The MRC (SKF) R4 is a small single-row deep groove radial ball bearing manufactured to inch dimensions.

This type of bearing is designed for applications where:

• Shaft size is very small
• Installation space is limited
• Smooth and low-friction rotation is required
• High rotational speed is important
• Precision shaft support is needed

Nominal dimensions are:

Bore Diameter: 0.2500 in / 1/4 in / 6.350 mm

Outside Diameter: 0.6250 in / 5/8 in / 15.875 mm

Width: approximately 0.1960 in / approximately 5.00 mm

The R4 series belongs to a miniature imperial bearing family. Because suffixes such as R4A, R4AZ, R4FF, R4-ZZ, R4-2RS, or R4-2RSR may indicate different outside diameters, widths, or closure configurations, the complete bearing designation should always be checked before replacement.

⚙️ Applications

• Miniature electric motors
• Electronic equipment
• Measuring instruments
• Medical devices
• RC cars and RC mechanisms
• Precision mechanical assemblies
• Small rollers
• Small pumps
• Miniature fans
• Legacy inch-size machinery

🎯 Benefits

✔ Compact miniature bearing

✔ Inch-series dimensional format

✔ Low-friction deep groove design

✔ Suitable for high-speed rotation

✔ Fits 1/4-inch shafts

✔ Ideal for precision and space-limited equipment

✔ Supports radial load efficiently

✔ Can support light axial load in both directions

✔ Cross-reference assistance available

🧠 Technical Insight

• MRC R4 Bearing Reference
• Miniature Inch-Series Ball Bearing
• Single-Row Deep Groove Radial Design
• 1/4-Inch Bore
• 5/8-Inch Outside Diameter
• Approx. 0.196-Inch Width
• Dynamic Load Rating Approx. 1,470 N
• Static Load Rating Approx. 618 N

✅ Key Features

• MRC (SKF) Miniature Bearing
• Model R4
• Single-Row Deep Groove Design
• Inch-Series Construction
• 6.35 mm Bore
• 15.875 mm OD
• High-Speed Capability
• Cross-Reference Support Available

📊 Specifications

Brand: MRC (SKF)

Model / Bearing Number: R4

Bearing Series: R-Series

Bearing Type: Single-Row Deep Groove Radial Ball Bearing

Dimension System: Inch / Imperial

Bore Diameter (d): 0.2500 in / 1/4 in / 6.350 mm

Outside Diameter (D): 0.6250 in / 5/8 in / 15.875 mm

Width (B): Approximately 0.1960 in / approximately 5.00 mm

Metric Equivalent: Approximately 6.35 × 15.875 × 5.00 mm

Rolling Elements: Ball

Number of Rows: 1

Raceway Type: Deep Groove

Basic Dynamic Load Rating (C): Approximately 332 lbf / 1,470 N

Basic Static Load Rating (C₀): Approximately 139 lbf / 618 N

Maximum Speed: Up to approximately 54,000 rpm, depending on execution, lubrication, closure type, fit, load, and temperature

Load Capability: Primarily radial load with light axial-load capability in both directions

Standard R4 Closure: Open, unless otherwise identified by suffix

Common Shielded Variants: R4FF / R4-ZZ – double metal shields

Common Sealed Variants: R4-2RS / R4-2RSR – double contact seals

Lubrication: Depends on whether the bearing is open, shielded, or sealed

Internal Clearance: Verify complete bearing specification

Precision: Suitable for miniature precision applications; exact tolerance class should be confirmed where critical

Temperature Range: Depends on lubricant, cage, seal material, fit, and operating environment

Shaft Fit: Nominal 1/4-inch shaft / 6.35 mm

Housing Fit: Nominal 5/8-inch housing bore / 15.875 mm

Installation Consideration: Confirm the exact suffix because some R4-family variants can have different OD or width dimensions

🔁 Equivalent

Suitable replacement or cross-reference candidate for compatible:

• MRC R4
• SKF R4
• R4 Inch-Series Ball Bearing
• 1/4 x 5/8 x 0.196 in Bearing
• 6.35x15.875x5 mm Ball Bearing
• Miniature Deep Groove Ball Bearing
• Instrument Ball Bearing
• RC Ball Bearing
• Small Motor Bearing
• Precision Inch-Series Bearing

Important suffix differences

Common R4-family variants may include:

• R4 – Open bearing
• R4FF / R4-ZZ – Double metal shields
• R4-2RS / R4-2RSR – Double rubber contact seals
• R4A / R4AZ – Special variants that may differ in outside diameter and/or width

For example, some R4A / R4AZ executions may use an OD around 0.7500 inch, which is larger than the standard R4 OD of 0.6250 inch.

Therefore, replacement should be based on the complete designation and actual dimensions, not only on the R4 family name.

(Always verify the original bearing OD, width, closure type, and suffix before ordering a replacement.)

📦 Availability

✅ In Stock

🚚 Fast Delivery Available

🌎 Worldwide Shipping Available

📦 MOQ: 1 Piece

🏭 Suitable for electronics, miniature motors, instruments, medical devices, RC systems, compact pumps, precision assemblies, small rollers, and machinery using a 1/4-inch shaft bearing.

📲 Contact via LINE ID: dusitrea

📧 Email: sales@seal4go.com

💬 Technical support available before ordering

🔍 Assistance available for cross-reference and equivalent part identification