Hey 01kay,
Top weight is known as a static weight that makes the top side of the ball heavier than the bottom side. It can be achieved by extra weight or density in the weightblock or flip blocks that are attached to the top of a weightblock. It can also be achieved by drilling the hole (where the filler goes, which ends up being the pin) deeper so that the weightblock actually falls closer to the topside of the ball during production. This will produce more weight on it's top side, hence top weight. By having one side of the ball heavier, it will no longer roll evenly like a ball bearing but have a loping effect as it rolls down the lane to help create momentum. Hope this helps explain..
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Rick Leong
Ten Pins Pro Shop
Track Intl. - Amateur/Pro Shop Staff
Vise Inserts Staff