These Balls Aren’t for Juggling – Bowling Ball Characteristics

Bowling balls may seem simple to the common eye, but they are much more than solid spheres with finger holes in them. The balls are designed to perform on various surfaces, and to compliment the style and strength of each individual bowler. The wooden lanes used in the game of bowling are treated daily with mineral oil. The mineral oil is used to protect the lanes from the action of the bowling balls. There are various types of bowling balls available, but they all have the same general characteristics. The circumference of the average bowling ball is usually between 27.002 and 27.704 inches.

The balls have varying weights to accommodate the varying strengths of many consumers. A bowling ball can weigh from 6 pounds to 16 pounds. The weight of the ball encompasses everything from the coverstock (material) to the core, which contains the weight block. The coverstock is the material used to make the outer surface of a bowling ball. There are four types of coverstock used in the making of bowling balls. The four coverstocks are polyester, urethane, resin, and particle. The material of the coverstock determines how a ball will roll. In general, the harder the coverstock, the straighter the ball will roll down the runway. Polyester balls are usually recommended for beginners and casual bowlers. On the other hand, urethane balls are the high-performance alternatives for professionals.

Polyester bowling balls have been available since the 1960s. They tend to skid, and roll straight with a small hook, and are most suitable for extremely dry lanes. In the 1970s bowling manufacturers developed urethane coverstocks, which are softer than polyester. The softer material produces more friction and hooks more than polyester balls. Resin balls are stronger than bowling balls made of other materials. The balls are known for their sharper hooks and greater power, which gives them the greatest strike potential. The resin balls are reserved for the most advanced bowlers, and can be used in all lane conditions. The first resin particles were added to urethane coverstocks in the 1990s. The resin particle additive increased the friction between the balls and the lane, and increased the hook potential of the ball. The resin balls evolved into particle balls when manufactures added ceramics and glass. The added textures increased friction and gave the ball more grip in oil.

The core of a bowling ball is the part of the ball with the largest concentration of mass. The sophistication and position of the core of a bowling ball are key features in the dynamics of a bowling ball. The sophistication and position can be explained by the radius of gyration (RG), which is a property used to determine how easily the ball will rotate. RG is the measurement of where the weight is located inside of the ball (relative the ball’s center). The core position, size, shape and density can adjust the RG. For example, a centralized core locates the weight in the center of the ball resulting in a low RG ball. If the core is placed off-center, the weight of the ball is shifted resulting in a high RG bowling ball, or what is known as a cover-heavy ball. Generally, the lower the RG, the quicker the ball will pick up its revolutions.

Three holes encompass the common bowling ball; two are for the fingers, and one is for the thumb. Usually inserting all three fingers into the ball holds a bowling ball. Alternatively, only the fingertips are placed into the ball. Using the fingertips may give less grip, but a bowler will be able to lift the ball better, and create more hook. There may also be a fourth, non-gripping hole (balance hole) in the bowling ball, which is used to fine tune the ball’s reaction. Twelve holes are allowed in each ball; one for each finger and thumb on both hands, one hole to bring a ball into static weight tolerances, and a “mill” hole to check the hardness of the coverstock just below the surface of the ball.