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Dynamics Review August 2018


Welcome to Dynamics Review! In this monthly series, you will see reviews of some of the hottest balls on the market. Let’s face it-bowling is a very complex and technical sport, and understanding ball motion and technology can often sound like it was designed by NASA. So, before diving into the actual reviews, let’s first start by covering a few basic concepts and terms to help you on your journey to not only choosing your next ball but better understanding your ball reaction.

There are three phases of ball motion.As the ball travels down the lane it skids, hooks, and finally rolls.The core of the bowling ball rotates as the ball goes through the different phases of ball motion.In the skid phase the core rotates a minimal amount.When the ball enters the hook phase, this is when the core begins rotating most; the ball slows down and changes direction.S it changes direction it enters the roll phase, at which point it continues on a straight line path from the hook phase (and hopefully toward the pocket!).

Now let’s talk about hook-everybody wants it.The variables that affect hook are: ball speed, revolution rate, ball core, ball cover, surface adjustments, drilling layout and lane condition.

Bowler Ball Speed and Revolution Rate:“Matching” these two variables relative to one another will ultimately enable proper ball motion.When a bowler is speed dominant the ball has less opportunity to slow down and change direction to create hook.Slower ball speed means the ball slows down too early, the core rotates too soon and ball runs out of energy.A revolution dominant bowler causes the ball to change direction earlier than it was intended while a lower revolution rate bowler has difficulty getting the ball in to the hook phase.Though it can be obvious to the eye which “type” of bowler you are, tools such as Bowler ID can help accurately identify the ratio of these two important bowler attributes.

Ball Cores:There are two types of ball cores, symmetrical and asymmetrical.Symmetrical cores are often more mild and normally this creates less track flare.Less track flare means that the core rotates slower as ball (rolls) travels down the lane.This promotes longer skid and later hook or “quick” backend.Asymmetrical cores are often stronger and generally produce a larger amount of track flare.This means the core rotates quicker or earlier as the ball moves down the lane.This is usually associated with stronger, earlier ball motion and promotes strong early hook or “slow” backend.The core characteristics are affected by our next component, the coverstock, and can alter the general performance of the core type.

Coverstocks:There are three types of coverstocks: solid, hybrid, and pearl.A solid coverstock creates earlier ball motion, less skid, smoother backend.These perform best on moderate to high volumes of oil.A hybrid cover is a combination of solid and pearl, moderate amount of skid, stronger hook down lane.Hybrid covers fit best on moderate to light volume of oil.Pearl covers have the latest ball motion, longest slide or skid, stronger backend or hook.A pearl cover is often used on lighter or low volumes of oil, creating a quicker backend.

Surface Adjustments: Changing the surface on your ball is a very powerful tool . Sanding or polishing the cover allows you to manipulate your break point and the shape of your hook. Sanding the surface to a dull finish minimizes the skid phase. This makes the ball hook earlier on the lane, Creating a smooth and continuous motion. Polishing the surface maximizes the skid phase so the ball will hook later down the lane. Normally this creates a stronger, more angular hook on the backend.

Drilling Layouts:Bowling ball layouts create an opportunity to manipulate the technology of the bowling ball through drilling strategically.The distance from the core pin to the positive axis point controls track flare.Controlling the track flare directly affects all phases of ball motion.When the track flare lines are close together this creates longer skid and stronger backend because the core rotates slower, thus leaving the ball with more stored energy.A wider space between the track flare lines indicates the core is rotating and using energy earlier on the lane, thus creating smoother continuous hook.

Manufacturers combine different cores and covers to manipulate when cores rotate/use energy.Depending on your revolution rate and ball speed, certain core and cover combinations will compliment your style as you bowl on ever-changing lane conditions

Lane Conditions:Lane conditions have a dramatic effect on hook potential.Oil is applied to the lane to protect the surface and create challenges.Bowling balls do not hook in the oil; they hook when they encounter friction.The bowler must match their speed and revolution rate with the ball core and cover so the core rotates at the appropriate part of the lane based on the lane condition.

When considering a new bowling ball, you may have noticed manufacturers provide specifications with their products.Bowling ball core dynamics are characterized by three factors:the Radius of Gyration (RG), Differential (Diff), and Intermediate Differential (INT DIFF). Combining the overview of ball cores from the section above with these specifications, we can now apply this conceptual knowledge with the technical components to describe the effect those numbers may have on ball motion.

The RG describes how the mass is distributed in the ball, the way the ball reacts, and when the core rotates going down the lane.Low RG is when the mass is distributed near the center of the ball and creates earlier ball motion.High RG is when the mass is distributed closer to the shell and this creates later ball motion.The scale for RG is 2.46 – 2.80 (low RG 2.46 – 2.49, medium RG 2.50 – 2.53, high RG 2.54 – 2.80).

The Diff indicates the bowling ball’s track flare potential.Minimal track flare creates longer skid and maximum track flare creates stronger hook.The scale for Differential is 0.001 – 0.060 (low 0.001 – 0.020, medium 0.021 – 0.040, high 0.041 – 0.060).

INT DIFF corresponds to the amount of asymmetry of the core.The higher the intermediate differential the greater asymmetry of the core,and the lower the intermediate differential the lower the asymmetry of the core.The higher the intermediate differential, the higher potential for track flare, and thus the ball hooks stronger off the friction.The scale is 0.008 – 0.0370, low int. diff. 0.008 – 0.020, high int. diff 0.021 – 0.0370.When core does not have an intermediate differential number it is symmetrical in shape.

August Review

Core numbers for 15lb balls.

Roto Grip Halo – RG (2.49), DIFF (0.50), INT DIFF (0.018)

Asymmetrical Solid – strong early hook with continuous backend

Hammer Scandal/S – RG (2.48), DIFF (0.054), INT DIFF (N/A)

Symmetrical Hybrid – aggressive midlane with continuous backend

Motive Hydra – RG (2.55), DIFF (0.037), INT DIFF (N/A)

Symmetrical Pearl – long skid with medium backend

REMEMBER: Your revolution rate and ball speed have a dramatic effect on when and how much your ball hooks. The drilling layout is also an important variable that has an influence on your bowling balls motion. Consult your pro shop for options on matching you to a ball for your needs.

Dave Cirigliano is the owner-operator of Bowling Dynamics for the last 31 years. He is a graduate of Don Johnson’s Advanced School of Bowling and currently a USBC Silver Certified Coach. He is also a member of the Arizona State USBC & Metro Phoenix USBC HALL of FAME.

For future reference this article will be posted on my website www.bowlingdynamics.com and facebook page Bowling Dynamics.