Imbalance and Influence on a Balls Reaction

Any imbalance will effect a ball (within the parameters of the many outside influences). The bowling ball center of gravity, or CG, is the heaviest point of balance when the manufacturer weighs the ball. Manufacturers scribe a point, or identifying logo (an Eye of the Storm logo on Storm Bowling balls, a bowling hand on a Columbia300 ball, a Bulls Eye on Ebonite balls, or simple dots on others) to identify a beginning point to place the centerline of the grip (the layout of a ball).
Placing the gripping holes in relationship to the CG creates static imbalances. Static imbalance or a difference from one side of the ball to the opposite side (positive or negative side weight, finger or thumb weight) can be a gross difference of only an ounce in heavier bowling balls. So, the manipulation of top weight (leaving up to the allowable 3 ounces) or the weight removal of a portion of, all of, or more than the top weight (resulting in bottom weight) in the drilling process, can potentially come into play for some bowlers on some lane conditions. Up to 7 pound plus weight blocks, in heavier balls, still impact ball reaction way more than the ounce to 3 ounces of static imbalance.
Static imbalance influences ball reaction (minimally). The degree of influence is the responsibility of the ball driller.
For example, if you throw hard, (and have a decent rev rate, a typical axis tilt and rotation) and the lane is drier, the maximum top weight in a drilled ball of 3 ounces, might cause the ball to skid a little further but to hook violently. The same ball with more surface, adjusting the roughness of the cover stock of the ball, might hook early, burn up and roll out.
Same ball, with a smoother surface, shined up, with ball speed, on more oil might skid for days.
Players, their unique skills (speed, rev rate, tilt, rotation), and the lanes current state of condition (oily, medium, light, dry) all come into play when choosing to maximize top weight, lessen or minimize top weight or seek bottom weight when drilling a bowling ball.
Often, I choose more top weight to benefit slower players or players seeking later ball reaction. Top weight influences the down lane reaction. But, again, more top weight might make a ball unplayable on a lane with more oil.
Layout and imbalances are tools to shape the down lane action of a ball. Ball surface helps manage the front part of the lane (rougher for more oil or more ball speed, smoother/shiny for slower speed, less oil).
Friedl is 18 Years a Chicago Area Pro Shop Operator (Revolutions Pro Shops - http://www.revbowl.com) and Coach. International Pro Shop and Instructors Association (IBPSIA) Hands On Training Certified, Former Bowling Center Operator - (17 years), IBPSIA Charter and Continuing member (17 years), Bowling Writers Association of America (BWAA) member, US Bowling Coaches Association member, Bowling Proprietors Associations of America Management School presenter, IBPSIA Convention presenter, "Bowlers Journal International" Magazine contributor, "Pro Shop Operator" Magazine contributor.