How to read a deep groove ball bearing suffix code
A full order code packs six decisions into one line: what 6203-2RS/C3 P6 ZV4 says about series, bore, seals, clearance, precision and noise, and why suffix order differs.
One line, six decisions
A designation is a compressed specification. The basic number fixes boundary dimensions; the additions describe how the bearing is built for one application. The code 6203-2RS/C3 P6 ZV4 carries most of the decisions a buyer can make. It is a convention, not a universal standard: makers order and punctuate the elements differently.
Breaking down 6203-2RS/C3 P6 ZV4
| Part | What it states | In this example |
|---|---|---|
| 6203 | Series and bore | 62 series, 17 mm bore, 17 x 40 x 12 mm |
| -2RS | Closure type | Rubber seal on both sides |
| /C3 | Clearance group | Wider than the normal group |
| P6 | Precision grade | Tighter than P0, roughly ABEC-3 |
| ZV4 | Vibration and noise grade | Highest level of the ZV scale |
Separators are chosen by the maker: another catalogue may write 6203 2RS C3 P6 ZV4, or put precision before the seal. Read each segment as a decision, not a position.
Series and bore code
Series digits
The first digits give the diameter series: the outside diameter and width carried for a given bore. This catalogue uses series 60, 62, 63, 68 and 69. At 15 mm: 6202 (15 x 35 x 11 mm) and 6302 (15 x 42 x 13 mm); at 17 mm: 6003 (17 x 35 x 10 mm) and 6203 (17 x 40 x 12 mm). Series 68 and 69 are thin-section: 6800 is 10 x 19 x 5 mm and 6901 is 12 x 24 x 6 mm.
Bore digits
For bores of 10, 12, 15 and 17 mm the last two digits are the bore itself: 6200 is 10 mm, 6201 is 12 mm, 6202 is 15 mm, 6203 is 17 mm. From 20 mm the last two digits are multiplied by five, so 6004 is 20 mm. Miniature bearings use short numbers: 623 is 3 mm, 624 is 4 mm, 635 is 5 mm, 627 is 7 mm, 629 is 9 mm. A slash marks non-standard geometry, but the same designation can be used differently by different makers: 6203/8 is used both for a 12.7 mm (1/2 in) bore and for factory-specific custom bores, so always read the drawing. Our 6203/8 is produced with an 8 mm bore on the standard 6203 outside diameter, and 62001 is a 12 x 28 x 10 mm boundary size. Both are made to drawing, which controls.
Seals and shields: open, ZZ, 2RS, 2RZ
The closure suffix decides what reaches the raceway.
- Open: lowest friction and easy relubrication, but no protection.
- ZZ: steel shields with a small gap; low friction, blocks coarse dirt, not liquid-tight.
- 2RS: a rubber seal contacting the inner ring; the strongest protection against dust and moisture, at higher friction.
- 2RZ: a non-contacting rubber seal; most of the protection with less friction, but not water-tight.
All four forms are supplied; 2RS and 2RZ mean a seal on both sides, ZZ a shield.
Clearance: C0 to C5
Radial internal clearance is the radial movement between the rings of an unmounted bearing. C2 is smaller than the normal group, C3 is larger, then C4 and C5. The normal group is written C0 by many Chinese makers and CN in the ISO tables. Clearance is a fit and temperature decision, not a quality level: interference fits and a hot housing consume part of it. Catalogue models can be supplied in C0, C2, C3, C4 or C5; confirm the group per model. The radial clearance guide has the verified ranges and measurement method.
Precision: P0, P6, P5
Precision grades bound dimensional and running accuracy, including ring runout. P0 is the normal grade, P6 is tighter and P5 tighter again, roughly ABEC-1, ABEC-3 and ABEC-5. The ISO/GB and ABMA systems are not identical, so compare limit values rather than labels.
Noise and vibration: ZV1 to ZV4, EMQ and CM
Noise grades are vibration acceptance classes: the bearing runs under defined conditions and must stay below a limit. In Chinese motor-bearing practice the ZV numbers run from ZV1 upward, the higher number denoting a tighter requirement. Because scale, measured quantity and test conditions are set by the maker, a label alone does not allow comparison between suppliers.
EMQ means Electric Motor Quality; CM is a motor-bearing designation used by several makers. Both signal a bearing configured for electric-motor duty, but what each covers must be read from the maker's specification. The models listed here carry ZV1 to ZV4 and EMQ/CM options.
Why suffix order varies between manufacturers
Each company builds designations from its own conventions: the same closure may be 2RS at one maker and a different letter combination at another; clearance may be C0 or CN; precision may be P6 or an ABEC number; a noise class may be ZV4, Z4 or a maker-specific code.
Convert every code back into attributes before comparing quotations: two lines that look different may describe the same bearing, and two that look alike may differ in clearance, precision or grease. If a code is ambiguous, ask for the datasheet.
Checklist before you order
- Boundary dimensions, and whether the bore or width is non-standard.
- Closure, both sides or one.
- Radial clearance group.
- Precision grade.
- Noise grade, with the measurement method if critical.
- Cage material and grease.
- Marking and packaging.
- Quantity against MOQ, and the documents you need.
A quotation for "6203" alone is filled with the default configuration. Anything that affects your assembly belongs in the code or the order.
Sources
- GB/T 276-2013, boundary dimensions.
- GB/T 307.1, tolerance values for radial bearings.
- ISO 15:2017, boundary dimensions, general plan.