivers in the industry for the
same center and off center face positions. For reasons of not
wanting to create any negative or positive publicity, please
respect the fact that we have chosen not to name these four
models we obtained and tested.
While there are variations among all drivers tested, it is
important to realize that being able to keep the COR of a driver
above 0.810 for off center hit locations is quite significant.
For the average golfer with a 90mph swing speed, a difference
in COR between 0.828 and 0.810 would theoretically mean a ball
speed difference of only 1.3mph, which translates to about 2.5
yds. However, it is important to note that even if it were possible
to make the entire face with a 0.830 COR and the head with a
5900 MOI, an off center hit would still generate enough vibration
that some distance would be lost for sure.
The net result of all this is we now understand a little more
about how a good face design can set the stage for less distance
loss. Next we will perform robot hit testing for off center
hit positions to determine real world results in terms of carry
+ roll. So stay tuned.
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TWGT Shaft Fitting Simplified
We know. Shaft fitting can be confusing. Shaft fitting can
be intimidating. Shaft fitting can make you feel you are simply
guessing instead of accurately pinpointing THE shaft for each
player.
By the way, we’re actually working on creating a way
for you to turn the analysis of the golfer’s transition,
tempo and release into a measurement. We’re over one major
hurdle in this task, but we still have a lot of work to do before
this becomes a reality. In the meantime, we want to do the best
we can to help you analyze these shaft specific movements in
the golf swing so your judgments become a little more accurate.
The TRANSITION is the part of the swing when the golfer has
finished the backswing and begins the downswing. Some golfers
start the downswing with a more gradual increase in acceleration
and force. Others begin the downswing with an almost immediate
application of significant force, as if they are trying to accelerate
the club as fast as possible. Still other golfers will start
the downswing with a level of force and acceleration of the
club that is in between these other two examples.
The more sudden, more forceful, and faster the golfer starts
the downswing, the more bending force they will put on the shaft.
As a result, golfers with a STRONG TRANSITION need to be fit
into shafts which are, 1) a little higher in their swing speed
rating than the golfer’s actual clubhead speed, and/or
2) a little more butt stiff in their bend profile design. In
the shaft fitting section presented on pages 50-51 of the 2007
TWGT catalog, we rank a strong transition move with the #3.
Golfers who begin the downswing with a smoother, easier and
more relaxed effort will apply the least amount of bending force
on the shaft. These golfers with a SMOOTH TRANSITION should
be fit into shafts which are, 1) a little lower in their swing
speed rating than the golfer’s actual clubhead speed,
and/or, 2) more butt flexible in their bend profile design.
The smooth transition is rated as a #1 transition move.
And as would be expected, the golfers who start the downswing
with a level of force that is not real forceful yet stronger
than a smooth transition are rated as having a #2 transition
and should be fit into shafts which, 1) have a swing speed rating
for which the golfer’s swing speed falls right in the
middle.
What we call the TEMPO of the swing is a combination of aggressive
quickness in the swing with how the club accelerates to impact
during the downswing. The best way we can explain what we’re
looking for with respect to the effect of swing tempo to shaft
fitting is to ask, how much does the golfer increase, maintain,
or lose the bending action on the shaft during the downswing?
If the golfer is so aggressive on the downswing that they increase
the bending of the shaft, they would be said to have a quick/fast
tempo which we rank as a #3 tempo in our shaft fitting terminology.
On the other hand, a golfer with a #1 or smooth/easy tempo would
give the impression that the club is moving passively, with
little to no acceleration on the downswing. That leaves us with
describing the #2 or average tempo as any golfer who does accelerate
the club on the downswing, but not nearly as much as the golfer
who really gives you the sense they are really accelerating
the club to impact.
Typically, a golfer with a strong transition and a late release
will at least maintain the amount of bending they put on the
shaft as a result of their strong transition and thus be said
to have a #2 average to #3 fast tempo with respect to the effect
on the shaft’s bending amount. While it is possible for
a golfer with a #1 smooth transition to accelerate the club
on the downswing, it is not that likely you’ll see a #1
smooth transition combined with a #3 fast/quick tempo when it
comes to the golfer’s bending action on the shaft during
the downswing.
The third swing movement that has a key effect on shaft fitting
is the unhinging of the wrist-cock angle during the downswing,
or what we call the RELEASE. While proper swing technique calls
for all golfers to hinge the wrists at least 90° at the
end of the backswing and retain that same angle until just before
impact, most golfers simply do not have the strength, flexibility
or athletic ability to do that.
|
Early Release |
Mid Way Release |
Late Release |
You will encounter golfers who release the club
early, midway, or late on the downswing. In our shaft fitting
system, we rate the early release as a #1 release, the midway
as a #2 and the late release as a #3. The release has a bearing
on the proper tip section stiffness design of the bend profile
for the golfer. In short, the later the release, the stiffer
the tip section design should be within the shaft’s bend
profile. Conversely, the earlier the golfer unhinges their wrist-cock
angle after starting the downswing, the more flexible the tip
section design should be. In between would come the mid-way
release with respect to the tip section design of the shaft.
TWGT still has plans to provide video clips of the various
swing moves with respect to shaft fitting. We apologize for
not having done this sooner, but we’ve been pretty busy
with all manner of duties and projects and simply have not been
able to devote the time to completing this task. However, we
do urge all Clubmakers to study pages 50-51 of the 2007 TWGT
catalog to understand how the approach to shaft fitting should
be done. When you feel you have a reasonable understanding of
the description of the #1, 2 and 3 variations of the swing Transition,
Tempo and Release, we recommend you head to a busy driving range
to watch these swing movements on many different golfers to
be able to gain more confidence in making your shaft fitting
swing judgments.
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The Story Behind the Recent
Non-Conformity of Major Brand Drivers by the USGA
If you follow the news of the golf equipment industry, one
of the hottest stories of the spring season has been the USGA’s
discovery of a number of brand name model drivers being sold
at retail that have a CT/COR in violation of the rules of golf,
and the ruling body’s subsequent decision to change the
status of these models to be non-conforming.
The controversy began in April when the USGA was informed that
some of the Nike Sumo2 drivers in retail shops had a COR/CT
that was higher than the 0.830 COR/ 257 CT measurement limit
allowed in the rules of golf. Upon acquiring a number of Sumo2
drivers from retail shops to test, the USGA discovered some
that were over the spring face limit and immediately declared
the Sumo2 to be non-conforming.
A week later, the same situation was discovered about the Callaway
Big Bertha 460, and two weeks after that, models from Cleveland
and Cobra Golf companies were said to also be over the COR/CT
limit and destined to be placed on the USGA’s non-conforming
list.
In all cases, we have heard that each company is re-submitting
new versions of each model to the USGA, each with the required
change in marking on the head, to distinguish them from the
original models now ruled to be non-conforming. The companies
with drivers whose ruling was changed to non-conformity are
all accepting inventory back from retailers to re-test the CT
of the faces, and replacing drivers that prove to be over the
CT limit with ones that are below the rule threshold and which
are marked differently to distinguish from the original versions.
How did this happen and what does this mean to the golf industry
as well as the USGA’s position as the rulemaking body
for the game? A lot of opinions have been flying around since
the matter surfaced, some factual, some simply “a spin
of the story.” Since TWGT has many informed contacts in
the industry and a vast amount of experience in both the politics
and production side of the business, we wanted to share what
we know and what we believe to be fact and fiction in this matter.
It is no doubt the crux of this matter stems from the incredible
pressure on the big golf companies to increase their sales in
the face of intense competition and a gradual softening in the
commerce of the game. Several of our inside contacts stated
that the USGA did not discover these “over the line”
drivers on their own; they were “tipped off” by
one or more of the big golf companies that had embarked on a
program of acquiring samples of their competitors’ drivers
to test and look for competing drivers that were over the USGA’s
limit for spring face effect.
This itself is a pretty nasty commentary on the state of competition
among the big companies. For obvious reasons, the USGA has had
a long standing policy of not accepting equipment for conformity
testing from any entity other than the company or person who
created the model. To do so would open the door to all manner
of potentially dishonest practices by companies against each
other. However, the USGA was alarmed enough by the reports they
received to acquire samples from retail to test and re-visit
their original conforming ruling.
As a result, some insiders are predicting a “witch-hunt”
may be triggered as companies acquire samples of their competitors’
drivers to test and report their findings to the USGA. Since
this matter of previously conforming drivers being made and
sold which are over the CT/COR limit is not isolated to one
company and one model, many are wondering if this represents
a wholesale “thumbing of the nose” by golf companies
to the USGA or isolated accidents in production which caused
a few drivers to be over the limit. Either way, it has the USGA
very worried about how to deal with a situation they have previously
not confronted, and for which they do not have a solution.
Clubmakers are all aware that the limit for the CT/COR in the
USGA Rules of Golf is a CT measurement of 257 µsecs, which
is equivalent to a COR of 0.830. However, the USGA sees the
limit at a CT of 239 µsecs, or a COR of 0.822, with the
allowance of another 18 µsecs in the CT or 0.008 COR points
being the allowed tolerance. Thresholds and tolerances exist
in virtually all USGA rules in which there is a measurement
involved. For example, for the USGA rule limiting the volume/size
of a clubhead, the limit is 460cc with a tolerance of 10cc,
thus making the absolute upper limit 470cc. In the case of the
more recent rule limiting the MOI Izz of drivers to 5900 g-cm2,
there is an additional 100 g-cm2 tolerance which makes the upper
limit 6000 g-cm2.
In all these cases, the USGA does not want companies intentionally
making their equipment to be within the range that includes
the manufacturing tolerance. For example, any company that intentionally
markets and marks a driver head with a volume/size higher than
460cc but not above 470cc will find that driver head ruled non-conforming,
even though technically it is not above the upper limit of 470cc.
The reason is because the USGA wants the tolerance zone for
measurable rule limits to allow for manufacturing “pluses
or minuses” so that no piece of equipment ruled to be
conforming could ever be made, shipped and sold to be over the
limit for the rules which use measurable design parameters as
their defining limit.
Therefore, when it comes to the CT/COR rule, the USGA wants
all companies to make their heads so if every design parameter
were dead-on the design specifications, the driver head would
have a CT/COR of 239/0.822. This way when the foundry makes
heads for each company which would be outside the actual design
specs but within the foundry’s stated +/- tolerances,
all heads would still be below the upper limit in the rules
for the CT/COR of 257/0.830.
The recent discovery of a number of companies’ models
being over the CT/COR limit is not an example of companies trying
to “cheat” and knowingly violate the rule. It is
simply that the companies all want to make their drivers to
be as close to the upper limit for the CT/COR rule as possible.
TWGT has heard comments from Clubmakers and golfers to the effect
of why don’t all the companies test every driver for CT/COR
that they produce and sell. While a noble thought, it is simply
not humanly possible to do that within each company’s
budget and customer service parameters. At best, a reliably
accurate CT test cannot be performed in less than 15 minutes.
If a company makes and sells 250,000 or more drivers per year,
a number that applies to several of the big golf club companies
today, performing a CT test on every one would require 32 people
working 8 hours a day, Monday to Friday for 52 weeks a year
to complete the task! What are already expensive golf clubs
would become even more so, with delays in delivery to retailers
being an additional result.
What is the USGA going to do about this? One of TWGT’s
inside sources revealed that the USGA knows they cannot embark
on a program to constantly spot-test all companies’ drivers
after a conforming ruling has been issued. There are simply
too many companies and too many driver models being made and
sold in the industry today to allow the USGA to initiate such
a program. At the same time, the USGA does not wish to ignore
the problem.
While there may be other options as yet undiscovered, many
industry experts are saying this will signal the start of the
USGA beginning to seriously consider separate rules for equipment
for elite player competition vs. regular golfers. Bifurcation
is the fancy word being used to describe the possibility that
the USGA may break with tradition and begin to consider setting
up separate equipment rules.
While no one yet knows what the outcome of this controversy
will be, it is certain that something will be proposed by the
USGA in an effort to keep some form of control over the game’s
equipment. What this will be, and whether it too may end up
being subrogated by the companies remains to be seen. As we
have said before in ongoing situations related to clubmaking,
stay tuned because we have not heard the end of this by all
means.
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What Else is New from TWGT?
In addition to the new 919THI high MOI drivers, TWGT has been
busy and is pleased to announce a number of new items for your
clubmaking and clubfitting.
1. 525F/D Fairway Driver
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Announced in last month’s E-TECHreport,
the 13°/ 208 gram model 525F/D fairway driver will be
here very soon to offer golfers an alternative for distance
with control on tight tee shots. Approved by the USGA as
conforming to the rules of golf, we think
Clubmakers and golfers are going to be very pleased with
the performance the 525F/D can
offer to golfers. Remember – the 525F/D is a niche
specialty design created primarily for use off the tee
on par-4 and par-5 holes which place a definite premium
on accuracy with good distance. With a 200cc head volume
and 40mm face height, the 525F/D is going to be a club
to hit “off the deck” for long second shots
only for very skilled players. Primarily, it is a tee
shot club intended to be built to 42.5”-43.5”
to offer control, accuracy and high ball speed but with
13° loft and a well designed forged cup-face for superb
off center hit performance as well. Available in mid June. |
| 2. New Single Bend Steel Putter Shaft Designed for
use in any putter head with a 90° bore angle, TWGT
is offering a new single bend steel putter shaft for golfers
who do not wish to have the shaft create any offset in
the set up of the putter. The 0.370” tip single
bend shaft delivers a standard lie angle of 72°, but
can be bent for lie changes with a putter shaft bending
tool. Can also be used for left hand putter heads with
a bore angle of 90°. Raw length 36”.
Order code 51SB90 |
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| 3. New Dark Brown TacTrac Men’s
Grips |
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One of the most exciting products from
TWGT in 2007 are the new TacTrac urethane grips. Manufactured
through a unique process which applies the urethane grip
material on the underlisting without a seam, we’ve
received hundreds of reports from Clubmakers that their
golfers like the TacTrac grips because they wear longer
than other urethane grips and have just the right amount
of tackiness in their feel.
For mid-season, we’ve added on a brand new dark
brown TacTrac in both Men’s Standard and Men’s
1/32” oversize to join the existing black men’s
and burgundy ladies models. Available in early July.
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| 4. New Oversize Black TacTrac Putter Grip |
|
For golfers who prefer a putter grip with
a wider front and a larger overall size, we’ve added
a new oversize TacTrac putter grip in black to join the
existing conventional size TacTrac putter grip. Available
in early July.
|
5. New 915F/H Fairway Hybrid in 25° Loft
One of the most versatile and best new performers in the
TWGT original clubhead design line are the 915F/H fairway
hybrids. The 915F/H represents a design which has normal
face progression like a typical fairway wood, but in a
smaller face to back size with two weight bores so the
models can be built as a fairway wood or a shorter length
hybrid long iron replacement.
Key to the versatility of the 915F/H are the TWO WEIGHT
BORES designed into each head. With one weight bore in
the typical position at the base of the shaft bore and
the other on the toe side of the sole, Clubmakers can
build each 915F/H head to a 3”+ range in playing
length.
The new 915F/H - 25° addition can be built to be
a 9-wood (39.5-40.5”) or a 4-hybrid (38.5-39”)
iron replacement, or in between as desired by the player.
Available in mid June. |
 |
 |
6. New CX Micro 58° Wedge with 8° Bounce
Already in stock and shipping, the new 58°/8°
CX Micro wedge offers golfers a lower bounce sole angle
alternative in a sand or lob wedge loft.
a. Ideal for players who keep the sand wedge more shallow
through the sand
b. Good for normal sand play from bunkers with heavier,
more coarse sand
c. Offers a great wedge for use from tall grass around
the green
d. An ideal combination wedge for golfers who do not want
to carry separate sand and lob wedges in the bag
e. Available now in both satin nickel chrome and dark
nickel platinum plated finishes – 298g headweight,
64° lie.
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Search Driver Becomes Second
TWGT Book to Win ING Award
Last
year, the International Network of Golf selected “The
Search for the Perfect Golf Club” as the organization’s
Book of the Year for 2006. In a recently issued press release,
the industry’s largest organization of golf media professionals
has announced that Tom Wishon’s follow up book, “The
Search for the Perfect Driver”, has been selected for
one of the ING’s prestigious awards for 2007. Whether
Search Driver follows the lead of Search Club to win the Book
of the Year for 2007 or a different ING distinction will be
revealed at the ING’s annual spring conference on June
3 at the Turning Stone Resort in Vernon, New York.
TWGT is very pleased and grateful that the golf industry’s
largest and oldest organization of writers and media professionals
has selected Tom’s latest and second book for regular
golfers to be so honored.
When asked to comment, Tom Wishon said, “I truly believe
the ING’s recognition of Search Driver on the heels
of choosing Search Club as their Book of the Year in 2006
is a statement that the industry’s golf media truly
believes all golfers need the information in the Search books.
Since Search Club was released in the spring of 2005, only
two of the golf industry’s numerous golf magazines have
previewed and shown either one of the Search books in their
pages for fear of the truthful information contained in the
books causing their OEM advertisers to complain. It really
is nice to know that the golf writers and media professionals
think enough of this information on their own to band together
through the ING to give the books this stamp of approval.”
Hundreds of custom Clubmakers have seen a real increase in
the number of custom clubs they fit and build for golfers
because of the message in the Search books and 12 Myths booklet.
If you are a clubmaker who desires more business, that goal
is only as far away as your effort to give away 12 Myths booklets
or loan a copy of one of the Search books to as many golfers
in your area as you can find. If you are a clubmaker who is
not interested in increasing your clubmaking work, for the
good of your fellow Clubmakers who do, we urge you to tell
all the golfers you see to read this information.
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Within
the past month, Clubmakers who use TWGT’s Series
5 Steel wood and iron shafts in their fitting and clubmaking
may have noticed a little change in our popular, solid
performing lightweight steel shafts. Previously made to
TWGT’s specs by Royal Precision, the Series 5 steel
shafts are now being manufactured by True Temper.
