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When your assembly demands maximum radial load capacity in a minimal footprint, standard bearings fall short. Engineers, maintenance technicians, and DIY builders working on gearboxes, conveyor systems, and precision machinery need a bearing that fits tight bore housings without sacrificing strength. These needle roller bearings with inner ring are designed exactly for that challenge — delivering reliable performance where space is at a premium.
Each bearing consists of a needle roller and cage assembly combined with a machined inner ring, available across the NA4900–NA6920 series. The outer ring and rollers are manufactured from bearing-grade steel with a hardened raceway surface. Inner diameters range from 10 mm (0.39 in) to 100 mm (3.94 in), with outer diameters from 22 mm (0.87 in) to 140 mm (5.51 in) and widths from 13 mm (0.51 in) to 71 mm (2.80 in), covering a broad spectrum of shaft sizes.
Typical applications include automotive transmission shafts requiring needle roller bearing for gearbox repair, industrial conveyor roller bearing replacement in packaging lines, and precision machine tool spindle bearing upgrades where radial space is constrained. The inner ring design also allows the bearing to be mounted on unhardened or unground shafts — a practical advantage for field maintenance and retrofit installations.
| Bearing Series | NA4900–NA4920, NA6907–NA6920 |
|---|---|
| Type | Needle Roller Bearing with Inner Ring |
| Inner Diameter (Bore) | 10 mm – 100 mm (0.39 in – 3.94 in) |
| Outer Diameter | 22 mm – 140 mm (0.87 in – 5.51 in) |
| Width | 13 mm – 71 mm (0.51 in – 2.80 in) |
| Material | Bearing-grade steel (hardened raceway) |
| Cage Type | See variant options |
| Lubrication | See variant options |
| Load Direction | Radial |
| Dimensional Standard | ISO 355 / DIN 617 |
| Operating Temperature | See variant options |
| Quantity per Order | 1 piece |
Both series share the same bore and outer diameter for equivalent size numbers, but the NA69xx series has a wider width — for example, NA6914 (70×100×54 mm) vs NA4914 (70×100×30 mm). Choose NA69xx when you need higher radial load capacity and have sufficient axial space. Choose NA49xx for tighter axial clearances where a shorter bearing width is required.
Yes. The integrated inner ring is the key advantage of this bearing type. Because the inner ring provides its own hardened raceway, the shaft itself does not need to be hardened or precision-ground — unlike needle roller and cage assemblies without an inner ring. This makes them well-suited for field repairs and retrofit installations on standard turned shafts.
Needle roller bearings carry substantially higher radial loads than deep groove ball bearings of the same bore diameter, due to the larger number and greater length of rolling elements in contact with the raceway. However, they are not designed for axial (thrust) loads. If your application involves combined radial and axial loading, consider pairing with a thrust bearing or selecting a different bearing type.
These bearings are manufactured from standard bearing-grade steel, which provides good wear resistance but is not inherently corrosion-resistant. For wet, humid, or chemically exposed environments, ensure adequate sealing and re-lubrication intervals, or contact us to confirm availability of stainless steel or coated variants for your specific size.
Needle roller bearings with inner rings are typically lubricated with grease (NLGI 2 lithium-based) or oil, depending on operating speed and temperature. For moderate-speed applications, grease lubrication is standard. Re-lubrication intervals depend on load, speed, and environment — consult your equipment's maintenance schedule or contact us for application-specific guidance.
Each variant is labeled with its bearing designation and three key dimensions: bore (inner diameter) × outer diameter × width, all in millimeters. Measure your shaft diameter to determine the bore size, then confirm the outer diameter fits your housing bore. Cross-reference the designation (e.g., NA4908 = 40×62×22 mm) against your OEM part number or engineering drawing. If you are unsure, contact us with your shaft and housing dimensions.
In most cases, yes. These bearings are dimensioned to ISO 355 / DIN 617 standards, which are the basis for OEM needle roller bearing specifications across automotive transmissions, agricultural gearboxes, and industrial machinery. Match the bearing designation or the three key dimensions (bore × OD × width) to your OEM part to confirm interchangeability.
