How To Tell The Difference Between Symmetric and Asymmetric Bowling Balls

Written By: bowlingball.com | Written On: Tuesday, January 6, 2015 | Updated On: Tuesday, July 12, 2022

bowlingball.com, Originally Posted: 1/6/2015; Updated: 7/21/2022
Bowling ball symmetry is all about bowling ball core construction and ultimately the varying differential ratios.
The term differential in a bowling ball can be defined as the difference between the maximum and minimum Radius of Gyration (RG).
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.
In layman’s terms, symmetrical drilled bowling 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.
The mass distribution in a 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 good skid distance in the front end of a lane.
Low RG numbers indicate that the ball mass is distributed more towards the center (center heavy) which promotes less front end skid and an earlier roll through the front part of the lane.
The differential of RG measurement (the short term is differential) is related to a bowling ball's track flare potential.
The higher the differential, 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.