Symmetrical balls are smoother and more predictable when exiting the pattern and encountering friction compared to that of asymmetrical balls. You will notice there are only 2 variables in core specs when dealing with a symmetrical ball. They are the RG value and Differential. With the new rules that started August 1, 2020 you will really only have to worry about pin placement with symmetrical balls. You will not be able to add a weight hole to add to the overall differential of a ball.
Produces a smoother and more predictable motion when encountering friction.
Typically better for rev dominant players.
With the new rule changes, CG placement will not matter for performance.
Typically, they are better for speed dominant players as they need more help getting the ball to change directions due to their lack of rev rate compared to ball speed. Typically, asymmetrical cores produce a more pronounced and sharper motion when encountering friction compared to symmetrical balls. There are 3 variables in core specs with an asymmetrical ball. They are the same as symmetrical balls but with the added variable of Intermediate Diff. The reason for this added specification is because on asymmetrical balls, there are 3 axis with different RG values. Due to the 3 different axis that asymmetrical balls possess, there are many more layouts that can be achieved with an asymmetrical ball compared to a symmetrical since there is another RG plane that can affect ball motion and the shape the ball makes on the lane.
Produces a more pronounced and sharper motion when encountering friction.
Typically better for speed dominant players.
Added variable of Intermediate Differential allows more layout pssibilities.