A round grip is round in circumference. A ribbed grip has a raised rib down the back side of the grip to serves as reminder to get your hands in the same place consistently when take your grip. The rib fits in your finger tips. With .580" and .600" core size grips the number references the size of the hole on the inside of the grip. The 2 grips have the same outside diameter but the .580" core size grip has a smaller inside diameter hole to match up to .580" butt diameter shafts. The .600" core size grips have a larger inside diameter hole to match up the a .600" butt diameter shaft size. A .580" core size grip installed onto a .580" butt diameter shaft will create a standard size grip, which is .900" measured at 2" down from the top edge of the end cap. A .600" core size grip installed onto a .600" butt diameter shaft will create a standard size grip, .900". If you look at the grip weights you will see that the .580" core size grip is 2 grams heavier. This is because it has the same outside diameter as the .600" core size grip but with a smaller inside diameter the wall of the .580" core size grips have thicker walls and will be heavier. The .580" core size grips were the ones that came first. Some companies like Titleist and Mizuno will install .580" core size grips on a .600" butt diameter shaft on their stock clubs which creates a + 1/64" oversize grip or .915".
Date published: 2016-08-29