Flat Bottom V (FBV), Radius of Hollow (ROH) or ProSharp Z-Channel FAQs

BAHR 2020 updated Skate Sharpening & Profiling Infographic

Current list of all skate sharpening hollows & Prosharp profiling templates we offer – Click to see services we offer!


The revolutionary FBV® (Flat Bottom V®) patented skate sharpening system from Blackstone® gives you competitive advantages like you’ve never experienced before. Superior endurance. Greater power. Enhanced agility. Better control. These are just a few of the improvements skaters from recreational leagues to the pros are reporting with this new blade sharpening technique. In fact, research conducted by The International Ice Hockey Research Academy at the University of Ottawa, under the direction of Dr. T. Blaine Hoshizaki, supports the benefits players are noticing: “The results in this study definitely confirm that the Blackstone® innovation is easily perceived and recognized by the subjects as having a performance benefit.”

Blackstone Skate Sharpening machines are used by Stanley Cup Champions

Radius Of Hollow – (ROH)

Radius of Hollow (ROH) is the conventional “old” way of sharpening hockey & figure skates. It is the size in inches of the circular pattern applied to the bottom of the ice skate blades to provide two distinct edges. The ROH (r) is also referred to as a groove, a hollow grind or a ground radius. The selection of a ROH has a direct effect on a skater’s bite angle and therefore performance. A 1/2” or 5/8″ ROH is considered standard. However, lower and higher ROH are also used. Higher ROH results in lower bite angles and conversely, lower ROH’s result in higher bite angles.


Flat Bottom V – (FBV)

Skate Sharpening Chart- Whats best for YOUR needs?

 The Flat Bottom V is a new way of sharpening skates. This innovation from Blackstone Sports provides more advantages in comparison to the ROH.

FBV Pro’s
• Better gliding and turning abilities
• Smoother and more dynamic actions
• Less fatique – difference you could feel instantly!
• Excellent performance in combination with contouring
• Runners last longer (less material removed per sharpening)
• Faster skating than with ROH sharpening (less drag)
• Ideal for young players (easier to stop, better use of edges)

FBV Con’s

• Sharpening Edge does not last as long as standard ROH on STOCK steel that comes with your skates. 
• Some skaters say, “it feels like skating on ball bearings!”
• FBV needs straight blades in order to get even sharp edges along the blade
• FBV sharpening requires more skills than ROH sharpening (Type of grinding wheel, honing,
finishing, dressing, skateholder adjustments and contouring knowledge is more
important than for a ROH sharpening. It is also more time consuming for sharpeners)

When asking for a FBV®, a skater will ask for a 90/75 or a 100/75, etc. The first number is the width of the flat part ‘d’ of the blade. The second number is the height ‘h’ between the edges of the blade and the flat area of the blade.

STANDARD FBV EDGE is 100/50, equivalent to 1/2″ ROH (Combination of GLIDE + BITE)

Contact BAHR or stop by to learn more about your sharpening options.

It is the most important part of your game, we are help to educate and assist in maximizing your potential.



ProSharp’s Z-Channel – BAHR – Not offering this service

  • Reduces Friction with Less Blade Touching the Ice
  • Increases Grip by Creating Two Interior Edges
  • Reduce your ROH by 20% to Equal Equivalent ROH
  • For All Types of Skaters
  • Not offering this service because we only have ONE Prosharp machine.

Shallower ROH’s add glide speed and reduce fatigue by allowing the skater to be more on top of the ice.  Efficient skater’s work with the ice, not against it!



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