Bowling Ball Side Weight
bowlingball.com,
Originally Posted: 2/4/13; Updated: 4/13/21Bowling ball side weight is a term used to refer to the weight difference measured from the left and right halves a bowling ball referenced from the finger holes of the ball.
The United States Bowling Congress (USBC) states that a
bowling ball 10.01 pounds or more may have a
maximum of 3 oz. of top or bottom weight, and 3 oz. each of side, finger or thumb weight.
A DoDo scale is needed to weigh the ball for side weight after drilling.
A ball used without any holes or indentations may not have more than three ounces difference between any two halves of the ball. Balance holes are considered illegal as of August 1st, 2020. Each hole in the ball must be used for gripping purposes on each and every delivery.
A side weight imbalance after a ball is drilled with gripping holes influences bowling ball motion. In modern terminology, side weight is a compatible measurement based upon the Pin placement relative to a bowler’s
Positive Axis Point (PAP) and the Center of Gravity (CG) marking on the surface of the ball.
Side weight may be thought of as a "pulling power" weight when the mass of the ball near the Pin is located near the PAP. The strong side of the ball, so to speak, is the PAP side of the ball and with positive side weight, you will achieve a level of "pulling power" as your ball enters the pocket.
With the variety of modern day core shapes and sizes in high end bowling ball equipment, the degree of side weight is trumped by the drilling layout option a bowler chooses. So long as the final weight of the ball adheres to and conforms with the USBC requirements of one ounce side to side measurement after drilling, a bowling ball is legal to use in sanctioned competition.
Many drilling options used in asymmetric core designed bowling balls create a very high Differential of RG and, therefore, a good deal of track flare potential. The Ratings of Differential and Track Flare are the most important measurements with respect to ball motion in comparison with side weight. Side weight is a by-product of core shape and bowling ball symmetry.
Update from USBC:
ARLINGTON, Texas – After reviewing feedback from
industry partners, the United States Bowling Congress Equipment and
Specifications Committee has revised the implementation dates for the
new bowling ball specifications announced earlier this year.
The Equipment and Specifications Committee determined the specification
allowing increases in static weights for bowling balls without balance
holes will begin this fall to allow for a smoother transition for
bowlers.
Starting Aug. 1, 2018, bowling balls weighing more than
10 pounds will be allowed to have up to three ounces of static side,
thumb or finger weight and up to three ounces of top or bottom weight,
provided the ball does not have a balance hole.
Bowlers still can have a bowling ball with a balance hole until Aug. 1, 2020, but any
balls with a balance hole must stay within the current static weight
specification of one ounce for finger, thumb or side weight, and three
ounces for top or bottom weight.
The specification eliminating the use of balance holes still will go into effect Aug. 1, 2020.
“After hearing from all stakeholders, the committee decided it was the right
move to make the static weight specification an option starting this
fall,” Andrew Cain, chair of the USBC Equipment and Specifications
Committee, said. “Bowlers now have a two-year window to work with their
pro shops to ensure their equipment will meet specifications on Aug. 1,
2020.”
With the elimination of balance holes as of Aug. 1, 2020,
bowlers may have up to five holes for gripping purposes and all gripping
holes must be used on every delivery. A bowler who chooses not to use a
thumb hole would need to mark by scribe, engraver or tool their
intended center of palm with a plus (+) mark to indicate their grip
orientation.
Bowlers who do not use their thumb for delivery and
decide to use the higher static weight specification cannot have a thumb
hole – it would be classified a balance hole – and immediately will be
required to follow the specification requiring them to mark their
intended center of palm.
The USBC Equipment and Specifications Committee did decide the gripping rules that become effective Aug. 1,
2020, will have an exception for house balls, for bowlers who use house
balls and might not have the strength to use all gripping holes.
House balls are defined as balls supplied by the center where the competition
is taking place, have a polyester or basic urethane cover, a
differential RG of less than 0.025 inches and the ball is not
specifically drilled to fit the bowler.
The dates for implementing the new specification for the oil absorption rate of
bowling ball coverstocks do not change. The initial step on the oil
absorption specification will begin Aug. 1, 2018, when bowling ball
manufacturers are required to submit oil absorption data as part of the
USBC bowling ball approval process. The specification requiring a
bowling ball’s oil absorption rate to be more than 2 minutes, 15 seconds
(2:15) for the ball to be approved will take effect Aug. 1, 2020.
However, because all current bowling balls will be grandfathered in regardless
of oil absorption rate, the Equipment Specifications Committee
determined the production of balls that do not meet the 2:15 oil
absorption time limit must be stopped as of Jan. 31, 2022.
The new bowling ball specifications announced in April were designed to
sustain the playing field both currently and in the future.
The Equipment and Specifications Committee has delegated authority from the
USBC Board to make changes to equipment specifications.
