Needle roller bearings are widely used in automotive, industrial machinery, and aerospace applications due to their high load-carrying capacity in compact radial dimensions. A needle roller bearing size chart provides essential dimensional and performance data for selecting the correct bearing. DUHUI will present complete size charts for drawn cup, machined ring, thrust, and combined needle roller bearings, along with guidance on how to interpret the parameters. Whether you are an engineer, purchaser, or distributor, the following tables and explanations will help you identify the right bearing for your application.
What Is a Needle Roller Bearing?
A needle roller bearing is a rolling element bearing that uses long, thin cylindrical rollers with a length-to-diameter ratio of typically 3 to 10 or higher. The rollers are called “needles” because of their small diameter relative to their length. Needle roller bearings have a compact cross-section and can support high radial loads while requiring minimal radial space. They are often used without an inner ring, with the shaft surface serving as the raceway, or with a drawn cup or machined ring.
What Is a Needle Roller Bearing Size Chart?
A needle roller bearing size chart is a structured table that lists key specifications for a series of bearings. A typical chart includes the following parameters:
- Bearing designation – alphanumeric code identifying the model.
- Bore diameter (mm) – inner diameter, or shaft diameter if no inner ring.
- Outside diameter (mm) – outer ring diameter.
- Width (mm) – overall thickness or length of the bearing.
- Basic dynamic load rating C (kN) – load capacity for a rated life of one million revolutions.
- Basic static load rating C₀ (kN) – maximum static load without permanent deformation.
- Limiting speed (r/min) – maximum operational speed under ideal conditions.
- Reference speed (r/min) – thermal speed reference for standard lubrication.
- Weight (g) – approximate mass of the bearing.
Why Is the Needle Roller Bearing Size Chart Important?
The size chart is a critical tool for multiple stakeholders:
- For engineers – it enables precise selection based on load, speed, space constraints, and life requirements.
- For purchasers and distributors – it ensures correct ordering, cross-referencing, and inventory management.
- For maintenance teams – it aids in identifying replacement bearings from existing equipment markings.
Using an accurate size chart prevents mismatches that could lead to premature failure, excessive friction, or unsafe operation.
Types of Needle Roller Bearings and Selection Guide
The following table helps you choose the appropriate needle roller bearing type based on your application requirements.
| If you need… | Choose this type |
|---|---|
| Very compact radial bearing | Drawn cup (HK open end / BK closed end) |
| Higher rigidity / heavier radial loads | Machined ring (NK/RNA without inner ring, NA with inner ring) |
| Axial load only | Thrust needle roller (AXK + washers) |
| Radial + axial loads in one unit | Combined (NKX standard / NKXR compact / NKIA heavy duty) |
| Ultra-compact, shaft & housing as raceways | Needle roller & cage assembly (K series) |
Needle Roller Bearing Size Charts by Type
Drawn Cup Needle Roller Bearing Size Chart
Open ends (HK series)
| Bearing No. | Bore Diameter (mm) | Outside Diameter (mm) | Width (mm) | Basic Dynamic Load Rating C (kN) | Basic Static Load Rating C₀ (kN) | Limiting Speed (r/min) | Reference Speed (r/min) | Weight (g) |
|---|---|---|---|---|---|---|---|---|
| HK 0306 | 3 | 6 | 6 | 0.98 | 1.20 | 45 000 | 30 000 | 2 |
| HK 0408 | 4 | 8 | 8 | 1.76 | 2.10 | 40 000 | 28 000 | 4 |
| HK 0509 | 5 | 9 | 9 | 1.30 | 1.60 | 38 000 | 26 000 | 6 |
| HK 0608 | 6 | 10 | 8 | 1.90 | 2.40 | 36 000 | 25 000 | 8 |
| HK 0610 | 6 | 10 | 10 | 2.40 | 3.10 | 34 000 | 24 000 | 10 |
| HK 0810 | 8 | 12 | 10 | 3.69 | 4.60 | 22 000 | 15 000 | 15 |
| HK 1012 | 10 | 14 | 12 | 5.39 | 6.30 | 20 000 | 14 000 | 22 |
| HK 1516 | 15 | 19 | 16 | 8.80 | 14.00 | 20 000 | 14 000 | 45 |
| HK 2016 | 20 | 26 | 16 | 12.30 | 25.00 | 14 000 | 9 500 | 75 |
| HK 2516 | 25 | 32 | 16 | 15.00 | 33.00 | 11 000 | 7 500 | 110 |
| HK 3016 | 30 | 37 | 16 | 18.00 | 40.00 | 9 500 | 6 500 | 150 |
| HK 4016 | 40 | 47 | 16 | 23.00 | 55.00 | 7 000 | 4 800 | 220 |
| HK 5016 | 50 | 58 | 16 | 27.00 | 65.00 | 6 000 | 4 000 | 320 |
| HK 6020 | 60 | 68 | 20 | 31.90 | 80.00 | 4 800 | 3 200 | 480 |
Closed ends (BK series)
| Bearing No. | Bore Diameter (mm) | Outside Diameter (mm) | Width (mm) | Basic Dynamic Load Rating C (kN) | Basic Static Load Rating C₀ (kN) | Limiting Speed (r/min) | Reference Speed (r/min) | Weight (g) |
|---|---|---|---|---|---|---|---|---|
| BK 0306 | 3 | 6 | 6 | 0.95 | 1.15 | 42 000 | 28 000 | 3 |
| BK 0408 | 4 | 8 | 8 | 1.70 | 2.00 | 38 000 | 26 000 | 5 |
| BK 0509 | 5 | 9 | 9 | 1.25 | 1.55 | 36 000 | 25 000 | 7 |
| BK 0608 | 6 | 10 | 8 | 1.85 | 2.30 | 34 000 | 24 000 | 9 |
| BK 0610 | 6 | 10 | 10 | 2.30 | 3.00 | 32 000 | 22 000 | 12 |
| BK 0810 | 8 | 12 | 10 | 3.60 | 4.40 | 21 000 | 14 000 | 18 |
| BK 1012 | 10 | 14 | 12 | 5.30 | 6.20 | 19 000 | 13 000 | 26 |
| BK 1516 | 15 | 19 | 16 | 8.50 | 13.50 | 18 000 | 12 000 | 50 |
| BK 2016 | 20 | 26 | 16 | 11.80 | 23.00 | 13 000 | 9 000 | 85 |
| BK 2516 | 25 | 32 | 16 | 14.50 | 30.00 | 10 000 | 7 000 | 120 |
| BK 3016 | 30 | 37 | 16 | 17.00 | 38.00 | 9 000 | 6 000 | 165 |
| BK 4016 | 40 | 47 | 16 | 21.50 | 52.00 | 6 500 | 4 500 | 240 |
| BK 5016 | 50 | 58 | 16 | 25.00 | 62.00 | 5 500 | 3 800 | 340 |
| BK 6020 | 60 | 68 | 20 | 30.00 | 75.00 | 4 500 | 3 000 | 520 |
Machined Ring Needle Roller Bearing Size Chart
With inner ring (NA series)
| Bearing No. | Bore Diameter (mm) | Outside Diameter (mm) | Width (mm) | Basic Dynamic Load Rating C (kN) | Basic Static Load Rating C₀ (kN) | Reference Speed (r/min) | Limiting Speed (r/min) | Weight (g) |
|---|---|---|---|---|---|---|---|---|
| NA 20/16 | 20 | 28 | 16 | 18.0 | 28.0 | 9 500 | 14 000 | 45 |
| NA 25/20 | 25 | 33 | 20 | 25.0 | 40.0 | 8 000 | 12 000 | 75 |
| NA 30/20 | 30 | 40 | 20 | 33.0 | 55.0 | 7 000 | 10 000 | 120 |
| NA 35/25 | 35 | 45 | 25 | 41.0 | 70.0 | 6 000 | 9 000 | 180 |
| NA 40/25 | 40 | 52 | 25 | 52.0 | 90.0 | 5 500 | 8 000 | 260 |
| NA 45/25 | 45 | 58 | 25 | 62.0 | 110.0 | 5 000 | 7 500 | 340 |
| NA 50/30 | 50 | 65 | 30 | 75.0 | 140.0 | 4 500 | 7 000 | 480 |
Without inner ring (NK / RNA series)
| Bearing No. | Bore Diameter (mm) | Outside Diameter (mm) | Width (mm) | Basic Dynamic Load Rating C (kN) | Basic Static Load Rating C₀ (kN) | Reference Speed (r/min) | Limiting Speed (r/min) | Weight (g) |
|---|---|---|---|---|---|---|---|---|
| NK 20/16 | 20 | 28 | 16 | 18.0 | 28.0 | 9 500 | 14 000 | 35 |
| NK 25/20 | 25 | 33 | 20 | 25.0 | 40.0 | 8 000 | 12 000 | 60 |
| NK 30/20 | 30 | 40 | 20 | 33.0 | 55.0 | 7 000 | 10 000 | 95 |
| NK 35/25 | 35 | 45 | 25 | 41.0 | 70.0 | 6 000 | 9 000 | 150 |
| NK 40/25 | 40 | 52 | 25 | 52.0 | 90.0 | 5 500 | 8 000 | 220 |
| RNA 20/16 | 20 | 28 | 16 | 18.0 | 28.0 | 9 500 | 14 000 | 32 |
| RNA 25/20 | 25 | 33 | 20 | 25.0 | 40.0 | 8 000 | 12 000 | 55 |
| RNA 30/20 | 30 | 40 | 20 | 33.0 | 55.0 | 7 000 | 10 000 | 90 |
Needle Roller Thrust Bearing Size Chart
AXK series with AS washers
| Bearing No. | Washer Model | Bore Diameter d (mm) | Outside Diameter D (mm) | Roller Diameter Dw (mm) | Width B (mm) | Basic Dynamic Load Rating C (kN) | Basic Static Load Rating C₀ (kN) | Limiting Speed (r/min) |
|---|---|---|---|---|---|---|---|---|
| AXK0414 | AS0414 | 4 | 14 | 2 | 1 | 3.52 | 6.4 | 16800 |
| AXK0515 | AS0515 | 5 | 15 | 2 | 1 | 3.8 | 7.36 | 16800 |
| AXK0619 | AS0619 | 6 | 19 | 2 | 1 | 5.44 | 12.4 | 15200 |
| AXK0821 | AS0821 | 8 | 21 | 2 | 1 | 6.24 | 15.52 | 14400 |
| AXK1024 | AS1024 | 10 | 24 | 2 | 1 | 7.36 | 20.4 | 13600 |
| AXK1226 | AS1226 | 12 | 26 | 2 | 1 | 7.92 | 23.2 | 12000 |
| AXK1528 | AS1528 | 15 | 28 | 2 | 1 | 9.04 | 28.8 | 10400 |
| AXK1730 | AS1730 | 17 | 30 | 2 | 1 | 9.52 | 31.6 | 9600 |
| AXK2035 | AS2035 | 20 | 35 | 2 | 1 | 10.48 | 37.2 | 8000 |
| AXK2542 | AS2542 | 25 | 42 | 2 | 1 | 11.76 | 46.4 | 6800 |
| AXK3047 | AS3047 | 30 | 47 | 2 | 1 | 13.04 | 56 | 6000 |
| AXK3552 | AS3552 | 35 | 52 | 2 | 1 | 14.24 | 64.8 | 5200 |
| AXK4060 | AS4060 | 40 | 60 | 3 | 1 | 22.4 | 91.2 | 4800 |
| AXK4565 | AS4565 | 45 | 65 | 3 | 1 | 24 | 102.4 | 4000 |
| AXK5070 | AS5070 | 50 | 70 | 3 | 1 | 25.6 | 114.4 | 3840 |
| AXK5578 | AS5578 | 55 | 78 | 3 | 1 | 30.4 | 148.8 | 3440 |
| AXK6085 | AS6085 | 60 | 85 | 3 | 1 | 35.6 | 187.2 | 3200 |
| AXK6590 | AS6590 | 65 | 90 | 3 | 1 | 37.2 | 204 | 2960 |
| AXK7095 | AS7095 | 70 | 95 | 4 | 1 | 43.2 | 204 | 2800 |
| AXK75100 | AS75100 | 75 | 100 | 4 | 1 | 44 | 212 | 2640 |
| AXK80105 | AS80105 | 80 | 105 | 4 | 1 | 44.8 | 224 | 2480 |
| AXK85110 | AS85110 | 85 | 110 | 4 | 1 | 46.4 | 232 | 2400 |
| AXK90120 | AS90120 | 90 | 120 | 4 | 1 | 58.4 | 324 | 2160 |
| AXK100135 | AS100135 | 100 | 135 | 4 | 1 | 72.8 | 448 | 2000 |
| AXK110145 | AS110145 | 110 | 145 | 4 | 1 | 77.6 | 496 | 1840 |
| AXK120155 | AS120155 | 120 | 155 | 4 | 1 | 81.6 | 544 | 1680 |
| AXK130170 | AS130170 | 130 | 170 | 5 | 1 | 106.4 | 672 | 1520 |
| AXK140180 | AS140180 | 140 | 180 | 5 | 1 | 110.4 | 720 | 1440 |
| AXK150190 | AS150190 | 150 | 190 | 5 | 1 | 114.4 | 768 | 1360 |
| AXK160200 | AS160200 | 160 | 200 | 5 | 1 | 118.4 | 816 | 1280 |
Combined Needle Roller Bearings Size Chart
Standard design (NKX series – radial + thrust)
| Bearing No. | Bore Diameter (mm) | Outside Diameter (mm) | Width (mm) | Basic Dynamic Load Rating C (kN) | Basic Static Load Rating C₀ (kN) | Reference Speed (r/min) | Limiting Speed (r/min) | Weight (g) |
|---|---|---|---|---|---|---|---|---|
| NKX 10 | 10 | 19 | 30 | 6.5 | 11.2 | 10000 | 14000 | 55 |
| NKX 12 | 12 | 21 | 30 | 7.8 | 13.5 | 9500 | 13000 | 70 |
| NKX 15 | 15 | 24 | 30 | 10.5 | 18 | 8500 | 12000 | 95 |
| NKX 17 | 17 | 26 | 32 | 12.8 | 22 | 8000 | 11000 | 120 |
| NKX 20 | 20 | 30 | 32 | 17.5 | 32 | 6000 | 8000 | 180 |
| NKX 25 | 25 | 35 | 32 | 23 | 42 | 5000 | 7000 | 260 |
| NKX 30 | 30 | 40 | 35 | 32 | 60 | 4500 | 6500 | 320 |
| NKX 35 | 35 | 45 | 35 | 38 | 72 | 4000 | 6000 | 410 |
| NKX 40 | 40 | 52 | 40 | 48 | 95 | 3500 | 5500 | 520 |
| NKX 45 | 45 | 58 | 40 | 58 | 120 | 3000 | 5000 | 650 |
| NKX 50 | 50 | 65 | 45 | 70 | 150 | 2800 | 4500 | 820 |
| NKX 55 | 55 | 72 | 45 | 82 | 180 | 2600 | 4200 | 980 |
| NKX 60 | 60 | 78 | 50 | 95 | 210 | 2400 | 4000 | 1200 |
| NKX 65 | 65 | 85 | 50 | 108 | 240 | 2200 | 3800 | 1450 |
| NKX 70 | 70 | 90 | 55 | 122 | 270 | 2000 | 3500 | 1700 |
| NKX 75 | 75 | 95 | 55 | 136 | 300 | 1900 | 3300 | 1950 |
| NKX 80 | 80 | 100 | 60 | 150 | 330 | 1800 | 3200 | 2200 |
| NKX 85 | 85 | 110 | 60 | 168 | 370 | 1700 | 3000 | 2500 |
| NKX 90 | 90 | 120 | 65 | 190 | 420 | 1600 | 2800 | 2850 |
| NKX 100 | 100 | 135 | 70 | 225 | 500 | 1500 | 2600 | 3400 |
Compact design (NKXR series)
| Bearing No. | Bore Diameter (mm) | Outside Diameter (mm) | Width (mm) | Basic Dynamic Load Rating C (kN) | Basic Static Load Rating C₀ (kN) | Reference Speed (r/min) | Limiting Speed (r/min) | Weight (g) |
|---|---|---|---|---|---|---|---|---|
| NKXR 10 | 10 | 19 | 23 | 6 | 10 | 10000 | 14000 | 45 |
| NKXR 12 | 12 | 21 | 25 | 7.2 | 12 | 9500 | 13000 | 58 |
| NKXR 15 | 15 | 24 | 26 | 9.5 | 16.5 | 8500 | 12000 | 75 |
| NKXR 17 | 17 | 26 | 28 | 11 | 19 | 8000 | 11000 | 95 |
| NKXR 20 | 20 | 30 | 28 | 15 | 28 | 6000 | 8000 | 135 |
| NKXR 25 | 25 | 35 | 30 | 20 | 36 | 5000 | 7000 | 190 |
| NKXR 30 | 30 | 40 | 32 | 28 | 52 | 4500 | 6500 | 245 |
| NKXR 35 | 35 | 45 | 34 | 34 | 65 | 4000 | 6000 | 315 |
| NKXR 40 | 40 | 52 | 36 | 42 | 85 | 3500 | 5500 | 410 |
| NKXR 50 | 50 | 65 | 40 | 60 | 135 | 2800 | 4500 | 650 |
Heavy duty (NKIA series)
| Bearing No. | Bore Diameter (mm) | Outside Diameter (mm) | Width (mm) | Basic Dynamic Load Rating C (kN) | Basic Static Load Rating C₀ (kN) | Reference Speed (r/min) | Limiting Speed (r/min) | Weight (g) |
|---|---|---|---|---|---|---|---|---|
| NKIA 10 | 10 | 26 | 32 | 9.5 | 18 | 9000 | 12000 | 110 |
| NKIA 12 | 12 | 28 | 34 | 11.5 | 22 | 8500 | 11000 | 135 |
| NKIA 15 | 15 | 32 | 36 | 15 | 28 | 8000 | 10000 | 180 |
| NKIA 17 | 17 | 35 | 38 | 18 | 35 | 7500 | 9500 | 220 |
| NKIA 20 | 20 | 42 | 40 | 24 | 48 | 6500 | 8500 | 300 |
| NKIA 25 | 25 | 47 | 45 | 32 | 65 | 5500 | 7500 | 420 |
| NKIA 30 | 30 | 52 | 50 | 42 | 85 | 4800 | 6800 | 560 |
| NKIA 35 | 35 | 62 | 55 | 55 | 115 | 4200 | 6000 | 740 |
| NKIA 40 | 40 | 68 | 60 | 68 | 145 | 3800 | 5500 | 920 |
| NKIA 50 | 50 | 80 | 70 | 95 | 210 | 3200 | 4800 | 1450 |
Frequently Asked Questions (FAQs)
How can I download a needle roller bearing size chart in PDF?
Most bearing manufacturers provide PDF catalogs on their official websites. You can visit the technical resources or download section of a manufacturer like DUHUI Bearing to obtain a complete size chart in PDF format. Alternatively, search for “needle roller bearing size chart PDF” on reliable industrial platforms.
How can I get a needle roller bearing size chart for SKF?
SKF publishes detailed product tables in its online interactive catalog and PDF documents. Access the SKF website, navigate to “Products” > “Roller bearings” > “Needle roller bearings”, and use their size chart filter or download the relevant section. Cross-referencing with generic charts is possible, but always verify with the original SKF data.
How to select a needle roller bearing from the size chart?
Start by determining the required bore diameter (shaft size) and outside diameter (housing bore). Then check the width to fit the available space. Compare the dynamic load rating C with the application’s equivalent dynamic load to estimate bearing life. Also ensure the limiting speed meets or exceeds the operating speed. For combined loads, refer to combined bearing tables.
What is the difference between open-end and closed-end drawn cup bearings?
Open-end drawn cup bearings (HK series) have both ends open, allowing through-shaft or lubrication flow. Closed-end (BK series) have one end closed, which protects the bearing from contaminants and retains lubricant on one side. Closed-end types are often used at shaft ends.
When should I use a needle roller bearing with inner ring vs without?
Use a bearing with an inner ring (NA series) when the shaft surface is not hardened, ground, or suitable as a raceway. Without inner ring (NK or RNA series) requires the shaft to be heat-treated and precision-ground to function as the inner raceway, which saves radial space and reduces cost when the shaft can be properly manufactured.
What do C and C₀ ratings mean in the size chart?
C (basic dynamic load rating) represents the constant radial load under which a group of identical bearings will achieve a rated life of one million revolutions. C₀ (basic static load rating) is the maximum static radial load that can be applied without causing permanent deformation exceeding 0.0001 times the roller diameter. Higher values indicate greater load capacity.
How to calculate the required bearing size based on load and speed?
First calculate the equivalent dynamic load P from radial and axial forces. Then use the life equation L10 = (C/P)^3 for roller bearings (where L10 is in million revolutions). Adjust for required life hours and operating speed. The selected bearing’s limiting speed must also be above the maximum shaft speed. Online calculators and manufacturer software can assist.
Are needle roller bearing size charts standardized across manufacturers?
Basic dimensions (bore, OD, width) follow ISO standards for most series, so bearings from different manufacturers are often interchangeable. However, load ratings, speed limits, and internal design may vary. Always refer to the specific manufacturer’s size chart for accurate performance data. Cross-referencing is common but should be validated.
What is the tolerance class for needle roller bearings?
Standard needle roller bearings are manufactured to normal tolerance class (PN) according to ISO 492. For higher precision applications, classes P6, P5, or P4 may be available. The size chart typically indicates the tolerance class; if not specified, it is assumed normal class. Shaft and housing tolerances must match the bearing type (e.g., g6 or h6 for shafts without inner ring).
How to mount a needle roller bearing correctly?
For drawn cup bearings, press the bearing into a rigid housing using an installation tool that applies force only to the outer ring. For machined ring bearings, use an arbor press on the ring that is press-fitted (usually the outer ring for radial bearings). Never apply force through the rollers. Ensure the shaft or housing has proper fillet radii and surface hardness (≥58 HRC) when no inner ring is used.
Can needle roller bearings accommodate axial loads?
Standard radial needle roller bearings (drawn cup or machined ring without thrust features) are not designed for significant axial loads. For combined radial and axial loads, use combined needle roller bearings (NKX, NKXR, NKIA series) or separate thrust bearings (AXK). Thrust needle roller bearings handle pure axial loads only.
Conclusion
The needle roller bearing size chart is an indispensable reference for selecting the correct bearing based on dimensional, load, and speed requirements. This article has provided comprehensive size tables for drawn cup, machined ring, thrust, and combined types, along with a selection guide and answers to common technical questions. For specific applications or custom requirements, consulting a bearing manufacturer such as DUHUI Bearing ensures access to accurate product data, PDF catalogs, and engineering support. Always use the latest official size charts when making procurement or design decisions.
