Bowling Ball Symmetry
Understanding
bowling ball symmetry can be confusing and highly technical but it also can be a help in selecting your next bowling ball.
Bowling ball symmetry varies from ball to ball based upon certain factors engineered into the ball construction process. Familiarizing yourself with bowling ball symmetry is also a step in understanding bowling ball motion.
Let's begin by examining the primary technical differences between symmetric and asymmetric balls:
1. Symmetrical Core (undrilled) - A ball where the
RG (radius of gyration) values of the Y (high RG) and Z (intermediate RG) axes of the ball do not differ by more than 5% of the total differential of the ball.
2. Asymmetrical Core (undrilled) - A ball where the RG (radius of gyration) values of the Y (high RG) and Z (intermediate RG) axes of the ball differ by more than 5% of the total differential of the ball.
Technical information is often difficult to understand for most of us laymen bowlers so our staff at
bowlingball.com wishes to simply state that symmetrical drilled balls yield small differential ratios. Small differential ratios will produce a smooth, controllable motion when compared to an asymmetrical ball.
In comparison, asymmetrical drilled balls show a defined, angular motion. These balls can create more area at the break point and will respond to friction faster at the break point than symmetrical balls.
Continuing in our examination of symmetry, it has been proven through United States Bowling Association (USBC) field studies that all drilled bowling balls are asymmetrical, whether they are symmetrical or asymmetrical before drilling.
More technical terms we hear discussed about modern
bowling balls which directly relate to a
bowling ball symmetry are as follows:
The term differential in a bowling ball can be defined as the difference between the maximum and minimum Radius of Gyration.
Radius of gyration, RG, is measured in inches and is the distance from the axis of rotation at which the total mass of a body might be concentrated without changing its moment of inertia.
More simply put, the distribution of mass in the bowling ball relates to the measurement of RG.
High RG numbers indicate that the ball mass is distributed more towards the cover (cover heavy) which promotes length through the front end of the bowling lane.
Low RG numbers indicate that the ball mass is distributed more towards the center (center heavy) which promotes an earlier roll through the front part of the lane.
The differential of RG measurement, a measurement which indicates the bowling ball's track flare potential, shows us that the higher the number, the greater the track flare potential.
What does this mean? The larger the differential and track flare, the more
asymmetrical the bowling ball. Conversely, the smaller the differential and track flare, the less asymmetrical the ball.
What can we learn from this? When you set out to choose a new bowling ball, pay attention to the track flare, differential, and the core symmetry ratings. Based upon your objective, you can select a ball which is designed to be compatible to the ball motion you seek.
For example, a low flare, low differential,
symmetric ball will produce a controllable ball motion and achieve a smooth and even arc from the break point to the pocket.
A high flare, high differential, asymmetric ball which will create length through the front end and a strong and angular back end hook motion.
Of course, you can attenuate the ball motion by either choosing a strong drilling layout or a control drilling layout. It is important to consult with your pro shop professional before choosing a new ball so you can use this technology and the
drilling layout to your best advantage.
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bowlingball.com.
