Radius of hollow describes the groove sharpened into the bottom of an ice skate blade. Sparx explains that a smaller radius cuts a deeper hollow with more bite, while a larger radius is shallower and offers more glide. The most common traditional cuts on its guide are 1/2 inch and 5/8 inch; use your current setting as a reference and treat any change as a personal equipment choice.
Radius of hollow, often shortened to ROH, describes the groove ground into an ice skate blade. The cut changes the balance between bite and glide: Sparx says smaller radii make a deeper hollow, while larger radii make a shallower one. Compare the traditional cut your skates already use with the exact option offered by the sharpener or skate shop.
Compare common traditional hollows
| Traditional radius | Typical feel described by Sparx |
|---|---|
| 1/2 inch | Deeper hollow and more bite; one of Sparx’s common cuts, recommended for most youth players. |
| 5/8 inch | Shallower hollow and more glide; another common traditional cut. |
The right choice depends on the skater’s preference, and one setting does not fit every player. Keep a note of the current hollow so you can describe it when requesting the next sharpening.
Know which sharpening type is being discussed
Sparx Radius Rings produce traditional hollows. Sparx describes its FIRE Ring as a flat-bottom hollow with radius edges, which uses a different shape. If you are comparing a traditional ROH with a flat-bottom system, check the sharpener or shop’s terminology before you ask for a change.
Related guides
Official sources
Checked November 5, 2026.
Common questions
What does radius of hollow mean on hockey skates?
It is the radius used to grind the hollow, or groove, into the bottom of a blade. Sparx describes the groove depth as the distinction behind its radius choices.
Is a 1/2-inch or 5/8-inch hollow deeper?
The 1/2-inch radius makes a deeper hollow than the 5/8-inch radius. Sparx describes a smaller radius as more bite and a larger one as more glide.
What radius of hollow should a beginner use?
There is no single setting for every player. Sparx calls 1/2 inch its most common radius and recommends it for most youth players, then a larger radius as the player gets larger. Ask the skate shop what setting your skates currently use before changing it.
Is radius of hollow the same as a flat-bottom cut?
No. Sparx describes Radius Rings as producing a traditional hollow and its FIRE Rings as producing a flat-bottom hollow with radius edges. Check the sharpening system's own terminology when comparing options.