MR105 Open-Type Miniature Deep Groove Ball Bearing For Electrical Instruments | 5×10×4 Mm
The MR105 is a Miniature Deep Groove Ball Bearing designed for high-precision applications in compact assemblies where minimal friction and smooth operation are essential. With an open design (no seals or shields), this bearing offers unobstructed performance, making it ideal for clean environments, high-speed mechanisms, and applications requiring frequent re-lubrication. Featuring a 5 mm bore and compact 10×4 mm dimensions, it delivers reliable radial and axial load support in tight spaces.
MR105 Deep Groove Ball Bearing 5x10x4 mm | Miniature Series | Open Design
This metric miniature bearing is built for low-torque, high-speed operation in precision instruments and small mechanical systems. Its open structure allows for easy maintenance and custom lubrication, while the deep groove geometry ensures stable performance under combined loads. Suitable for use in electrical instruments, small drives, and devices where accessibility and minimal friction are prioritized over sealing.

Perfect for precision mechanisms and compact assemblies that operate in clean, controlled environments:
Without seals or shields, the MR105 provides minimal rotational resistance, making it ideal for high-speed and low-torque applications. The open structure also allows for easy inspection, cleaning, and re-lubrication, extending service life in maintained systems.
With ultra-small dimensions of 5×10×4 mm and a lightweight design, this bearing saves critical space and reduces moving mass in precision assemblies. Its small cross-section is ideal where dimensional constraints are severe.
Manufactured to fine tolerances with polished raceways and precision-grade balls, the MR105 ensures quiet, smooth, and vibration-free rotation, essential for sensitive electrical and optical devices.
| Bearing Type | Single Row Deep Groove Ball Bearing |
| ISO Dimension Series | MR Series – Ultra-Miniature Series |
| Basic Designation | MR105 |
| Suffix | Open (No seal/shield) |
| Bore Diameter (d) | 5 mm |
| Outer Diameter (D) | 10 mm |
| Width (B) | 4 mm |
| Material (Races & Balls) | Chrome Steel (GCr15 / SAE 52100) |
| Precision Class | Standard / P5 Grade Available |
| Cage Material | Pressed Steel Ribbon |
| Dynamic Load Rating (Cʳ) | 1.35 kN |
| Static Load Rating (C₀ʳ) | 0.56 kN |
| Limiting Speed (Grease) | 30,000 r/min |
| Limiting Speed (Oil) | 38,000 r/min |
| Weight (approx.) | 2.5 g |
Direct replacement for:
The MR105 is supplied as an open bearing for maximum speed and accessibility. For applications requiring protection, shielded (MR105-ZZ) or sealed (MR105-2RS) variants are available upon request.
"The MR105 open-type bearing is the ideal choice for high-speed miniature applications in clean environments, where minimal friction and easy maintenance are key."
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Details
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