The radius of Gyration (RG) is a measurement of the bowling ball. It gauges the distance from the axis of rotation. The bowling balls with a higher RG number has extensive length. But the bowling balls with lower RG numbers can move faster and hook within a short time. So, if you want to hook early, you need to have the bowling ball with a lower RG number. But if you want more length, you should prefer the higher RG number.