Miniature Wear Carbon Steel Single Deep groove ball bearings Radial Various size

Match the three-number dimension string (bore × OD × width, all in mm) printed on your existing bearing or listed in your equipment's service manual. The bearing type designation (e.g., 625ZZ) encodes the bore and series — the first digit after the series prefix indicates bore size for most 6xx bearings. Cross-check with the Size option in this listing before adding to cart.

ZZ bearings use pressed metal shields on both sides. They retain grease and block coarse particles but allow a small gap at the inner ring, making them suitable for dry or lightly contaminated environments and higher-speed applications where rubber seal drag is undesirable. RS/2RS bearings use contact rubber seals that provide better contamination exclusion but generate slightly more friction and heat at high RPM.

Deep groove ball bearings are primarily designed for radial loads. They can accommodate moderate axial loads in both directions — typically up to 30–50% of the dynamic radial load rating depending on the specific size. For applications where axial load is the dominant force, a dedicated thrust bearing or angular contact bearing is more appropriate.

Yes, all ZZ-shielded bearings in this listing are factory-greased before the shields are pressed in. Because the metal shields are not designed for easy removal without distortion, field re-lubrication is not practical. For applications requiring periodic re-greasing, consider open or rubber-sealed (2RS) variants that allow shield removal.

For 3D printer extruder idlers and carriage wheels, 625ZZ (5×16×5 mm) and 624ZZ (4×13×5 mm) are the most common replacements. For RC car differentials and gearboxes, 6700ZZ (10×15×4 mm) and 6800ZZ (10×19×5 mm) are frequently specified. Always verify the bore, OD, and width against your specific model's documentation.

Carbon steel bearings offer moderate corrosion resistance suitable for indoor, dry, or lightly oiled environments. They are not recommended for continuous exposure to water, salt spray, or aggressive chemicals. For wet or corrosive environments, stainless steel (AISI 440C) bearings with the same ZZ designation are the appropriate alternative.

If you are replacing a single failed bearing in an existing machine, the 1 pcs option lets you get back up and running without excess stock. If you are building a new assembly, running a batch of repairs, or want spares on hand for a frequently serviced machine, the 10 pcs option offers a lower per-unit cost. Both options ship the identical bearing — only the quantity differs.