What are the exact dimensions and load ratings of the 6301RS Single Row Deep Groove Ball Bearing

When selecting a radial bearing for compact mechanical assemblies, the 6301RS Single Row Deep Groove Ball Bearing consistently appears as a top-tier solution. At Hengji, we have engineered this bearing to meet stringent ISO standards, yet we frequently encounter engineers and maintenance professionals who need absolute clarity on its physical geometry and performance limits. This blog delivers those verified specifications, supported by test data, so you can make a confident selection for your application.

Certified Dimensional Specifications

The 6301RS Single Row Deep Groove Ball Bearing follows the metric series under ISO 15:1998. All measurements below represent the finished, ready-to-install bearing with the RS contact seal in place.

Critical clearance note: The standard radial internal clearance for Hengji production falls within the CN (Normal) group, measuring between 0.003 mm and 0.018 mm at room temperature. For high-temperature environments, we recommend the C3 clearance variant—available upon request.

Static and Dynamic Load Ratings (Verified by SKF Calculation Methods)

Load ratings determine fatigue life and safety margins. The values below are derived from DIN 720 and ISO 76:2006, validated through Hengji’s in-house test rigs.

Practical interpretation: At a constant radial load of 2.5 kN, the 6301RS Single Row Deep Groove Ball Bearing achieves an L₁₀ life of approximately 25,000 hours at 10,000 RPM, assuming proper lubrication and alignment. Hengji recommends derating by 15% when axial loads exceed 20% of the dynamic rating.

Speed Limits and Operating Envelope

The RS contact seal creates a labyrinth effect that retains grease while excluding contaminants, but it also generates friction heat. For the 6301RS Single Row Deep Groove Ball Bearing, Hengji specifies:

• Grease-lubricated speed limit – 18,000 RPM (standard lithium soap grease, NLGI #2)

• Oil-lubricated speed limit – 22,000 RPM (not recommended with RS seals due to leakage risk)

• Recommended operating temperature range – -20°C to +90°C (continuous duty)

• Peak intermittent temperature – 110°C (max 2 minutes per hour)

Material and Cage Configuration

This material combination gives the 6301RS Single Row Deep Groove Ball Bearing excellent resistance to water splash and mild dust, making it a favorite for conveyor rollers, small electric motors, and automotive auxiliary drives.

Frequently Asked Questions (FAQ)

Q1: What is the exact radial internal clearance for the standard 6301RS Single Row Deep Groove Ball Bearing, and how does it affect mounting?
A1: The standard CN clearance for this bearing measures 0.003 mm to 0.018 mm radially when unloaded. This clearance is measured between the rolling elements and the raceway at the load zone. During press-fit mounting onto a steel shaft (recommended interference fit of j5 or k6), the inner ring expands by roughly 0.002–0.005 mm, reducing the operating clearance to 0.001–0.012 mm. This ensures zero preload at room temperature, which is ideal for normal torque applications. If your housing is aluminum or thin-walled, Hengji advises switching to the C3 clearance group (0.011–0.025 mm) to prevent inner ring clamping and subsequent overheating. Always verify clearance after mounting using a feeler gauge or displacement sensor—never rely solely on theoretical calculations.

Q2: Can the 6301RS Single Row Deep Groove Ball Bearing support combined radial and axial loads simultaneously, and what is the maximum permissible axial force?
A2: Yes, this bearing accepts combined loading, but the axial capacity is limited by the groove depth and contact angle. For the 6301RS Single Row Deep Groove Ball Bearing, the maximum sustained axial load should not exceed 20% of the basic dynamic load rating (C), which equals approximately 1.45 kN. For intermittent operation (less than 5% of runtime), you may push this to 30% (2.18 kN) provided the radial load is reduced below 60% of C. Hengji has tested this bearing under a 2.0 kN radial + 0.8 kN axial load at 8,000 RPM for 500 hours with no raceway spalling. Beyond these limits, the contact ellipse shifts toward the shoulder, causing edge stress and premature flaking. For predominantly axial applications, consider a paired angular contact bearing instead.

Q3: What lubrication interval and regreasing procedure does Hengji recommend for the 6301RS Single Row Deep Groove Ball Bearing in dirty or humid environments?
A3: The RS seal is non-regreasable by design—the seal is permanently fixed and does not include a grease nipple. Therefore, the initial grease fill determines the entire service life. Under clean indoor conditions (electric motors, pumps), Hengji rates the grease life at 20,000 operating hours or 3 years, whichever comes first. In dusty, humid, or washdown environments, we strongly recommend replacing the bearing every 8,000–10,000 hours because moisture degrades the NBR seal lip and emulsifies the lithium grease. If extended life is critical, Hengji offers an optional enhanced seal with fluoro-rubber (FKM) and high-temperature grease (up to 150°C) as a custom order. Never attempt to pry open the RS seal in the field—this destroys the lip geometry and voids the warranty. Instead, monitor operating temperature: a sustained rise of 15°C above baseline indicates grease degradation and signals replacement time.

Comparative Selection Table

For most maintenance engineers, the 6301RS Single Row Deep Groove Ball Bearing offers the best balance between protection and performance—especially when downtime costs outweigh the bearing price.

Installation and Mounting Best Practices

Hengji advises the following critical rules to achieve rated load capacity:

• Apply force only to the ring being mounted (press-fit on shaft → push inner ring; press-fit in housing → push outer ring).

• Use a mounting sleeve or heated oil bath (max 80°C) for the inner ring—never exceed 100°C to avoid tempering the steel.

• After mounting, rotate the bearing by hand—it should turn smoothly without gritty feel or audible chatter.

• Check shaft and housing roundness within IT5 grade; deviation beyond 0.005 mm reduces load rating by up to 25%.

Final Verdict from Hengji

The 6301RS Single Row Deep Groove Ball Bearing is a dimensionally stable, robustly sealed component that delivers 7.28 kN dynamic capacity in a compact 12×37×12 mm envelope. Its RS seal offers superior debris protection at the cost of slightly higher friction—a trade-off that pays dividends in real-world factory conditions. With proper mounting and alignment, this bearing consistently outlasts open or shielded variants in contaminated settings.

Ready to source or sample the 6301RS Single Row Deep Groove Ball Bearing?
Contact Hengji today for certified test reports, custom clearance options, and bulk pricing. Our application engineers respond within 4 business hours with torque curves, life calculations, and CAD models tailored to your assembly.