New game-changing rating systems.

To hook or not to hook.
It is no longer a question.

Hook Potential

To find the perfect ball, you need to know exactly what that ball is designed to do. Roto Grip’s new HP system separates our balls into lines based on their hook potential, or HP. The HP4™ line offers products with the most aggressive hook potential. The amount of HP decreases incrementally as the number line decreases, with HP1™ representing balls with the smallest amount of hook potential.

The new HP ball lines make it easier to identify and build a complete tournament arsenal, equipping you to dominate on any lane condition. Or, whether you’re a newcomer looking for your first ball or a bowling veteran looking for a ball that perfectly complements your game or existing arsenal, the new lines help narrow your search to only balls that will give you exactly what you’re looking for.

The ins and outs of Guts, Grit and Grime™.

The revolutionary Guts, Grit and Grime ball rating scale uses a weighted formula to account for several different measured variables of the weight block and/or core (Guts), the coverstock (Grit) and the lane condition on which the ball achieves maximum performance (Grime). This advanced system gives you a better, quicker understanding of each Roto Grip bowling ball and how it compares to others in the Roto Grip family.


We look at items that include the radius of gyration at a multitude of positions (most measure only three), the shape and direction of the RG planes of this particular shape, the differential, and more. Higher numbers equate to a more aggressive core or weight block shape which produces more total ball motion.


We take into consideration the highly complex chemistry involved in producing our cutting-edge coverstocks. Oil displacement and pliability are two of the measurable elements. The number here relates to the strength of the coverstock, and higher values indicate more aggressive shell materials.


This will be a letter indicating the amount of lane conditioner this ball is designed to handle. Heavy Oil (H), Medium-Heavy (MH), Medium (M), Medium-Light (ML), and Light (L) are your options here. Remember that you can adjust the surface or layout of any Roto Grip ball so that it works across a variety of lane conditions.