What is the difference between 58R and 60R grips? Both are considered standard sizes, a grip with 0.580″ core will also stretch on a shaft with 0.600″ butt diameter and a 0.600″ core grip will also stay on a shaft with 0.580″ butt. Most people consider the difference to be rather insignificant. However a clubmaker can custom-fit grip sizes by manipulating the core size in combination with the shaft butt diameter.
The core size indicates the inner diameter of the grip. Core sizes help match the correct size grip to the shaft. Most grip manufacturers indicate the core size inside the lip of grip.
To make a Men’s standard grip size, install a grip with 0.600″ core on a shaft with 0.600″ butt diameter or grip with 0.580″ size on a 0.600″ butt shaft.
To make grip slightly oversized, install a 0.580″ core grip on a 0.600″ butt shaft. This makes the grip slightly oversized +1/64″ but smaller than a midsize grip. This practice is done instead of applying additional wrap of masking tape.
To make grip slightly undersized, install a 0.600″ core grip on a 0.580″ but shaft. The grip would be loose without stretching the grip down to hold in place. Stretching the grip further down makes the grip slightly undersized (-) 1/64″. This practice will create a grip size for a man with slightly smaller hands.