Core Design The Mass Bias

[Daryl]

On asymmetrical balls the mass bias is marked 90 degrees from the pin. When looking at core shapes this mass bias appears to be a protrusion out of the core shape. An example would be the Radical Katana Strike core. If it is this extra mass on the side of a core that creates the mass bias why does drilling a hole into the core taking away mass from the side of the core as in the old balance holes move the position of the mass bias toward that hole instead of away from the hole? I may be just missing something or misinterpreting something.

[EricHartwell]

Rather than call it Mass Bias it is is the PSA, Positive Spin Axis.

The balance holes/thumb holes change the shape, creating/changing Asymmetry.
The thumb hole in a Symmetrical ball creates the PSA location.

Take a look at some of Storm's designs.
The PSA (Mass Bias) is actually a void in the core.
One example that came to mind first...

https://www.stormbowling.com/crux-1

Protrusions or voids contribute to Asymmetry.

It is not about extra mass.
It is about the Shape. The core shape defines the ball motion.