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When a seized or noisy bearing brings your build to a halt, the right replacement needs to arrive ready to run — no break-in drama, no wobble. Whether you are a maker rebuilding a 3D printer carriage, an RC hobbyist refreshing a drivetrain, or a technician servicing small motors, these miniature ball bearings are sized and sealed to drop straight into tight spaces where standard bearings simply will not fit.
Each bearing is manufactured from carbon steel with dual metal shields (ZZ designation), covering inner diameters from 3 mm to 9 mm (approximately 0.12 in to 0.35 in) and outer diameters from 10 mm to 26 mm (approximately 0.39 in to 1.02 in). Thickness ranges from 4 mm to 8 mm (approximately 0.16 in to 0.31 in) depending on the selected size. Available models include 604ZZ, 605ZZ, 606ZZ, 607ZZ, 608ZZ, 623ZZ, 624ZZ, 625ZZ, 626ZZ, 628ZZ, 629ZZ, 685ZZ, and 688ZZ.
Typical use cases include: replacing worn 608ZZ bearings in skateboard wheels and inline skates; fitting 623ZZ or 624ZZ bearings into fidget spinners, small fans, and pen plotters; and sourcing 625ZZ or 688ZZ bearings for CNC router spindles, servo mechanisms, and robotic joint assemblies where compact envelope and consistent radial clearance are critical.
Both sides are enclosed with pressed-steel shields that block debris and retain grease without the added drag of rubber seals — ideal for dry or lightly lubricated environments.
Carbon steel races and balls deliver solid load capacity and dimensional consistency across the full size range, from the compact 623ZZ up to the wider 629ZZ.
Choose from 604ZZ through 629ZZ and 685ZZ / 688ZZ to cover inner diameters of 3, 4, 5, 6, 7, 8, and 9 mm — one listing, one checkout, the exact size you need.
Pre-greased and assembled to tight radial clearance tolerances, these bearings spin quietly under light-to-moderate radial loads — a must for 3D printer linear rails and small motor shafts.
Order 1, 10, 20, 50, or 100 pieces per size — whether you need a single replacement or a workshop stock of spares for ongoing projects.
Dimensions conform to standard ZZ miniature bearing specifications, making these a direct swap for OEM bearings in RC vehicles, power tools, fans, and hobby equipment.
| Material | Carbon Steel (races & balls) |
|---|---|
| Shield Type | Dual metal shield (ZZ) |
| Inner Diameter Range | 3 mm – 9 mm (approx. 0.12 in – 0.35 in) |
| Outer Diameter Range | 10 mm – 26 mm (approx. 0.39 in – 1.02 in) |
| Thickness Range | 4 mm – 8 mm (approx. 0.16 in – 0.31 in) |
| Available Models | 604ZZ, 605ZZ, 606ZZ, 607ZZ, 608ZZ, 623ZZ, 624ZZ, 625ZZ, 626ZZ, 628ZZ, 629ZZ, 685ZZ, 688ZZ |
| Lubrication | Pre-greased |
| Load Type | Radial (light to moderate) |
| Pack Quantity Options | 1 / 10 / 20 / 50 / 100 PCS |
| Weight (per piece) | See variant options |
Match the three dimensions in the variant name: Inner Diameter × Outer Diameter × Thickness. Measure your shaft (inner bore) and housing (outer seat) with calipers, then select the model whose numbers match. For example, 608ZZ fits an 8 mm shaft in a 22 mm housing with 7 mm width.
ZZ indicates dual metal (steel) shields on both sides of the bearing. The shields keep grease in and contaminants out without the friction increase associated with rubber contact seals (RS or 2RS). They are well-suited for moderate-speed, low-contamination environments.
Carbon steel bearings offer moderate corrosion resistance when kept dry and lightly lubricated. They are not recommended for continuous exposure to water, salt spray, or aggressive chemicals. For wet or outdoor environments, consider stainless steel (SS) variants instead.
Yes. The 608ZZ (8 × 22 × 7 mm) is a direct fit for many extruder idler pulleys and Y-axis rod ends. The 625ZZ (5 × 16 × 5 mm) is commonly used in V-slot wheel assemblies. Both are available in this listing — select the matching size and quantity from the variant dropdowns.
These miniature bearings are designed for light-to-moderate radial loads typical of hobby, maker, and small-appliance applications. They are not rated for heavy industrial axial loads. Exact dynamic and static load ratings vary by model size; contact us if you need specific load data for your application.
No. Each bearing comes pre-greased from the factory. For most hobby and light-duty applications, no additional lubrication is needed at installation. If operating at elevated temperatures or speeds, you may supplement with a compatible bearing grease after removing the shields.
For a single repair or prototype, the 1 PCS option keeps cost low. For ongoing projects — such as maintaining a fleet of RC vehicles or stocking a makerspace — the 10, 20, or 50 PCS packs offer a lower per-unit cost. The 100 PCS pack is suited for small-batch production or resale.
