.png)
What is RG and Differential for Bowling Balls?
When looking at bowling balls you will notice a couple commonly referenced numbers, RG and differential. Let’s dive into how these numbers affect your ball reaction and how you can use these metrics to make a better decision when buying a new ball.
First, we should define what RG and Differential actually are in technical terms.
RG: RG stands for Radius of Gyration. The RG of a bowling ball tells you when the core is designed to start rolling. The lower the RG, the sooner the ball core will roll. And vice versa, the higher the RG, a later rolling core.
Another good way to understand RG is to view it as a measurement on the bowling ball’s ability to get into a roll.
The higher RG core will have a more difficult time getting into the roll, meaning the ball will project further down the lane before revving up. The lower RG core will want to rev up quicker and earlier.
Bowling Ball RG Range:
What are the correct RG ranges when determining high RG vs to low RG?
Low RG: 2.49 and below
Medium RG: 2.50 - 2.53
High RG: 2.54 and higher
Differential:
Differential, Diff for short, is The difference of the radius of gyration of a bowling ball's X axis compared to the radius of gyration of the ball's Y or Z axis. In other terms, it is basically how much hook potential your ball has.
A high diff bowling ball will try stabilize its core by changing direction to find a better balance. This will cause your bowling ball to have a higher flare, meaning more hook potential. A high diff bowling ball will be more likely to have a strong change of direction at the break point.
A low diff bowling ball will have a more stable spinning core on release, causing lower flare and less hook potential. This type of ball will be more likely to “stand up” at the break point and not change direction as easily.
What are the correct Differential ranges when determining high diff vs low diff?
Low diff: 000 - .029
Medium diff: .030 - .046
High diff: .048 - .060
You can definitely use these numbers next time you are looking for a new bowling ball.
It is important to understand that there are some other factors involved when it comes to ball motion, such as coverstock, core shape, drilling layout, etc.
Please use these numbers as an idea of what the ball motion could be like rather than what it will be.