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Friday, August 17, 2012
3Jack Experiments With Shortening The Driver Shaft
of the questions I get and I often see on message boards is about shortening the
length of the driver. As most people know, the driver shaft lengths from OEM’s
are usually in the range of 45-1/4” to 46-1/2” long. However, according to Tom
Wishon’s booklet ’12 Myths That Could Wreck Your Game’, the average length of a
driver on Tour for each of the last 5 years has only been 44-1/2”
The idea behind the longer driver shafts is that the longer the
shaft will equate to more clubhead speed which will allow the golfer to hit it
longer. The main problems I see is that the long shafts often influence the
golfer’s address position and cause the golfer to make swing compensations to
deal with the shaft being too long. The other problem is that even if the golfer
can address the ball reasonably well, they can have difficulty timing a shaft
that is long in length.
I had debated this myself, but I didn’t feel I
could quite trust recommended lengths from other fitters not named Tom Wishon
(or Richard Kempton http://www.theclubdoctors.co.uk/). And the book that I had
read about driver shaft fitting from Wishon was his 2006 ‘The Search For the
Perfect Driver.’ The book is a great book, IMO, but some of the information
needed to be updated. I was not quite into his recommended length for a driver
based on wrist-to-floor measurement because it came out very short in length
(around 43-1/4” long). My guess is that from what I read in the book, it
appeared to be based upon a golfer using a steel shaft instead of the longer
graphite shaft. Steel shafts weigh much more than graphite and back then
graphite shafts were difficult to figure out. But now with Shaft Bend Profile
technology, there is really no reason to use steel shafts in a driver IMO.
The booklet is free and can be found here. I highly recommend reading
this and it’s an easy read.
to table 2 on page 10 and you’ll find a recommended length for a driver and
5-iron based upon your wrist to floor measurement. I determined that I need a
driver around 44-3/8” long. However, there were several factors I had to
consider before doing this.
There are some minor spec differences like the loft and 1/8”
difference in the length. The shafts are slightly different in weight. The
Aldila RIP Beta has a stiffer butt section which makes the club *feel* stiffer
and more ‘boardy.’ I felt that the loft was too low for me and the shaft was too
boardy, so I got a higher lofted driver with the UST Mamiya shaft.
idea was then to take Driver #1 with the Aldila shaft, trim it down to 44-3/8”
long, match the MOI to the longer driver and analyze the
MOI AND WEIGHT
There was a 1/8”
difference in shaft length when I started out. The shafts had a 2 gram
difference in weight. So when I started out with these drivers, their MOI with
NO weight added to the head, was roughly the same at 2,790 kg/cm^2. I then added
about 3 grams of lead tape to the hosel to each to get them to match to 2,825
kg/cm^2. I have determined that MOI is pretty much spot on for my optimal
I don’t have the bend profile information for the UST Mamiya shaft
as that has not been added to Wishon’s database. My assumption is that the
Aldila has a stiffer butt section and has a little more weight towards the tip
section than the UST Mamiya shaft. Otherwise, from a weight perspective there’s
not much of a difference between the two and my objectives where to figure out
what differences would there be in clubhead speed and attack angle, if
When I trimmed the Aldila RIP Beta from the butt end to get the club
at 44-3/8” long, that made the club ¾-inch shorter than the UST Mamiya shaft.
This also drastically reduced the MOI.
So the Aldila Shaft went
from (w/no lead tape):
45-inches: 319 grams, 2790
44-3/8 inches: 317 grams, 2,680
Now remember, I want to get the MOI to 2,825 kg/cm^2. In order to
get the club from 2,680 to 2,825, that meant I had to add 12 grams of lead tape
around the hosel. And this is how it affected the total static
Hence, the Aldila the shaft is
shorter, but since I matched the MOI of the two clubs, the shorter club is 8
grams heavier in static weight.
Thus, if you want to trim your own driver
shaft or get a new shaft and make it shorter…and IF you want to get the MOI the
same as your longer shafted driver, you can do it. But you MUST take into
account that the shorter driver WILL weigh more in the process of matching the
MOI to the longer driver shaft.
though the shorter driver weighed 8-grams more than the longer driver, according
to Wishon he sees on average, approximately 1 mph of clubhead speed difference
between clubs that have a 25 gram difference. So my feeling was that the shorter
club weighing 8-grams more would be rather negligible with relation to clubhead
In the end, I found that the difference in clubhead speed was
about 0.5 to 1.0 mph between the two drivers with the longer UST Mamiya shaft
being faster in clubhead speed.
My theory is this. Wishon has stated
that you really don’t see a difference in clubhead speed until there’s a shaft
length difference of more than +1/2-inch. So with the difference in shaft length
being 3/4-inch along with an 8-gram static weight difference, that is why the
clubhead speed in the shorter driver was about 1 mph slower.
other theory is perhaps the distribution of the weight in the shaft may have
made a difference as well.
not see any difference in attack angle with either driver. My original
hypothesis was that perhaps drivers that are too long for a golfer would cause a
steeper attack angle because they would feel like they have to un-cock the
wrists earlier in the downswing or it would feel like they would hit the turf
behind the ball.
Instead, I saw virtually no difference. I was keeping my
attack angles in the -0.5 to -2.0° downward range. I will say that my shallowest
attack angle, +0.8° was done with the shorter 44-3/8” Aldila driver. But I would
hit shots altering between clubs and see no difference in attack angles.
It’s difficult to judge with range
balls. Sometimes they would show a spin rate as high as 4,000 rpm’s. Other times
the spin rate was at 1,700 rpms. I think in general my spin rates are in the
2,400 to 3,000 rpm range and I did not see any difference with either
ACCURACY AND CONSISTENCY
the clubhead speed was about 1 mph slower with the shorter Aldila shaft and the
attack angle and spin rate was the same, I really needed to see a difference in
accuracy and consistency with the shorter shaft to decide if it was worth trying
a shorter shafted driver.
Here is where the shorter driver won hands
down. Not only on well struck shots, but with mis-hits as well. Essentially, the
longer driver shaft would have the ball fly much more offline on inaccurate
shots. It was much mjore difficult to control the initial direction of the ball
flight with the longer driver.
What I also found interesting is the
launch angle was much better with the shorter driver and the shaft did not feel
boardy or too stiff.
This is peculiar because like I mentioned earlier,
the shorter driver was in a lower lofted 9° clubhead that I had replaced with a
10° loft. Now the launch angle was virtually the same or within 0.5° from each
What surprised me was that the shorter Aldila RIP Beta shaft no
longer felt too stiff or boardy. I have the shaft bend profile and in general
it’s a fairly common shaft bend profile for an X-Stiff shaft, but it is
noticeably stiffer in the butt section which makes the shaft feel boardy.
Recently, somebody asked Tom Wishon of the effects tip trimming, often
called ‘tipping’, have on the shaft’s bend profile. Here is what Tom
There are some very predictable things as well as a little bit of
weirdness surrounding what happens to frequency machine readings when you
increase the tip trim on a shaft.
In all of our
work to look at this using the Auditor frequency analyzer and the same bend
profile measurements that we use for all bend profile data work for our software
program, most definitely all of the measurement zones from 41" down to 16" do
increase in frequency when you tip trim more off a shaft.
have seen that when you do the 11" beam measurement, when you tip an additional
amount from the shaft, the 11" measurement either stays the same or will
DECREASE. This to us is VERY STRANGE. It should go up just like all the other
bend profile measurement points. But it doesn't and to be totally honest with
you, I don't know why and neither do any of the other shaft design experts that
I have asked about this too. Logic says if you cut more of the smallest diameter
part of the shaft, and then you recreate the same beam length in the
measurement, at the 11" beam you should be clamping the shaft on what is now a
larger diameter part of the shaft. And that means the shaft section sticking out
11" from the clamp consists of a larger diameter part of the shaft and less of
the weakest part of the shaft - so the freq should be going up.
reality it has to get stiffer at the tip end when you tip trim more. You're
cutting off more of the weakest part of the shaft leaving more of the stiffer
part. So in reality supported by golfer hit testing, we can tell you that yes,
additional tip trimming will stiffen the WHOLE shaft. why the freq analyzer
shows this for the 41 to 16 beam length measurements but not for the 11
measurement, I can't tell you
Wishon does their shaft bend profiles, they measure the frequency of the shaft
in 6 different locations from the 41 inch mark (butt end) to the 11 inch point
(tip end). For iron shafts, they measure 5 different locations starting at 36
inches to 11 inches because iron shafts are shorter in raw length than driver
Wishon’s point is that when a shaft is tip trimmed, the very
bottom measurement of the tip section gets softer and the rest of the driver
shaft gets stiffer. Why? They do not know at this point.
So my theory is
when you trim more from the butt end, perhaps the opposite happens with the very
end of the butt section getting softer. Either way, I believe that by making the
Aldila shaft shorter in length, the initial launch improved tremendously, from
directional launch to vertical launch.
WHERE TO GO FROM
the experiment has piqued my interest in going to a shorter shaft. I would trade
a possible 1 mph or less clubhead speed for better launch conditions and more
accuracy and consistency. However, I do not think using the same UST Mamiya
Shaft Model is the answer.
While the lead tape on the hosel is a bit
gaudy looking, I would also worry about the lead tape coming loose and having to
deal with that in the course of a round. And according to Wishon, you start to
see a difference in face angle measurements once you add 11 grams to the hosel.
Here I would be adding more like 12-13 grams.
My solution is to find a
similar shaft model, but at a heavier weight. The next best solution seems to be
the UST Mamiya ProForce VTS Red 7x shaft. This shaft is practically the same
bend profile according to UST as the Silver 6x model. But, it weighs 76 grams,
which is about 9-10 grams heavier than the Aldila RIP Beta shaft. I have the Red
7x in my 3-wood. Thus, I hope to put the Red 7x in the 10° head, get a little
higher launch angle, be better directionally and have more consistency and only
have to add 3-4 grams of lead tape to the hosel.
So here is the rundown for going to a
shorter driver shaft:
1. Affects the weight and MOI of the
2. If you match MOI to a longer driver, the longer driver will
have a lighter static weight
3. Hopefully the shorter shaft will produce
better launch conditions to improve accuracy and consistency
4. The trick
is to figure out if the increased accuracy and consistency will outweigh any
possible lost in clubhead speed.
5. You may have to go to a heavier model
shaft with the same bend profile in order to play with driver with a shorter