R188-ZZ Miniature Ball Bearing For Precision Instruments & RC Models | 6.35×12.7×3.175 mm

The R2-6-2RS is a high-performance imperial miniature bearing specifically engineered for environments where exposure to moisture, dust, or fine particulates is a concern. Featuring a dual-contact rubber seal ("2RS") design, this bearing provides a superior airtight enclosure compared to metal shields. The synthetic rubber seals are reinforced with steel inserts, ensuring that the factory-applied grease remains securely inside the raceways while effectively blocking external contaminants. With a standard 1/8-inch bore and a 3/8-inch outer diameter, the R2-6-2RS is the ideal choice for outdoor equipment, small power tools, and high-precision mechanical assemblies operating in demanding conditions.

The R2-5-ZZ is a precision-engineered, inch-series miniature deep groove ball bearing designed for applications where rotational stability and radial clearance control are paramount. With a 1/8" bore diameter, this model is slightly more robust than the ultra-micro series, offering a balanced power-to-size ratio. It is equipped with dual metallic shields (ZZ) that provide a physical barrier against workplace debris while maintaining a non-contact interface with the inner ring to prevent friction-induced heat. This specialized construction ensures the R2-5-ZZ remains the preferred choice for high-speed micro-motors and sensitive transmission systems.

The R2-5-2RS is a highly resilient inch-series miniature deep groove ball bearing engineered to deliver reliable rotation in environments prone to dust and moisture. Featuring a standard 1/8" inner diameter, this micro bearing is equipped with dual contact rubber seals (2RS) crafted from durable NBR (Nitrile Butadiene Rubber). Unlike standard metal shields, these contact seals create a physical barrier against external particle ingress and fluid splashes. This heavily shielded architecture effectively locks in premium factory grease while preventing abrasive contaminants from reaching the raceways, making the R2-5-2RS an essential component for demanding outdoor applications and exposed micro-mechanisms.

The R2-5 Open is a precision-engineered, inch-dimensional miniature deep groove ball bearing developed specifically for applications demanding absolute minimum rotational resistance. With a standard 1/8" bore diameter, this bearing utilizes an entirely unshielded (open) architecture. By eliminating the physical barriers of shields or rubber seals, the R2-5 Open achieves a zero-contact environment that eradicates frictional drag. This design is highly favored for mechanisms housed within clean, enclosed environments or oil-bath systems, where maximum RPM and rapid heat dissipation are critical for system performance.

The R3-ZZ is a high-precision, double-shielded single-row miniature ball bearing engineered for exceptional rotational performance in applications where low starting torque and high speeds are critical. Unlike contact rubber seals, this model features dual non-contact pressed steel shields (ZZ) that effectively retain the factory grease and block larger dust particles without generating additional frictional resistance. Designed with fractional inch dimensions—a 3/16-inch bore, 1/2-inch outer diameter, and 0.196-inch width—the R3-ZZ provides a perfect mechanical solution for compact devices, micro-motors, and high-frequency appliances.

The R22-ZZ is a single-row inch-series deep groove ball bearing fitted with double pressed-steel shields (ZZ), purpose-built for applications where reliable dust exclusion and low-maintenance operation are priorities. With a 1-3/8" (34.925 mm) bore, 2-1/2" (63.5 mm) outer diameter, and 9/16" (14.288 mm) width, it serves as a direct-fit solution across North American inch-dimensioned machinery platforms. The metal-shield configuration keeps friction torque lower than rubber-sealed equivalents, making this bearing a preferred selection for higher-speed assemblies including motors, textile drives, CNC spindles, conveyor roller heads, and agricultural equipment where light contamination protection is needed without sacrificing rotational performance.

The R22 is the base open configuration of the R-series inch-dimensioned Conrad-type ball bearing, offered without shields or seals for applications where lubrication access, higher operating speeds, or field-selectable lubricants take priority over self-contained contamination protection. With a 1-3/8" (34.925 mm) bore, 2-1/2" (63.5 mm) outer diameter, and 7/16" (11.112 mm) width — notably slimmer than the shielded R22-ZZ or sealed R22-2RS variants — the open design is the preferred fit for enclosed gearboxes, oil-bath housings, clean-environment motor shafts, and any application where lubrication is managed externally by the machine's own system. It ships without grease and accepts both oil and grease lubrication, giving maintenance engineers full control over lubricant type and repack intervals.

The R22-2RS is a single-row, inch-dimensioned deep groove ball bearing sealed on both sides with contact rubber seals, designed for operation in environments where contamination control and lubricant retention are the primary concerns. Sharing the same 1-3/8" (34.925 mm) bore, 2-1/2" (63.5 mm) outer diameter, and 9/16" (14.288 mm) width as the R22 family, the 2RS variant distinguishes itself through its contact-lip rubber seal design, which actively wipes against the inner ring to block dust, moisture, and fine particles from reaching the raceway. Factory pre-greased and permanently sealed, it is suited for pump drives, agricultural machinery, textile equipment, packaging lines, and any inch-shaft application where re-lubrication access is limited or impractical.