Understanding Radius of Gyration

Looking through our product line, you will notice a wide variety of RG and Diff values. These numbers can be overwhelming, so we are going to break them down to help you understand what they mean for your ball reaction. Today, we are going to start with RG, or the Radius of Gyration.

Think of the core as the engine of the ball when going down the lane and reading the lane pattern. The lower the RG, the quicker the “engine” revs up, reading the pattern. The higher the RG, the slower the ball revs up, producing more length down the lane before trying to change directions. The RG values vary in our product line from 2.47 (low) all the way up to 2.57 (high) with other cores falling in between. A higher RG means that the mass of the core is spread further from the center of the core and a lower RG means that the mass is more centrally located.

Think of a figure skater spinning in place on the ice. When the skater has their mass more centrally located and tucked with their arms closer to their body, they will spin faster. This would be like a lower RG core which likes to spin faster on the lane. When the skater has their mass spread out more such as with their arms away from their body, they spin slower.

Typically, in today’s environments, you may see a lot of lower RG balls being thrown on the fresh or more challenging conditions. This is usually because the bowler has more confidence in seeing their ball pick up sooner and control the lanes better. On higher friction or easier patterns, you will see more higher RG balls going down the lane as they produce more skid before making their move off the friction down lane. Obviously, there are many other factors that go into the motion a ball makes not only in the oil but as well as off the friction (i.e. coverstock type, surface, bowlers style, differential of core, etc.) and we will get to those at a later date.

We have huge RG diversity in our product line and we encourage you to check out our ball lineup to explore each ball page and gain a better understanding of the equipment available.