Bowling Ball Top Weight
bowlingball.com, Originally Posted: 2/3/2013; Updated: 7/26/2021
Bowling ball top weight is a term used to refer to the weight difference measured from the top half of a bowling ball compared to the bottom half of the ball.
The United States Bowling Congress (USBC) states that a bowling ball
10.01 pounds or more may have not more than three ounces static side, thumb and finger weight after the holes are drilled.
A DoDo scale, the scale used to measure static weight of bowling balls, is needed to weigh the ball for top weight after drilling. (The use of balance holes is now considered illegal per USBC rules)
A top weight imbalance after a ball is drilled with gripping holes influences bowling ball motion
. Top weight is created by core designs
developed by manufacturers.
In modern terminology, top weight is a compatible measurement based upon the Radius of Gyration (RG) of a bowling ball.
RG can be described as a measurement by some manufacturers in a range from 2.460" to 2.800", but some companies have converted them to a 1-10 scale to help give the consumer a better frame of reference. These numbers describe the distribution of mass in the given bowling ball and RG is an account of the location of that mass inside the given bowling ball.
High RG numbers indicate that the ball's mass is distributed more towards the cover (cover heavy) which promotes length through the heads of the bowling lane. High top weight balls influence ball motion in much the same way.
Low RG numbers and low top weight measurements indicate that the ball’s mass is distributed more toward the center (center heavy) which promotes an earlier roll through the front part of the lane.
Medium RG describes sufficient bowling ball skid length to reach the mid-lane before transitioning into the hook phase of overall motion.