If you've ever looked at a bearing part number, you know it can look like a confusing code of numbers and letters. But that code actually contains all the information you need to identify the bearing. Here's how to read and understand a standard bearing part number.
Most bearing part numbers follow a standard structure:
[Prefix] + [Bearing Type Code] + [Dimension Code] + [Internal Clearance/Modified Code] + [Suffix]
Let's break this down with an example: 6205-2RS
The first number indicates what type of bearing it is. Here are the most common codes:
| Code | Bearing Type |
|---|---|
| 6 | Deep Groove Ball Bearing |
| 1 | Self-Aligning Ball Bearing |
| N | Cylindrical Roller Bearing |
| 2 | Self-Aligning Roller Bearing (Spherical Roller) |
| 3 | Tapered Roller Bearing |
| 5 | Thrust Ball Bearing |
| 7 | Angular Contact Ball Bearing |
In our example "6205", the 6 means it's a deep groove ball bearing.
After the type code, the next digit (or two digits) is the dimension series, which indicates the overall size (diameter and width) relative to the bore size. Common dimension series are:
Extra light: 00 series
Light: 02, 03 series
Medium: 03, 04 series
Heavy: 04, 05 series
In our example "6205", the 2 indicates medium/light series (02 series).
The last one or two digits tell you the bore (inner diameter) of the bearing. For bores 10mm and above:
Multiply the number by 5 to get the bore diameter in millimeters
In our example "6205", the bore is 05 × 5 = 25mm.
Some common bore codes:
| Code | Bore Diameter (mm) |
|---|---|
| 00 | 10 |
| 01 | 12 |
| 02 | 15 |
| 03 | 17 |
| 04 | 20 |
| 05 | 25 |
| 06 | 30 |
| 07 | 35 |
| 08 | 40 |
Suffix letters after the main number describe special features like seals, clearance, cages, etc. Common suffixes:
| Suffix | Meaning |
|---|---|
| RS / 2RS | Rubber seal on one side / both sides |
| ZZ / 2Z | Metal shield on one side / both sides |
| C1, C2, C3 | Internal clearance: C1 smaller, C2 smaller, C3 larger than standard |
| A, B, C | Contact angle for angular contact bearings (A=15°, B=25°, C=40°) |
| TN | Polyamide/nylon cage |
| M | Brass cage |
So going back to our example: 6205-2RS = Deep groove ball bearing, 02 dimension series, 25mm bore, rubber seals on both sides.
The good news is that most major bearing manufacturers follow this same basic numbering system. This means a 6205-2RS from SKF, NSK, FAG, or MS Bearings all have the same dimensions and can be interchanged.
This interchangeability is what makes equivalent bearings possible – if you have the part number from the original brand, we can supply you with an identical equivalent.
If you have a bearing part number and need an equivalent replacement, MS Bearings can help. We supply equivalent bearings matching all major brands' part numbers, with identical dimensions and performance at 30-50% lower cost.
Just send us the part number from your old bearing, and we'll quickly quote you a price for a high-quality replacement. Contact us today.
