Full Ceramic MR63-MR148-603-699 Miniature Ball Bearings ZrO2 Zirconia Premium

Match the bearing's inner diameter (ID) to your shaft diameter, the outer diameter (OD) to your housing bore, and the width to the available axial space. All three dimensions are listed in each variant name in the format ID × OD × Thickness (mm). If you are replacing an existing bearing, the series number (e.g., 608, MR84) is usually stamped on the bearing face and can be matched directly to the variant list.

Hybrid ceramic bearings use ceramic balls in steel races, which still corrode and conduct electricity through the races. Full ceramic bearings — like these ZrO2 units — have no steel components at all, so they are fully corrosion-resistant, fully non-conductive, and fully non-magnetic. The trade-off is that full ceramic bearings are generally more brittle under shock loads than steel or hybrid designs, so they are best suited to smooth, continuous-rotation applications rather than heavy impact environments.

Yes. ZrO2 zirconia ceramic does not rust or corrode in fresh water, salt water, or most mild aqueous environments. These bearings are commonly used in fishing reels, underwater ROVs, pool equipment, and marine instruments. For submerged applications, run them dry or with a water-compatible lubricant; avoid petroleum greases that can wash out quickly.

ZrO2 ceramic retains its mechanical properties at temperatures that would soften or anneal bearing steel. In dry, unlubricated operation, these bearings can typically function up to approximately 400 °C (752 °F). If a lubricant is used, the effective upper limit is determined by the lubricant's thermal rating, not the ceramic. Always verify the specific thermal requirements of your application before selecting a lubricant.

Full ceramic miniature bearings are widely used in RC motors, drone motor bells, inline skate wheels, and skateboard trucks. The key is matching the bearing series to your component's specification. The 608 (8 × 22 × 7 mm) is the standard skateboard/inline skate bearing. RC and drone motors typically use MR series or 6xx series bearings — check your motor's documentation or measure the existing bearing to confirm the correct size.

ZrO2 ceramic has a lower coefficient of friction than steel and can run dry in many low-load, low-speed applications. For higher speeds or loads, a light synthetic oil or PTFE-based grease is recommended. Avoid heavy petroleum greases in high-RPM applications as they increase drag. In corrosive or wet environments, use a lubricant rated for that exposure. Do not use lubricants containing chlorinated compounds, which can attack ceramic surfaces over time.

The MR series (MR63, MR74, MR84, etc.) is a miniature bearing designation where the number encodes the OD and ID in millimeters — these are very small bearings typically used in precision instruments, micro motors, and RC components. The 6xx series (603–609) follows the standard ISO deep-groove ball bearing numbering for slightly larger miniature sizes. The 68x and 69x series are narrow and extra-narrow variants of the 6xx series respectively, offering a smaller OD for the same bore size. All series in this listing share the same ZrO2 full ceramic construction.