The balance hole is an additional hole in the bowling ball that is not used for clamping purposes. The balance holes are mainly used to make the ball have a static weight in accordance with the specifications of current USBC devices. Once a bowling ball has been drilled, there are still options to refine the reaction for the player. The balance hole can affect the bowling ball response depending on the size and position of the hole.
Historically, the higher the balance hole compared to the midline, the more it reduced the likelihood of a bowling ball burst. The lower the hole in the balance, the more likely it is for a bowling ball to burst. Not all balancing holes in the same position will have the same effect with the bowling ball. There are other variables that will affect the way they change the performance of bowling balls.
Low RG means that most of the volume is at the center. Higher RG means that most of the volume is located away from the center. Lower RG balls will need less energy to change direction. They will move faster and roll sooner. Higher RG balls require more energy to change directions. They will forward slower and roll back later.
Each ball will have both low RG axis and high RG axis. It is important to note that the pin is the surface symbol for the low RG x axis of a bowling ball. Generally, 6 3/4 ″ from the pin will be the high Y axis of the bowling ball. The distance from the x-axis to the balance hole will be important in determining the degree and type of effect of the balance hole on the response of a bowling ball. The distance somewhere in the middle will have little or no effect.