In the last article, we talked about the variables that you, the bowler, can control in determining how much a ball hooks (read part 1 here). Hopefully, if you read it, you rushed out and measured your axis of rotation, axis tilt, rev rate, and ball speed so you have a better understanding of how this affects you. In this article, we will take a look at the bowling ball variables. You know, all that mumbo jumbo that ball companies post on their website to make their ball look impressive. Well I am here to clear up some of that confusion and show you that it’s not that complicated after all. Once you figure all this out you can compare similar models and pick the one that looks the coolest.
A bowling ball is basically made of two parts: the coverstock and the core. Let me start by explaining a little about how balls are built. After the ball is designed by engineers on a CAD program and tested for real world results, production begins. The core is made first. A simple pancake weight block design is made by pouring a dense material in the bottom of a mold that is then filled with a lighter material to complete the core. The core is suspended inside a larger mold with a riser pin and then the coverstock (shell) material is poured around it. After it cures, the mold is removed, and the ball is rounded and smoothed in a resurfacing machine. It is then engraved, boxed, and shipped to your local pro shop. With a high-performance ball, a step is added to build the weight block first which is then inserted into an outer core mold or directly into the full-size ball mold. More advanced balls can include multiple densities in the core and weight block extensions to alter the core dynamics. The density of the coverstock will be the same and the gross weight is altered by changing the core, which is why you will see different core numbers in different weight balls. This is a simplistic explanation but will give you the general idea. Although all ball manufacturers are automated, there is still quite a bit of labor involved to finish a quality product.
A lot of thought and energy is put into the design of a bowling ball’s weight block, but the most important element to consider when looking for your next ball is the coverstock. The cover is the predominant factor in ball reaction and therefore in ball selection. When balls are designed, matching the proper core for each cover is a critical design element. The manufacturer does this. You need to determine what type of cover you need and then start looking at the core. It is important to note that many coverstocks can be altered to change their reaction, but the core cannot, per se… Technically you change the core every time you put a hole in the ball, so there are things a driller can do to alter the core. This will be the topic of my next article so I can’t give away too much.
There are basically 3 types of coverstock materials: polyester, urethane and reactive resin. You may get some different labels due to semantics, but a polyester ball is usually referred to as plastic and this type of cover has the least friction and hooks the least. The only benefit to plastic is price. But in terms of performance, they do not measure up. And now every manufacturer offers low price reactive balls that have plenty of performance and do not cost much more than a plastic ball. Urethane balls have more friction than plastic and offer better performance. They are very durable and easier to control than a reactive ball, especially if you have slow speed. Reactive resin is the ball of choice for most. They have explosive pin action because of the friction they create on the backend and steep entry angle. Different manufacturers do have some unique reaction characteristics, but presently all make very high quality bowling balls with good performance. The friction of the coverstock is the main factor to match a ball to a player on a given lane condition. As your skill level improves, more balls with various reactions are needed to match the lane conditions. Remember that the cover contacts the lane surface and how this cover is prepared has a tremendous influence on the ball reaction. The cover on the ball changes every time you throw it. If you have a ball with a heavily sanded finish, the ball surface will get smoother each time you throw it. Conversely, if the ball surface is very shiny and smooth, then it will get rougher each time you throw it. There are many products on the market available to keep your ball surface maintained properly. You should use a different product for each different ball, otherwise you will make all your balls react close to the same. And it is best to use products specifically designed for a bowling ball. Check with your I.B.P.S.I.A. certified pro shop for proper ball maintenance.
Read 'Maintain Your Bowling Ball's Life and Performance'
The core is what confuses most people because terms like radius of gyration and differential are used to describe the core. I will try to explain these things as they apply to ball reaction without getting into physics. A higher radius of gyration (r/g) will make the ball slide further down the lane before it starts to hook. A lower r/g gets the ball rolling sooner. The differential is what creates track flare. Higher differential equals more flare. More flare means more hook because it exposes a fresh surface of the ball to contact the lane on the backend. Differential is a more critical component of ball reaction than r/g for most bowlers. You need to understand your own player variables when trying to determine how all of this affects your ball selection. One word of advice is don’t get too caught up in minor differences in these numbers.
Most ball manufacturers offer ball reaction charts that compares their ball reactions within their respective company. They are good tools to use when shopping for a ball. One of the best things you can do is determine the characteristics of one of your old reliable balls to use as a benchmark when shopping for a new one. I know it can be overwhelming when you walk in the pro shop and see the ball wall, but maybe with a little more understanding you can simplify the process.