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The Ultimate Guide to Bearing Model Numbers
The bearing model number is a guide in identifying the bearing type, typical uses, durability and suitability. No matter what brand of bearing you buy, as long as you understand the meaning of the standard bearing model number, you can accurately identify the bearing you need. It’s worth noting that bearing model numbers are not universally standardized and may vary from brand to brand. As the top bearing manufacturer and supplier in China, we believe it is necessary to train non-technical personnel with bearing needs. Today we will discuss bearing numbers to identify bearings.
The series of numbers and words in a bearing model number may seem confusing, consisting of several paragraphs, each providing specific information about the bearing. Typically, a bearing model number consists of three distinct parts: prefix, base name, and suffix. The bearing model number indicates the specifications of the bearing, including bearing type, overall dimensions, running accuracy and internal clearance. This is true for the ABMA bearing codes as well as the codes used by Aubearing, which is similar to the numbering system used by many other manufacturers. Take NTN deep groove ball bearing code “TS2-6206 x1 LLB N C3 P5/2AS” as an example:
“TS2” stands for the prefix meaning “thermal stable up to 320°F (160°C)”;
“6206” is the basic code of the bearing – digital identification;
‘X1’, ‘LLB’, ‘C3’, ‘P5′, 2AS’ are suffixes.
Some bearings are identified only by a numerical code without any prefix or suffix, such as bearing “6203”.
Some bearings only have a suffix, such as “6203 LLB C3 P5”.
Bearing model number composition
The prefix mainly indicates a specific component of the bearing, but may also identify various bearing variants. Let’s take the NTN prefix as an example. In terms of thermal stability:
Prefix | Implication |
No Prefix | Heat stabilized up to 250°F (120°C) |
TS2 | Heat stabilized up to 320°F (160°C) |
TS3 | Heat stabilized up to 390°F (200°C) |
TS4 | Heat stabilized up to 480°F (250°C) |
5S | Ceramic rolling elements |
7MC3 | MEGAOHM® (ceramic coating) |
Prefix | Implication | |
No Symbol | High carbon chrome bearing steel (equivalent to AISI E52100) | |
F | Martensitic stainless steel (equivalent to AISI 440C) | |
N | Beryllium Copper | |
ICOS- | Oil sealed bearing unit | |
W | Stainless steel, metric dimensions | |
WBB1 | Stainless steel, metric dimensions, | |
Bearing first number identification
The starting number in the bearing model number is significant because it usually indicates the type of bearing. It helps determine the core design of the bearing. For example, in “6206”, the first number “6” means “single row deep groove ball bearing”. The table below lists the various types of bearings and their type codes.
Bearing Type | SKF | NSK | Timken | FAG |
Double row angular contact ball bearing | 0 | 3,5 |
| 3 |
Self-aligning ball bearing | 1 | 1 | 1,2 | 1 |
Spherical roller bearing, spherical roller thrust bearing | 2 | 2 | 2 | 2 |
Tapered roller bearing | 3 | 3 | 3 | 3 |
Double row deep groove ball bearing | 4 | 4 |
| 4 |
Thrust ball bearing | 5 | 5 | 5 | 5 |
Single row deep groove ball bearing | 6 | 6 | 6 | 6 |
Single row angular contact ball bearing | 7 | 7 | 7 | 7 |
Cylindrical roller thrust bearing | 8 |
| 8 |
Bearing second number
Series Code | Series Description |
0 | Extra Light |
1 | Extra Light Thrust |
2 | Light |
3 | Medium |
4 | Heavy |
8 | Extra Thin Section |
9 | Very Thin Section |
The second digit in the bearing model number usually indicates the bearing series. It reflects the sturdiness of the bearing, and its number indicates the light, medium or heavy series. Therefore, this number can give you insight into the bearing’s ability to handle different loads. For example, in “6 2 0 6”, the second number “2” means “very thin part”.
The third and fourth digits of the bearing number identification
The third and fourth digits in the bearing model number are important because they usually represent the bearing’s inner diameter (ID) in millimeters. They provide important information about the fit of the bearing to the shaft on which it is mounted.
The bore diameter in the bearing model number ranges from 0 to 3, representing 10 to 17 mm.
For numbers above “03”, the bore size is calculated as 5 times the value represented by the 3rd and 4th digits in the bearing model number.
For example, in “6206”, “0 6” corresponds to the bore diameter, therefore, “0 6” translates into a bearing bore diameter of 6*5=30mm.
If there is no fourth digit in the bearing model number, the third digit represents the bore diameter.
For example, for a bearing size “234”, the number “4” (equivalent to 4 mm) indicates the bore diameter.
*00 | 10 mm |
*01 | 12 mm |
*02 | 15 mm |
*03 | 17 mm |
*04 | 20 mm (4 x 5 mm) |
*05 | 25 mm (5 x 5 mm) |
*06 | 30 mm (6 x 5 mm) |
above | above => multiplication of 5mm |
* In case there is no fourth digit, then the 3rd digit indicates the bore size in mm. For example: in case of bearing 636, the bore size of the bearing will be 6mm | |
Suffix
Suffixes indicate different designs or variations that deviate from the original or current basic design. For example, shielded bearings and sealed bearings have different suffixes. For “6 2 0 6 LLB”, “LLB” stands for bearings with non-contact rubber seals.
Suffix | Description |
RS | with rubber seal on one side, one side open |
2 RS | with rubber seal on both sides |
Z | with a metal seal on one side, one side open |
2 Z / ZZ | with a metal seal on both sides |
V | One side Non-Contact Seal |
VV | Both Sides Non-Contact Seal |
DDU | Both sides Contact Seals |
Suffixes- Clearance | ||||||
Meaning | Normal radial internal clearance (RIC) | Radial internal clearance smaller than C2 | Radial internal clearance smaller than normal radial internal clearance greater than normal | Radial internal clearance greater than normal | Radial internal clearance greater than C3 | Radial internal clearance greater than C4 |
Code | C0/CN | C1 | C2 | C3 | C4 | C5 |
In addition to seals or guards, there are other suffixes such as cage design, materials, heat treatment, accuracy, clearance, preload, quiet operation, stability, lubrication, and other special specifications.
Conclusion
Identifying bearings by number requires understanding the bearing terminology and numbering system used by the manufacturer. Each bearing model number encodes specific information about the bearing type, size and design. Typically, this number includes a series code indicating the bearing type, a size series code indicating the bearing’s dimensional characteristics, and additional suffixes indicating specific design features such as seals, guards, or internal clearance. It is important to know whether the manufacturer follows the ABMA bearing code standards or uses a different standard. All manufacturers provide code keys on their websites or catalogs to help users interpret or specify the bearings required for their application. Regardless of which numbering system is used, each number and letter used in a bearing code has a specific meaning and helps identify the type and specification of the bearing. Many manufacturers or distributors offer bearing model number crossovers to facilitate interchange of bearings from one manufacturer to another. Due to the lack of interchange guidance for other bearing manufacturers, most suppliers will provide information for switching between their numbers and the ABMA standard.