STRIKE ZONE / Scott Bailey
Part III: The basic science
of bowling ball physics
Welcome to the third and last article in "The Basic Science of
Bowling Ball Physics" series. If you recall, the first section dealt
with the importance of ball surface type and texture. Part II was a brief
explanation of core design parameters and how they affect your ball
reaction potentials. This combination of ball surface and core design will
dictate about 85 percent of a bowling ball's reaction potential, and it
offers much insight as to the overall characteristic of your bowling ball.
In Part III, we will
discuss the process of drill pattern layouts. Topics to be covered are as
• Release Types.
• Positive Axis
• Mid-Plane or
Vertical Axis Line (VAL).
• Preferred Spin
• High RG Layouts.
• Low RG Layouts.
• Weight Hole
• Common Myths.
The most important factor that will determine your ball reaction is your
physical game. How you release the ball, your ball speed, and the amount
of leverage you create will dictate how much of a ball's reaction
potential is realized.
For instance, a
bowler with high speed and little hand rotation will find it very
difficult to achieve large hooking action and strong back-end. Likewise, a
bowler with slower ball speed and more hand rotation will tend to have
much larger hooking action and stronger back-end hook. This will be true
no matter what reactive ball or drill pattern he/she uses.
Every bowler who
throws a hook releases the ball with a certain degree of axis rotation. If
you release the ball with a straight hand, your axis rotation would be
zero degrees, while releasing the ball with your fingers on the side
produces a 90-degree axis rotation. Most hook bowlers fall between 20 and
70 degrees of axis rotation.
Generally, the more
axis rotation you have, the more your ball will skid in the heads, and the
harder it will turn on the back-end. However, this does not mean that more
axis rotation is always better. This will be determined by the lane
condition on which you compete.
that will determine your ball reaction
is your physical game.
As most of you already know, the harder you throw
the ball, the less it hooks. Very few bowlers, though, understand the
importance of consistent ball speed. The speed your ball travels down the
lane will directly affect its skid length, back-end potential, and pin
Many times I have
seen bowlers get pumped up after throwing a few strikes in a row. As the
adrenaline flows, the ball speed increases until finally they leave a
corner pin on a perceived good shot.
In truth, as the ball
speed increased, so did the skid length, which caused the ball to enter
the pocket at a different angle, thus causing the corner pin. Once again,
please concentrate on maintaining consistent ball speed.
The amount of
leverage created during your release will tend to affect the strength of
the ball roll through the pins. A bowler blessed with good leverage does
not necessarily throw a big hook. I've seen many straight players with
above-average leverage, with Earl Anthony being the best example. Earl's
ball hooked very little, but carried the pins very well. Likewise, many
bowlers with large hooks have poor leverage, greatly reducing their
ability to carry the corner pins.
Leverage is created
through good leg drive and the ball position at the bottom of the swing.
PBA Tour star Walter Ray Williams Jr. is a great example of this. Williams
drives very hard into his slide step, positioning his hand powerfully
behind the ball. His slight outside-to-inside swing plane promotes a flat
angle of attack from the inside, which brings the ball very close to his
ankle at the bottom of the swing. All of these factors create strong
leverage, even though he is considered more of straight player.
Every bowler's ball is released on a certain ball track. The easiest way
to find your ball track is to locate the oil ring on your ball during
practice. This ball track can tell you a lot about how you're releasing
the ball on a given day.
More common ball
tracks include the high ¾ roll, low ¾ roll, semi-spinner, and
full-spinner. Although not very common today, the full-roller track is
still around. For all-around purposes, the best ball track to have today
is a low-to-medium ¾ roll. Before the advent of reactive cover stocks,
the high ¾ track was the best. However, with today's ultra-aggressive
ball designs, very high ¾ tracks can and will tend to hook too early,
reducing the ball's hitting power.
Also important is the
tilt of your track. Track or axis tilt will determine how easily your ball
achieves a roll-out state. More axis tilt will reduce the chances of
roll-out but will hinder performance on a heavily-oiled lane surface. Less
axis tilt will tend to roll-out more, but will roll stronger on heavier
Having more or less
axis tilt is not good or bad. The type of track works better is determined
by the lane environment on which you bowl.
One factor that all
of these tracks have in common is they produce what is called your
Positive Axis Point or PAP. Your PAP is the line that runs through the
center of your ball and is perpendicular to your ball track. Like the
north and south poles on a globe, your ball spins around this line. Your
PAP becomes very important when trying to create drill pattern layouts for
different types of ball reaction potentials.
Also important is the
mid-plane or vertical axis line (VAL). This line runs through your PAP,
perpendicular to the grip mid-line. This will be discussed later in
Every contemporary bowling ball has what is known as a Preferred Spin Axis
or PSA. Where this PSA is located is determined by the shape, size, and
density placement of the ball's core. These factors also will dictate how
powerful the PSA is, and how much effect it will have on the ball
A bowling ball's PSA
is the axis through which the ball would like to spin. In layman's terms,
a sphere that is rotating around an unstable axis will seek a more stable
axis of rotation. The axis the ball seeks is its preferred spin axis. Most
often, this is the X axis or high RG axis, which was discussed in last
month's article on core design. Bowling balls with traditional three-piece
cores or generic two-piece cores exhibit a rather weak PSA. Balls with
more dynamic core shapes and densities will tend to have much stronger
PSAs. A ball with a strong PSA is not always better than one with a weaker
PSA. Which works better for a given bowler is determined by the lane
surface and oil patterns.
The position of the
PSA in relation to your mid-plane and PAP will determine the shape of the
hooking action. There are three basic hook shapes: arc, flip, and hook/stop.
Most bowlers like to see their ball react in one of these fashions.
Knowing which one you'd like to see will help in the drilling layout
I know from
experience that most of you will say the flip reaction is what you like to
see. However, most of the best bowlers in the world today reach optimum
scoring with the hook/stop reaction, à la Walter Ray Williams Jr., Tim
Criss, Mike Aulby, and Norm Duke.
A good pro shop
technician, utilizing knowledge about a specific bowler's physical game,
lane conditions, and a ball's axis migration to its PSA, can very
accurately predict a bowling ball's reaction potential. The two best
examples of this that I know of are Del Warren of AMF and Brian Pursel of
Ebonite International. Both of these gentlemen have a gift for laying out
the perfect ball for a bowler on a given lane condition. Doing this at
their level requires a great deal of knowledge, vast research, and tons of
I would like to think
that I am a competent pro shop technician, but I am constantly amazed at
their level of skill and knowledge. I owe them both a great deal in
helping me learn what I have so far.
Once your pro shop technician has an understanding of the ball reaction
you seek, your Positive Axis Point, and any other pertinent information,
he/she can begin to help you choose the right ball. Consumers must
understand that a drilling layout can only change the ball reaction within
the parameters of that ball.
For instance, a
Columbia Boss has an RG value of about 2.47 on its low RG axis with a
differential RG of .039. This means that the highest RG value around any
axis in the Boss is 2.509, which is still very low.
Therefore, no matter
how this ball is drilled, it will not display High RG reaction
characteristics. It will never roll, for instance, like a Black
Thunderstorm or Ebonite Sea Wolf, regardless of the drill pattern. The
Boss is meant to roll early and strong, and there is nothing your pro shop
technician can do to change that!
At best, drilling
patterns will fine-tune a particular ball reaction, making it slightly
more conducive to the lane surface. Drill patterns will not change the
inherent characteristics of the ball. Please remember that before
purchasing your next ball.
Once you have chosen
the right ball, now is the time to consider the different types of
layouts. For our purposes, drilling layouts will be classified into three
basic categories: high RG layouts, low RG layouts, and leverages.
These categories are outlined below.
High RG Layouts
As a general rule, high RG layouts will tend to have more length through
the pines, and a moderate-to-mild back-end reaction. These patterns work
well for bowlers with slower speeds, or lane conditions with dry heads and
High RG layouts are
characterized by placing the large locator pin farther away from your PAP
or closer to your ball track. As I said, this will increase skid length.
The back-end hook shape will be controlled by the PSA placement.
If you have slow ball
speed, a lesser degree of axis rotation, or if you bowl on lightly-oiled
lanes, you probably will like high RG drilling layouts.
Low RG Layouts
Low RG drill patterns will tend to roll earlier
and produce mild-to-moderate back-end reactions. Bowlers with faster ball
speeds, strong axis rotation, or those bowling on heavy-head and pine oil
with dry back-ends, will benefit most from low RG layouts. Because these
patterns roll earlier and are fairly stable, they are easier to control on
local "house" oil conditions.
Once again, you can
change the hook shape by placing the PSA in different locations relative
to your PAP and mid-plane.
Most bowlers who come to me with a specific layout request most often ask
for a leverage pattern. I assume this is due to the myth that leverage
layouts will skid longer and flip harder on the back-end. This is
definitely not true! Leverage patterns do have the most potential for
overall hooking action, but they will not go longer than the high RG
patterns listed above.
In fact, by
leveraging a strong core design, you run a good risk of making the ball
hook too early due to increased friction from larger amounts of track
flare. If the ball hooks too early, you will definitely lose back-end
reaction, not gain it. Leverage patterns are strictly for heavy-head and
pine oil with carry-down.
can use leverage patterns on drier conditions, but I still don't recommend
it. The simple fact is, with the super high friction cover stocks on
bowling balls today, if you are unable to hook the ball, then chances are
there is some problem in your physical game. If this is the case, you are
better off spending your money on lessons than buying a new
high-performance bowling ball.
That being the case, there are situations where
leverage patterns work very well. If you are trying to create more area
and "open up" an oily lane, a leverage pattern certainly will
help you. Also, if you bowl in tournaments out of this area, you probably
should carry one or two balls with some type of leverage pattern, just in
case you hit a heavy-oil lane condition. As with the other layouts above,
the hook shape is controlled with the PSA.
Some of the patterns listed in this article will require balance holes to
meet ABC/WIBC specifications for positive side and finger weight. While it
is true that drilling a balance hole changes the static balance of the
ball, this is not the reason for the ball reaction change. Placing a
balance hole in the ball changes the RG values around your PAP.
For example, placing
a balance hole in the ball will probably lower the RG value around the
spin axis or PAP. Therefore, placing a balance hole in the ball will make
it spin slightly faster and roll slightly earlier than the same ball
without a balance hole. Small holes drilled deep will lower the RG values
less than larger holes drilled shallow.
The balance hole also
changes the position of the PSA. This fact allows us to slightly increase
or decrease track flare potential in the ball, depending on the balance
hole position in relation to your PAP.
It is important to
remember that balance hole positions are very minor in their influence
on your ball reaction. They are simply a process by which your pro
shop technician can fine-tune your bowling ball.
There are so many misconceptions about bowling and bowling balls that I
cannot begin to cover them all in this article. I have, however, picked
out a few that I believe to be important enough to discuss here:
• Pin-out balls
are better than "pin-in" balls.
For several years
now, many bowlers were incorrectly told that balls with locator pins
farther away from the CG are better. This is simply not true. The bowler's
physical game and the lane conditions ultimately determine which pin
location is better. Pin-in balls will tend to spin faster and be more
controllable on the back-end. Pin-out balls will spin slower and react
more violently on the back-end. Which is better for your game depends on
the environment in which you participate.
high-performance balls carry better than others.
There are many
factors that determine your carry percentage. The most important of which
is pocket entry angle. The simple fact is good pin carry is as much about
proper alignment to the break point as it is about the bowling ball.
Think about this:
Every ball on the market today has produced a 300 game or 800 series for
someone. If your ball is not carrying the pins for you, chances are you're
using it at the wrong time and in the wrong environment.
• Reactive balls
hit too hard.
A bowling ball can
never hit too hard-it can only hit at the wrong angle. During the days of
plastic and rubber balls, a solid pocket shot was about the 17-1/2 board.
Today, because reactive balls have more friction and less deflection, the
solid pocket shot is closer to the 16 board. Therefore, the pocket has
moved slightly to the right. The high-carry percentage shot back then was
"high pocket"; today it's the light-pocket shot.
The next time you rip
the 5-pin into the 7-pin or send a "messenger" headpin across
the lane to take out the 10-pin, ask yourself, Do I really want my ball
to hit weaker?
There you have it,
folks, a three-part crash course in the basics of ball dynamics. I have to
tell you, however, that this series just scratches the surface. Every ball
manufacturer has any number of brilliant engineers and chemists devoted to
optimizing the performance of your bowling ball. New discoveries are made
each day, so things will only get better.
Of course, all the
technology in the world will not turn a bad bowler into a good one. It is
incumbent upon you to prepare yourself properly to take advantage of this
equipment revolution. Seek out a qualified instructor, practice hard, and
devote yourself to improving your game. Then find a pro shop technician
that you can trust-one who can give you a solid hand fit and who
understands the complexities of today's bowling environment. Only then
will you achieve optimum performance.
Arc Reaction - An arc ball reaction is a smooth and continuous hooking
- Axis rotation is the amount of side turn you put on the ball. It is
measured in degrees, starting at zero, which is a straight ball.
Axis Tilt -
Axis tilt is the amount of vertical tilt associated with your axis point.
Balance Hole -
A fourth hole added to your ball to make it legal under ABC regulations. A
balance hole can also be used to fine-tune a particular ball.
Center Line -
The line that runs between your finger holes and through the center of
your thumb hole.
CG - The
center of gravity of your bowling ball. The point on your ball that
designates the exact static center of the ball. It is usually marked with
a small punch mark near the label of the ball.
DRG - The
differential radius of gyration, which is found by measuring the
difference between the low and high RG axes in the ball. DRG is a product
of the mass distribution inside your ball and dictates the amount of track
flare potential in your ball.
- The balance of your bowling ball while in motion (Mass x Distance2).
- A ball reaction style with a very sharp hooking action on the back-end.
- A very effective hook style when used on the right lane conditions. The
bowling ball makes one distinct move towards the pocket then rolls in a
strong end-over-end manner.
Condition - A type of lane condition used in many bowling centers
for their leagues. It usually connotes heavy oil in the middle of the
lane, with dry outside boards and back-ends. A very high-scoring oil
condition for the average bowler.
Mid-Plane - A
line running vertically through your PAP that is perpendicular to the grip
mid-line. The mid-plane and the vertical axis line are the same th
Mid-Line - A
line running horizontally through the center of your grip, perpendicular
to the center line.
PAP (Positive Axis
Point) - The axis line that your ball spins around, based on your
release. Everyone's PAP is slightly different. The PAP is very important
when using exotic drill patterns.
Spin Axis) - The axis line that your ball prefers to spin around,
based on the interior dynamics of the core. This spin axis is usually the
high RG axis.
RG (Radius of
Gyration) - RG is a product of the mass distribution inside the ball.
It will determine the effective spin rate of the ball. Low RG balls have
their mass located closer to the center of the ball. High RG cores have
their mass located farther from the center of the ball.
- The balance of a bowling ball while at rest (Mass x Distance = Force).
Track Flare -
The movement of the ball track caused by an unstable axis of rotation.
This is evidenced by the multiple oil rings on your ball after the
X-Axis - The
highest RG spin axis on a ball. Usually the "Preferred Spin
Y-Axis - The
intermediate spin axis on a ball. Located 6¾" from the X and Z axis.
Z-Axis - The
lowest RG spin axis on a ball. It is usually marked by a large locator
Scott Bailey operates The Strike Zone Professional Bowling Store in
. He can be reached via E-mail at email@example.com.