Driver Head Weight and Club Length
Dave Tutelman -- October 28, 2012
Evidence, Anecdotal and Otherwise
We have a problem here! Some studies don't agree with others, nor with some reality-check data that we have. Why not? Here
are a few possible explanations I can come up with. The evidence is
common-sense but mostly anecdotal.
Let's start with the fact that the model showed lighter clubheads
superior at less than 150 grams, for variable length with constant
MOI. But most real-world experience does not bear this out. Few
clubmakers report success with clubheads under 190 grams. Why should
really light clubheads may
be difficult. I am used to seeing quotes like the
Bernie Baymiller (a good golfer and clubfitter, mostly for seniors)
posted in Shoptalk, May 4, 2011
... most of the guys for whom I build long drivers,
seem to prefer and
do better with the 190 than the 175 when they demo them side by side.
Again Bernie Baymiller, June 3, 2011
... I'm using a UL-45 R on a 10.5° BOM right now at
47" club length
and getting good results. A DTG 190 9°on an SKF PE A also produced good
results with a slightly lower trajectory. I don't like the 175 gram
heads much, though. They don't have as much "pop" for me as the DTG
190. For me, at a 47" club length, I still think a 190-195 gram head
on a low 50s gram shaft delivers the best distance. My BOM weighs 193
David Dugally (a component designer and clubfitter) posted in Shoptalk,
May 3, 2011
- UL-45 R is an ultra-light shaft weighing between 45 and 50 grams, in an R-flex. It is made by Diamond Tour Golf.
- BOM is a Bang-O-Matic head, weighing about 195 grams, made by Bang Golf.
- DTG 190 is Diamond Tour Golf's lightweight head (190 grams).
- SKF PE is a lightweight shaft called the Pure Energy, made by SK Fiber.
There is a trade off between speed and mass, the
lighter head increases
speed, but reduces mass.
This is counter to the computer studies, which show that long drivers
continue to hit the ball significantly farther as the weight decreases.
Perhaps the answer is contained in this post to Spinetalk by Danny
Seng (a clubfitter from Australia), October 26, 2012:
In working with arguably the Jack Nicklaus of long drive Gerry James,
we worked with heads from about 179 grams to about 207 grams and got
the best Ball Speed with a head at 193 grams, now his swing speed at
the time was about 138 mph, I do not know how this would fall off or
increase as swing speed decreases, but it seems to be consistent with
your results so maybe it doesn't fall off with swing speed, maybe
that's the ticket.
Perhaps Dave T knows the math, I don't, I only know the results.
There are heaps of Titanium driver heads these days
and especially the
lighter 175g heads tends to generate less mass and as a result the lack
of distance is always the complain.
This suggests that not every club manufacturer can build a fully
capable driver head at 175 grams. In order to get a high COR and
maintain it across the whole face, you need to provide adequate support
in the clubhead surrounding the face. If there is not enough rigidity
there, a lot of the spring face's effectiveness is lost.
Japanese driver heads does comes in the same 175 to 180 gm weights but
they are far more superior and the results are there.
Driver heads in the 175 and 180gm that I have huge success are from
John Muir products I have yet to come across one that really deliver
the distance desired.
In the 190 gm weight the greatest success are from David's Vector
series and Tom Wishon. The rest are mediocre at best.
Danny talks about much better heads from Japan at really light weight
(175-180 grams) than he sees elsewhere. And he attributes this (in
other posts) to the fact that the Japanese adopted longer, lighter
drivers much earlier than the US; he cited the 1980s. So they have much
more experience with very light clubheads for long drivers.
This may explain why long drivers with
heads under about 190g do not continue to improve distance. But Bernie,
David, and Danny all have positive things to say about long drivers
with head weights around 190g.
people can make it work, and some can't. Danny Seng explicitly
acknowledges that not everyone
can or should play a longer, lighter driver. It is harder to control,
and costs accuracy. From private email from Danny Seng on
November 11, 2012:
- Bernie says they give him 25-30 extra yards. He also cites a
senior lady who got an extra 35 yards.
(To repeat, the model predicts
around 10 yards -- worthwhile, but nowhere near this.)
- David cited his work with Gerry James, a well-known long-drive
champion. They did extensive testing, and determined that Gerry got his
best ball speed with a 193g clubhead and a 48"+ club length.
- Danny believes there is a tradeoff between accuracy and distance
when going to longer, lighter clubs (which I confirmed when I began
experimenting; see below). But he feels that there is a real advantage
for smaller or less strong players who can learn to swing a longer
driver. Which brings us to...
There is no question that a shorter length club
generates greater accuracy. KZG article derive driving accuracy data
from Pros. I do not dispute that either, nor have any objections on
other write ups you have pointed on this topic. Working in Asia and
Australia we have the best of both worlds to experience. In Asia for
years we have Asian golfer with drivers at 48 " longer under the 300 g
mark for total weight, and they drive awesome distance. We use to
marvel at that. But in that same breath we have Asian customers build
like amazon unable to use these type of specifications, and needs to
reshaft their drivers.
Also from Danny, November 28, 2012, after relating an experience with
Euan Walters, a winner on the Australian PGA tour:
There is a statement to be made here. In the hands
of a professional the longer, lighter weighted driver generates greater
So it takes skill and consistency to make a longer driver work. There is formal research confirming
that enough skill and consistency can make it work. Bernie Baymiller
has pointed out to me a scientific paper from the journal Sports Biomechanics, "Influence
of shaft length on golf driving performance"
by Ian C. Kenney, Eric S. Wallace, and Steve R. Otto of the University
of Limerick. They tested seven Category 1 golfers (handicap index less
than 5), most in their early twenties, using drivers of length 46",
48", and 50". Here are some of the results that I think are important:
Again, remember that the test subjects are elite golfers. Many
clubfitters feel that a long driver is a mistake for most golfers.
Tom Wishon has been the most vocal proponent of
this position, and I have supported it for years. From Tom's web page on driver fitting:
- There was some gain of distance going from 46" to 48". The
average gain was 6.3 yards. If we assume that same rate of gain over
the whole 45" to 48", that is 9.9 yards, very close to the 10 yards that our
computer model predicted.
- When you think about it, the gain is even less than what the
computer model predicted. The computer model was based on a 100mph
clubhead speed. The golfers in this study were young, near-scratch
golfers. I have to believe they had clubhead speeds between 110 and
120mph. So they might expect an additional yard or two, compared with
the computer model.
- There was no further distance increase in going to a 50" driver.
Well, at least not on average. Some could make it work, and others did
worse with it.
- One of the test subjects got considerably more distance gain:
about 23 yards going from 46" to 50". This is outlier data, but still it is actual, measured fact.
- Most surprising to me was that there was no falloff of
directional accuracy as they went to longer drivers.
It’s time to be blunt. The standard driver
length of 45.5 to 46.5
inches offered by the majority of golf club companies is too long for
the majority of golfers and will prevent at least 75% of all golfers
from achieving their maximum potential for distance and accuracy.
For men with an average to fast tempo with an outside/in swing path,
44” should be the maximum length; women, 42.5” to 43” should be the
limit. There’s a very good reason the average driver length on
the US PGA Tour since 2005 has been 44.5” and not 45.5” to 46.5”.
Tom has a great anecdote about the difficulty of hitting a
long driver in his booklet, "The
Search for the Perfect Golf Club".
How can we account for the sort of distance changes that Baymiller
reports, Seng implies, and Kenney's research finds as an outlier? In
the first place, it can only be accounted
for by a different swing, a difference that favors the longer driver.
Something had to happen to increase the distance so much more than the
10 yards that physics gives it. A few possibilties:
Bear in mind that these other factors must also account for the need
for repeatable accuracy that Wishon cites and I certainly experienced
- The particular golfer is just better suited to the longer driver.
Perhaps their swing benefits considerably from a flatter plane, or
perhaps the increase in swingweight regulates their swing better. (The computer
model kept the same MOI, but Baymiller's experiences are all with a
considerable increase in MOI going to the longer driver.) Perhaps there
was a shaft with a very different flex profile, better suited to the
- The particular golfer was doing something very wrong with their
shorter driver. In other words, the large gain comes from the fact that
their old driver was not a hard act to follow.
- The measurement and reporting of the gain is flawed. (Read on,
and you will find out how easy it is for this to happen. I did it
myself for my first cut.)
How do you keep
In the game of golf, score is kept by strokes. But not everybody plays
golf to minimize their total strokes. As the club manufacturers well
know, many (probably most) of their customers want to remember a really
long drive or two from each round, or they want to out-drive their
buddies. If they have that, a high stroke count will not bother them.
If you don't believe this phenomenon, compare PGA Tour statistics with
commercial sales of golf clubs. In 2005, the average driver length on
the Tour was 44.5". Depending on whom you listen to,
it may still be there, or it may have crept up close to 45". But no
higher than that. In any event, it is nowhere near the 48" allowed by
the Rules of Golf. Yet off-the-rack drivers from the major
manufacturers are in the 45.5" to 46.5" range. It would appear they are
selling to people who don't keep score by strokes. Think about it; the
Tour players collectively have as much skill and consistency as any
golfers on the planet, and they are not using 48" drivers.
is a golf sport where score is kept by driving distance!
The LDA (Long Drivers of America) have a competition circuit and even a
world championship (the ReMax Long Drive Championship) based on how far
you can hit the ball. Moreover, consistency does not win; you get six tries,
and only your longest drive (in a very wide "fairway") counts. Not
surprisingly, those guys use
the longest shafts they are allowed to.
They have the skill to find the sweet spot, and get six chances to find
it once -- so they can afford to trade consistency for any increase in distance.
Let's see what a few of them have to say:
-- I met Jeff through David Dugally in 2011, and David suggested I
contact him again for this study. He was very forthcoming about his
club choices, and had an interesting and perceptive take on it.
Many LDA guys now believe that a little heavier head is the way to go
if you lose the speed in your swing. Many reports have David
Mobley using a 210 gram head thus giving him more mass behind the ball
which makes up for some of the speed he may have lost in the aging
I agree with Jeff that clubhead speed is more important than "mass
behind the ball". In fact, that is what this whole article is about,
the tradeoff between clubhead speed and clubhead mass. We were talking
about a constant length here; the LDA competitors all use maximum
Mobley (according to Farley; remember,
this is "many reports", not definitive fact) may have something. The
ball speed does not change much for tens of grams around 200g, so a
big, strong guy might well make a better swing with a heavier club. A
"better swing" might mean higher clubhead speed, more consistent sweet
spot contact, or both. Every clubfitter knows that the club's heft must
be fitted to the golfer; too light or too heavy, and the swing
degenerates to some extent. Apparently, Mobley is best fit to a heavier
Here are my thoughts. I still believe that I must use a head
around 194 grams. I would go lighter if I could still find a way
to feel the club head at the bottom. The way to hit the ball
further is to create speed which is why you see skinny non muscular
guys who can pound it.
Jeff is right that, unless you actually need the weight to regulate the
quality of your swing, you'll hit the ball farther with a lighter head.
The "skinny non muscular guys" are a better fit to less heft than
Then Jeff makes an even more interesting statement.
One can do different
exercises to hit the ball further but increasing the driver length will
give you instant distance if you can continue to hit the sweet spot and
maintain good golf fundamentals. I use a 48 inch driver in LDA
competition and a 45 inch driver for golf. I call this my playing
driver because I can control it better when I am swinging well.
The 45 incher limits the errant shots. There is about a 15-25
yard difference between my playing driver and my long driver.
There are a few very telling points here:
When I long drive I like a 6 degree
loft. When playing golf with the shorter driver I like the loft a good
1.5 degree higher which I believe gives me more accuracy. A key thing
here is that I am covering the ball more when playing golf, unlike when
long driving -- in long drive I am trying to release the club as hard as
possible making me very handsy.
- He himself uses a 45" driver to play golf and a 48" driver for long-drive competitions. 'Nuff said!
- He knows he uses a different swing for long drive competition
than he does for just playing golf. So the 15-25 yard difference is
only partially explained by the club's dimensions. The rest is in the different
- "...Increasing the driver length will give you instant distance
if you can continue to hit the sweet spot..." Remember this when you
see my own test results below. I found the converse also to be true: If
you can't hit the sweet spot with the longer driver, you will not get
When Rick Malm saw my article, he suggested I get in touch with
Tyler Kellett, as Tyler had worked very closely with the experts from
Krank in tuning his LDA competition drivers and understands what they
do. When I talked to Tyler, one of the most important themes that came
through is how different long drive competition is from golf -- and how
that colors all the equipment selection decisions. I'd like to do a
separate article on that sometime, but here are the things that we
talked about having to do with head weight and club length -- the topic
of this article.
- A 1% increase in clubhead speed for your regular golfer is about
1mph, which can give an additional 3 yards. That will not make a
difference in score over the course of a round. On the other hand, a 1%
increase in clubhead speed for a long drive competitor is about
1-1/3mph, which is worth 4 yards. Not that much more, but in long drive competition
it is often "the difference between moving on to the next stage and going home" (Tyler's words). Long drive is about eking every yard out of your drive that you can!
- Almost every LDA competitor uses a maximum-length driver, and
even those who don't will use something pretty close -- certainly a lot
longer than commercial drivers or those used on the PGA Tour.
- Tyler found his own ideal clubhead weight by careful and
exhaustive testing. He tested using a maximum-length driver with his correct
shaft and a TaylorMade R7 head (which is not
the head he uses in competition). Why that head? He was able to use the
weight screws to change the head weight over quite a large range; he
used some custom tungsten weight screws to get the range up. Note that he was not trying to shape the trajectory with the screws, just vary the head weight until he got maximum ball speed.
- The weight he found from this exercise is definitely not the
lightest possible -- not even under 200g. He pointed out that some LDA
guys are very strong and others are very quick. The strong ones get
better ball speed from heavier heads (as heavy as 210g, and even more),
and the quick ones from lighter heads (in the low 190s).
- An LDA competition involves a
bunch of matches in a day. For instance, the world championships are 14
rounds in two days. That presents a problem with a higher
weight; you get more tired more quickly the heavier the driver you use.
If your optimum head weight when you're fresh is a heavy head, it may
tire you out in a tournament. Tyler says you might do well to go 5-10g
less than that.
- The latest generation of LDA drivers have the placement of the weight designed as carefully as the amount
of weight. I was surprised at the trend. Tyler told me that we have
gone a little overboard in reducing spin; we have gotten very good at
it, perhaps too good for long drive. (This does not question that
higher launch and lower spin are a winning formula for stronger amateur and professional
golfers, in the 100-120mph range. But this is not the same as long drive competitors.) So long drive clubs are now going to
a center of gravity that is higher and closer to the face, which gives
more backspin. If you understood my article on vertical gear effect,
you know exactly why these changes will remove gear effect topspin. (I
have not done any studies to verify which ball speeds benefit from more
backspin and which from less. Sounds like an interesting project for
people in golf have a higher estimation than I do of how
much increased clubhead mass will turn into ball speed through momentum
transfer. Tyler is no exception. He disagreed when I said how much
(actually how little) a given change in clubhead mass affects ball
speed --that a 5% change in driver head mass gives only a 1% change in
ball speed. But I stand by it. It goes back to a very basic piece of
physics, the equation for ball speed
based on momentum and energy transfer. The equation appears in Cochran
& Stobbs' classic 1968 book, and in a huge number of research
papers in golf engineering. You can set up the equations with stuff
from college Physics 101 (first-term freshman physics), though solving
the equations may require some tricky algebra. I have no doubt the
results of the equation are correct.
My Own Experience
Oftimes, analysis is enlighted by personal experience. By now, I was
beginning to feel this was one of those times. So, with a little advice
from Bernie Baymiller, I went ahead and built myself a long driver. The
components were from Diamond Tour Golf, and Bernie said he had used
them successfully more than once. I used their house brand 190g head
(12º loft, like my usual driver) and their house brand 48g shaft. The
result was 47.5"
long, just on the verge of legality. (For reference purposes, it is
exactly 3" longer than my usual driver.)
I then set about to gain some insight through experience. I started
with a range session, and quickly convinced myself that I didn't need a
lot of work learning a new swing. Just keep it smooth, swing by
rotating the body, and keep a light grip -- don't make the release
happen, but allow
to happen on its own. Those are the same swing keys I find
productive with any swing, especially a driver swing. But it seemed to
be more important for the longer driver. (Note that this is just the
opposite of Bernie Baymiller's advice. I did nothing to advance the
release earlier in the downswing, and got bad results when I tried.)
My next round, I didn't go straight to the long driver. Instead, I
practiced those same swing keys with my usual driver, in part to
establish a benchmark for comparison. (It was a good benchmark; by the
back nine, my game was as sharp as it has been all year. I set a
personal best for that back nine, and got my first back-to-back birdies
in years. One conclusion: even if the long driver doesn't work for me
on the course, it seems very effective as a training driver.)
For the following several weeks, perhaps ten rounds, I used the long
driver exclusively. I also did some "lab tests" indoors with a launch
course: averages, apples, and oranges.
From the first, I noticed that my best drives were 15-25 yards longer
than I was used to at those courses. Maybe there is something to this
Then I realized something. If the point is to compare
wrong way to do it is to compare your best drives with one driver
against the typical drive with your other driver. You must not
compare apples and oranges. (After realizing this, I began to wonder if
that is how the 'testimonials' for longer drivers get the large gains
that they do.)
So let's compare best drives with best drives, average drives with
average drives, etc. This table is my summary of those impressions.
Again, these are impressions, not controlled measurements. The best I
can say in their defense is that they were recorded at courses that I
play all the time, and playing with my usual golf partners (so I could
gauge how I was doing relative to them). A few interesting points about
compared with Normal driver
a few yards longer
a few yards shorter
as likely to
finish in play
finish in play
- The best drives are distinctly better with the longer
driver. 10-15 yards is not to be dismissed lightly. Of course, it isn't
my original 25-yard impression; that was my best long driver shots
compared with my typical short driver shots -- the wrong way to compare.
- Most of my on-course shots with the long driver were
shorter than I have come to expect from my normal driver. The few big
winners pulled the average up, but the median was definitely lower.
(You'll find the explanation in the launch monitor tests.)
- To my surprise, I did not lose "straightness" with the
longer driver. I probably hit more fairways with it, even most of my
not-so-good shots. More of my poor shots finished "in play" than I am
used to. I'm not sure how to explain it, but it certainly seems to be
the case -- and it is in keeping with the results from Kenney's study.
launch monitor results.
|My friend Charlie Badami is auditioning launch monitors for
his teaching and clubfitting bay. When I called to see if he was
interested in the experiment, he was using a Flightscope, a highly
respected instrument. I zipped over to his "office" and we did some
first question was whether my computer model for clubhead speed was in
the right ball park. If not, that would explain (a) the disagreement
with Cochran & Stobbs' study and perhaps (b) why the computer model
disagreed with the anecdotal experience of people like Bernie
Baymiller, Danny Seng, and David Dugally.
That did not happen. When I looked at clubhead speed for both drivers
table on the left), the gains due to the longer driver were very close
to what the computer model predicted. On the computer I tweaked the
torques until I got the same
84.4mph from the computer model that I got from the launch monitor.
Then I just changed the club characteristics in the computer model to
match my longer driver. The measured improvement was 3.2mph and the
computer model predicted an improvement of 3.7mph. That is definitely
close enough not to worry about.
On top of that, both the computed and measured difference in clubhead
speed corresponds to about a 10-yard gain in distance -- exactly what our
earlier computer studies suggest.
So the computer model is not debunked by my own swing applied to a long
driver. The model works just fine!
let's turn our attention to ball speed, because that is where distance
comes from. Here is a scatter plot of clubhead speed vs ball speed, and
a tabular summary of what it tells us.
What we see is a tight grouping of clubhead speed for both drivers (the
standard deviation is only 1.8mph), but a much more varied ball speed.
Charlie tells me that most decent golfers have a rather consistent
clubhead speed; this is not unusual. The ball speed variation is
clearly a significant dispersion of "smash factor", which
derives from the quality of the ball strike.
In fact, the long driver produced lower ball speed than the shorter
driver, and substantially so. We see here why my less-than-best drives
on the golf course were usually not as far with the long driver.
|In case there is any doubt about the smash factor
deficiency, we were using face impact tape during the tests. Here are
My driver swing was not very good the day of the launch monitor
testing. In all honesty, I tend to lose my swing after a one or two
dozen hits in an indoor cage. So this is representative of my
performance on a not-very-good driving day. I don't think it contains a
single "best" drive (using the terminology from my on-course
experience); it mostly reflects "typical" and "poor" drives.
Other than the absence of any "best" drives and few "good" drives,
is consistent with what I
observed on the course. The short driver had a reasonable (if not
really good) impact pattern. But unless I hit the ball in the middle of
the long driver
clubface, its shots lost distance compared to the short driver.
Poor impact trumped clubhead speed in generating ball speed.
We can also see the higher trajectory and predominance of heel fades
from the impact tapes.
Charlie is continuing to audition launch monitors. He wants to repeat
the tests with the next one when it arrives. If and when that happens,
I will update this article.
The bottom line for my own use of a longer driver is sort of
Contrary to Bernie Baymiller's experience, I have no problem squaring
the face. Instead, my problem is getting the ball in the center of the clubface.
And I fail to do it often enough that, even though I usually get the
expected higher clubhead speed, I get lower ball speed than my shorter
- My best drives see a gain of 10-15 yards, definitely worthwhile
if it happens more than occasionally.
- Unfortunately, my median drive goes no farther than my shorter
driver, and actually loses distance if I am having an average or poor
day with my driver swing.
- The good news is that I don't give up anything in directional
One final word about the long driver: it seems to be an excellent
training aid. I used it for about ten rounds, then went back to my
normal (44.5") driver. I hit my normal driver better than I had in a
long time. My best drives rivaled my best drives with the long driver
-- close, though probably not quite as big. And I was hitting them
rather consistently. Apparently the swing discipline involved in
hitting the long driver is very beneficial to the use of a more
standard length driver.
Jan 31, 2013