OK, so we started out with the basics in Part 1 of the Coverstock story. Now let’s get into it a little more.

Coverstock Technologies Recap
We briefly explained from least hook to most: plastic, urethane, and reactive resin. That’s the simplest way to explain these coverstocks in relative terms. However, a person with in-depth knowledge can argue different parts of the statements I made because there are many factors that come into play that will dictate which ball might hook more, etc.

Let’s get into the water…
OK, we were in the wading pool so let’s get into the deeper water!
Hardness
The hardest coverstock is the plastic one. The softest will be the resins. Without diving into the deep end, it is part of what contributes to the ball hooking vs gliding in the oil. The simplest way I can describe it is envisioning the following: Go out to your driveway or sidewalk, spin a marble across the ground. Then spin a tennis ball across the ground. You will notice the marble will go further before it spins away into the grass or street. The tennis ball will jump to one side immediately. It’s very soft and has tons of friction as compared to the smooth, hard glass surface of a marble.
Porosity
This is another factor when it comes to whether a ball will hook more or less. The harder ball like plastic is not very porous. It does not absorb oil so the oil will sit right on the cover. Throw one down the middle of the lane and feel how slick your ball is when it comes back. Urethane will be softer and more porous than a plastic ball and thus will hook much more than a plastic ball. After throwing a urethane ball, you will still tend to get it back with plenty of oil on it, just not as much as the plastic ball. A resin ball will be the softest and most porous. The more porous, the more it will hook. It starts to absorb the oil into the coverstock, thereby creating more friction as it goes down lane. Sometimes when you get a reactive resin ball back from the ball return, you hardly see any oil. You can see the rate of absorption with your own eyes! It is one of the major factors that affect ball motion per the USBC ball motion study.
Surface Roughness
While this is microscopic, this is the number one factor that affects the ball motion. To keep this simple, the rougher the coverstock is, the more friction created, thus the more hook is created. Picture the tennis ball vs marble again. Another way to look at it; imagine the surface of the bowling ball as the Earth. You could have plains on it or you could have the Rockies. Having the Rockies with lots of peaks and valleys will create more friction because the surface is rougher. If the surface of the ball looks like the Great Plains, then it will be smooth and hook less because there is less friction. The Motion study separates out the affect of the peaks from the valleys but this is probably too much detail. Generally speaking, the more expensive balls will tend to have high surface roughness and thus hook more.

OK, let’s talk about the lanes a little
On-Lane Friction Basically, the motion study determines how much speed is lost as the ball goes down the lane due to friction. The lane can be oiled with varying patterns and lengths. This will be a major factor in how much a particular bowling ball hooks. As the ball slows down, it has a chance to hook. This is where it gets really interesting. You’ll have to read the next couple of articles to see it 🙂

In the next couple of articles, we’ll talk about “Hook Shape”, different types of reactive coverstocks, and adjusting surfaces…Stay tuned!