STD 628 RS Skate Rated "Deep Groove" Bearings 8mm Set of 16

Set of 16 STD Skates 628 RS skate rated "DEEP GROOVE" bearings are specialized, high-performance precision bearings engineered specifically for artistic figure roller skating and quad skates utilizing an 8mm axle diameter. They are sold as a 16-unit set to fully outfit a complete pair of quad roller skates. Unlike standard industrial 628 bearings, these are calibrated via a specific mechanical adjustment to handle the exact physical forces experienced during skating.
 
Radial Clearance: This takes into account the space between the balls and the raceways of the rings. In the Skate Rate calibration, an intentional clearance is left. This prevents the bearing from seizing up when a little dirt gets inside or when heat expands the metals during intense training.
High Lateral Load Capacity: Quad skating, especially figure and artistic skating, applies massive sideways pressure. The deeper raceway grooves prevent the balls from slipping off their tracks or "biting" into the metal casing when taking sharp edges or landing jumps. 
Intentional Radial Clearance: A calculated gap is left between the balls and the inner rings. This prevents the bearings from seizing up when the metal expands due to intense training friction or if microscopic debris breaches the seal. 
Groove Depth Calibration: A bearing calibrated for skating has deeper ball grooves to increase structural stability under impacts (jumps, spins).
Enclosure Type: "RS" indicates a rubber seal on the sides to protect the internal components from dust, dirt, and moisture.
Features premium chrome steel outer and inner rings paired with black ceramic-coated or mirror-polished balls to maximize rolling speed.
Bearing Size: 628 standard metric size (8mm inner diameter × 24mm outer diameter × 8mm width)
 
STD Bearings Ratings Summary
Beginner: Balanced calibration between speed and impact resistance = STANDARD
Precision: Calibration with finer tolerances for maximum inertia (rolls longer without pushing off) = DEEP GROOVE
Competition: Calibration focused on minimal friction, with mirror-polished balls and ceramic coating = CERAMIC