Finding the correct ball bearing for your machinery can be a daunting task. With thousands of variations available, a reliable ball bearing size chart is an essential tool for engineers, maintenance professionals, and hobbyists. A small error in measurement can lead to premature failure, equipment damage, or costly downtime. In this guide, DUHUI will walk you through everything you need to know—from understanding what a ball bearing is, to accurately measuring dimensions, decoding bearing numbers, and finally, selecting the right bearing from our detailed size charts.
1. What is a Ball Bearing?
At its core, a ball bearing is a precision mechanical component designed to reduce rotational friction and support radial and axial loads. It acts as the interface between a rotating shaft and a stationary housing.
Core Components:
- Inner Ring: The part that fits onto the rotating shaft.
- Outer Ring: The part that fits into the stationary housing.
- Rolling Elements (Balls): The spherical components that facilitate smooth motion and carry the load.
- Cage (Retainer): A component that evenly spaces the balls, preventing them from contacting each other and reducing friction.
The primary functions of a ball bearing are to support the rotating shaft, carry loads (both radial and axial), minimize friction to improve energy efficiency, and maintain high rotational accuracy.
2. How to Measure and Decode Ball Bearing Sizes
Before you can consult a size chart, you need to know what you’re looking for. This involves both physical measurement and understanding the bearing’s identification code.
2.1 How to Measure the Three Critical Dimensions?
All standard ball bearings are defined by three key dimensions. Using a digital caliper is the most accurate way to measure these.
- Inner Diameter (ID): Also known as the bore. This is the diameter of the hole in the inner ring, which fits onto the shaft. Measure directly across the inside of the bearing.
- Outer Diameter (OD): The total diameter of the outer ring. Measure across the widest part of the bearing.
- Width (W): Also known as the thickness or height. Measure the overall thickness of the bearing from one side face to the other.
2.2 How to Read a Ball Bearing Number?
Most bearings have a standardized number printed on their seal or side. This number is not random; it follows an ISO system that encodes the bearing’s dimensions and type.
Case Study: Decoding the 6203 Bearing
Let’s take the widely used 6203 bearing as an example. Here’s how to break it down:
6: This is the type series, indicating it is a single-row deep groove ball bearing—the most common type.
2: This is the diameter series, representing the relationship between the bearing’s outer diameter and width. It helps define the load-carrying capacity.
03: This is the bore size code. For bearings with a bore diameter of 20mm or more, a simple formula applies: bore = code × 5. However, for codes 00, 01, 02, and 03, there are exceptions:
- 00 = 10mm
- 01 = 12mm
- 02 = 15mm
- 03 = 17mm
So, a 6203 bearing has a 17mm inner diameter.
Understanding Suffixes
The basic number is often followed by suffixes that provide critical details:
- ZZ or 2Z: Non-contact metal shields on one or both sides. They protect against large debris but allow high speeds.
- 2RS or 2RSH: Contact rubber seals on both sides. They provide excellent protection against dust and moisture but have a slightly higher friction torque.
- C3: Indicates a greater internal radial clearance than standard (CN). This is used in applications with high speeds or significant temperature differences.
2.3 International Standards
To ensure global interchangeability, bearings are manufactured according to standards set by organizations like the American Bearing Manufacturers Association (ABMA) and the International Organization for Standardization (ISO). A bearing from a manufacturer in Asia will have the same dimensions and tolerances as one from Europe or North America if they conform to these standards. This is why a 6203 bearing from DUHUI Bearing is dimensionally interchangeable with any other ISO-standard 6203.
3. Standard Ball Bearing Size Charts
Below are several ball bearing size charts to help you quickly identify the bearing you need. The first two tables offer quick reference for metric and inch series, while the subsequent detailed tables provide load ratings and other specifications for popular series.
3.1 Metric Series Quick Reference Chart
| Bearing Number | Inner Diameter (ID) (mm) | Outer Diameter (OD) (mm) | Width (W) (mm) |
| 6200 | 10 | 30 | 9 |
| 6201 | 12 | 32 | 10 |
| 6203 | 17 | 40 | 12 |
| 6004 | 20 | 42 | 12 |
| 6005 | 25 | 47 | 12 |
| 6300 | 10 | 35 | 11 |
3.2 Inch Series Quick Reference Chart
| Bearing Number | Inner Diameter (ID) (inches) | Outer Diameter (OD) (inches) | Width (W) (inches) |
| R2 | 0.125 | 0.375 | 0.140 |
| R4 | 0.250 | 0.625 | 0.196 |
| R6 | 0.375 | 0.875 | 0.281 |
| R8 | 0.500 | 1.125 | 0.312 |
| R10 | 0.625 | 1.375 | 0.312 |
3.3 Detailed Size Charts by Series (With Load Ratings)
For a more complete technical overview, the following tables include corner radius, weight, and dynamic/static load ratings. These are crucial for engineering and replacement decisions.
6000 Series (Light & Thin Section)
| Bearing Number | ID (mm) | OD (mm) | Width (mm) | Corner Radius (mm) | Weight (kg) | Dynamic Load (kN) | Static Load (kN) |
| 6000 | 10 | 26 | 8 | 0.3 | 0.019 | 5.6 | 2.36 |
| 6001 | 12 | 28 | 8 | 0.3 | 0.021 | 6.35 | 2.75 |
| 6002 | 15 | 32 | 9 | 0.3 | 0.03 | 7.28 | 3.1 |
| 6003 | 17 | 35 | 10 | 0.3 | 0.036 | 7.88 | 3.55 |
| 6004 | 20 | 42 | 12 | 0.6 | 0.072 | 9.35 | 4.3 |
| 6005 | 25 | 47 | 12 | 1.0 | 0.081 | 12.5 | 5.35 |
6200 Series (Light & Medium Duty)
| Bearing Number | ID (mm) | OD (mm) | Width (mm) | Corner Radius (mm) | Weight (kg) | Dynamic Load (kN) | Static Load (kN) |
| 6200 | 10 | 30 | 9 | 0.6 | 0.032 | 7.28 | 3.1 |
| 6201 | 12 | 32 | 10 | 0.6 | 0.037 | 7.88 | 3.55 |
| 6202 | 15 | 35 | 11 | 0.6 | 0.045 | 9.35 | 4.3 |
| 6203 | 17 | 40 | 12 | 0.6 | 0.065 | 10.2 | 5.05 |
| 6204 | 20 | 47 | 14 | 1.0 | 0.11 | 12.8 | 6.65 |
| 6205 | 25 | 52 | 15 | 1.0 | 0.15 | 14.3 | 7.4 |
6300 Series (Medium & Heavy Duty)
| Bearing Number | ID (mm) | OD (mm) | Width (mm) | Corner Radius (mm) | Weight (kg) | Dynamic Load (kN) | Static Load (kN) |
| 6300 | 10 | 35 | 11 | 0.6 | 0.053 | 9.57 | 4.2 |
| 6301 | 12 | 37 | 12 | 0.6 | 0.06 | 10.1 | 4.45 |
| 6302 | 15 | 42 | 13 | 1.0 | 0.082 | 12.5 | 5.35 |
| 6303 | 17 | 47 | 14 | 1.1 | 0.112 | 14.0 | 6.2 |
| 6304 | 20 | 52 | 15 | 1.1 | 0.142 | 15.3 | 7.55 |
| 6305 | 25 | 62 | 17 | 1.5 | 0.23 | 18.4 | 9.1 |
4. How to Choose the Right Ball Bearing for Your Application
Selecting the correct bearing involves more than just matching dimensions. Here are the key factors to consider based on your specific application:
Load Capacity: First, determine the direction and magnitude of the load. Deep groove ball bearings are designed for primarily radial loads but can handle some axial load. The size chart includes Dynamic Load (C) , which represents the load under which a bearing can operate for one million revolutions, and Static Load (C0) , which is the maximum load the bearing can withstand without permanent deformation.
Speed Rating: Bearings have maximum speed limits, influenced by their design, cage type, lubrication, and internal clearance. High-speed applications often require precision grades, lighter cages, and C3 clearance.
Material: Standard bearings are made from chrome steel (GCr15), which offers excellent hardness and fatigue life. For applications involving water, chemicals, or extreme temperatures, stainless steel (AISI 440C) bearings are preferred for their corrosion resistance.
Seals & Shields: The environment is a deciding factor.
- Open Bearings: Best for high-speed, clean environments where proper lubrication can be maintained.
- ZZ (Metal Shielded): Good for protecting against large particles without increasing friction.
- 2RS (Rubber Sealed): Ideal for dusty, moist, or contaminated environments, providing the best protection.
Internal Clearance: Most standard applications use normal (CN) clearance. If your application involves high operating temperatures (which cause the shaft to expand) or high speeds, a C3 (increased) clearance is recommended to prevent the bearing from seizing.
5. Frequently Asked Questions (FAQ)
Where can I find a bearing size chart and download a PDF?
You can find detailed size charts like the ones above on many manufacturers’ websites. For a printable version, you can often contact the manufacturer directly. At DUHUI Bearing, we provide technical datasheets for all our products upon request.
What issues arise from mismatched ball bearing sizes?
Using a bearing with an incorrect inner diameter (ID) can lead to spinning on the shaft, causing shaft damage. An incorrect outer diameter (OD) can cause the bearing to spin in its housing (fretting corrosion). In either case, the result is misalignment, excessive heat generation, vibration, and ultimately, premature bearing failure.
How to read bearing specifications if the number is worn off?
If the number is no longer visible, you must physically measure the bearing’s Inner Diameter (ID), Outer Diameter (OD), and Width (W) with a caliper. With these three dimensions, you can cross-reference them with a ball bearing size chart to identify the correct standard number.
What if a bearing makes abnormal noise?
Abnormal noise, such as grinding, squealing, or rattling, is often an early indicator of a problem. Common causes include contamination (dirt or metal particles), insufficient or improper lubrication, brinelling (damage from impact), or fatigue failure. It is crucial to inspect and replace the bearing promptly to avoid damage to the equipment.
What technical resources are available from DUHUI Bearings?
As a professional automotive wheel hub bearing manufacturer with extensive experience in other bearing types, DUHUI Bearing offers comprehensive technical support. Beyond standard size charts, we provide application-specific advice, material certifications, and custom engineering solutions to help you find the perfect bearing for your unique requirements.
