Activities Sports & Athletics The All-Important Bowling-Ball Core What Makes a Bowling Ball Behave the Way it Does? Share PINTEREST Email Print Inside every bowling ball is a core that can affect the spin and hook as it rolls down a lane. Peter Cade / Getty Images Sports & Athletics Bowling Basics Technique Baseball Basketball Bicycling Billiards Bodybuilding Boxing Car Racing Cheerleading Cricket Extreme Sports Football Golf Gymnastics Ice Hockey Martial Arts Professional Wrestling Skateboarding Skating Paintball Soccer Swimming & Diving Table Tennis Tennis Track & Field Volleyball Other Activities Learn More By Jef Goodger Jef Goodger is a bowling enthusiast who works as a writer, commentator, and producer for Xtra Frames, the Professional Bowlers Association streaming service. His writings feature on various websites, such as Pinterest. our editorial process Jef Goodger Updated April 29, 2018 There are a lot of different factors that influence how a bowling ball acts. The weight is perhaps the most obvious to a beginner, as it's fairly easy to determine the difference between a ball that weighs more than a ball that doesn't. However, outside of the fact some bowlers can more easily throw a lighter ball and vice versa, the weight has less to do with how a ball hooks or doesn't hook than some other factors. The cover stock is highly influential on how a ball rolls, as the three main categories of cover stocks (plastic, urethane and reactive resin, listed in order from the least traction to the most traction) determine how well the ball grabs the lane and either helps the ball hook or prevents it from hooking. In some cases, bowlers want the ball to roll straight, and grab a ball with a plastic cover stock to deflect the oil away. In other instances, bowlers want the ball to soak up the oil and hook, so they'll use a reactive-resin cover stock. Another important aspect of how a ball behaves is the layout. The layout refers to where the finger holes are drilled into the ball. Since a bowling ball is spherical, it might seem like it wouldn't matter where the holes go. However, it matters tremendously. Why? The core. The Weight Block That Is the Core The core of a bowling ball is in a specific shape, and thus the weight is distributed differently throughout the ball. This is why drilling the holes in one spot can result in a stronger (that is, more hook) reaction and drilling them in another spot results in a weaker reaction. Depending on the type of core and in which direction it points, a bowler can get a multitude of different reactions using the same piece of equipment, changing only the layout. Symmetrical and Asymmetrical Cores There are two types of bowling-ball cores. A symmetrical core is the same all the way around one axis, although it is not necessarily the same around another. That is, it may be symmetrical horizontally, but not vertically. In that case, though, there is a marking on the bowling ball (called the pin) that denotes where the center of that symmetry is. This lets your ball driller know how to properly layout the ball and take advantage of the symmetry. Asymmetrical cores have a greater distribution of weight in one spot than another. Often, these balls work well for bowlers who struggle with putting a significant number of revolutions on their shots, as well as in specific situations for high-level bowlers. Neither core type is necessarily better than the other, but as with everything in bowling, each is designed for a specific purpose. How to Find the Core in a Bowling Ball We're not talking about busting open a bowling ball and finding the core (although if you do have an old ball you don't need anymore, it can be an interesting experiment). How do you find where the core is in a brand new bowling ball, thus telling you how to lay it out? Mentioned above, the pin tells you a lot. When bowling balls are made, the core is affixed to a machine as the rest of the ball is formed around it. When that's complete, the ball (and core) are cut loose, and all that remains of the core is the pin that attached it the core to the machine. This pin is usually a different color than the rest of the ball and is clearly denoted, usually by a circle less than a quarter inch in diameter. Using this mark, along with other markings on the ball, your ball driller can design the layout right for you and that ball.