A 50mm SB-style insert bearing (flush inner ring on one side) built with #52100 chrome steel races, an injection-molded polyamide cage, rubber seals, C3 clearance, and P6 precision — running on Si3N4 (silicon nitride) ceramic balls instead of steel.
Silicon nitride balls are roughly twice as hard as steel and meaningfully lighter and lower-friction, so they spin freer and run cooler. They're also non-porous and non-magnetic, so they resist corrosion and won't pit or micro-weld to debris the way steel balls can — if anything gets into the bearing, the ceramic balls tend to polish the races smooth again rather than get damaged by it.
New ceramic hybrid bearings need a short break-in period — a dozen or so hard laps — before they're running at full efficiency.
**SOLD Individually, Most Karts Will Require 3**
