Bearing suffix codes — Open, Z, ZZ, RZ, 2RZ, RS, 2RS
2026-10-12
Which fields really change when you switch a deep groove ball bearing seal suffix, and which stay identical, using only the values recorded in our factory specification table.
Every one of our 100 base models is listed with 7 seal variants, so the catalogue holds 700 published specifications. This page explains what actually changes when you move from one suffix to another — and it stays strictly inside what our factory specification table records.
Two families — with and without a rubber seal
How many seal options does one base model have?
Seven. The seal form column in our specification table takes exactly these values: `Open`, `Z`, `ZZ`, `RZ`, `2RZ`, `RS` and `2RS`. All 100 base models carry all seven; none carries fewer. The open bearing is recorded as 开式 in that column.
Which suffixes have a rubber seal?
Four of them — `RZ`, `2RZ`, `RS` and `2RS`. On those rows the seal material column reads NBR nitrile rubber (丁腈橡胶NBR). The other three (`Open`, `Z`, `ZZ`) have no seal material recorded at all; no elastomer part is fitted.
We stop there on purpose. The table states whether an elastomer seal is present and what it is made of. It does not grade sealing performance, so we do not grade it either.
What changes and what does not
Does the seal change the dimensions?
Bore `d`, outside diameter `D`, chamfer `r`, shoulder limits `da` and `ra`, and the weight are identical across all seven variants for 95 of the 100 base models.
The exceptions are five models in the 6800 series — 685, 686, 687, 688 and 689 — where width `B` and weight differ between the open bearing and the sealed ones:
| Model | Width, Open | Width, Z / ZZ / RZ / 2RZ / RS / 2RS |
|---|---|---|
| 685 | 3 mm | 5 mm |
| 686 | 3.5 mm | 5 mm |
| 687 | 3.5 mm | 5 mm |
| 688 | 4 mm | 5 mm |
| 689 | 4 mm | 5 mm |
If your housing was machined around an open bearing, check those five before ordering a sealed one.
Does the seal change the load rating?
No. Dynamic load rating `Cr` and static load rating `Cor` are identical across all seven variants for all 100 base models. A 6205 is rated Cr 14.0 kN / Cor 7.9 kN whether you take it open or as 2RS.
Speed limit and lubrication
Does the seal change the limiting speed?
Yes — this is the field most often overlooked. For 74 of the 100 base models the grease limiting speed takes two or more different listed values across the seven variants. Taking 6205 as the worked example:
| Suffix | Grease limiting speed | Oil limiting speed | Lubrication column |
|---|---|---|---|
| Open | 13000 r/min | 15000 r/min | grease / oil |
| Z | 13000 r/min | 15000 r/min | grease / oil |
| ZZ | 13000 r/min | not listed | grease |
| RZ | 13000 r/min | 15000 r/min | grease / oil |
| 2RZ | 13000 r/min | not listed | grease |
| RS | 9000 r/min | 15000 r/min | grease / oil |
| 2RS | 9000 r/min | not listed | grease |
Two structural facts hold across the whole catalogue, not just for 6205:
- `ZZ`, `2RZ` and `2RS` are recorded as grease lubrication only — none of their 100 rows carries an oil limiting speed.
- `Open`, `Z`, `RZ` and `RS` are recorded as grease / oil.
Why do some rows have no speed value?
Because the value genuinely is not in the table, and a printed gap is more useful to you than a printed guess. Contact seals are the main case: for 26 of the 100 base models — including 685 to 689, 695 to 699 and the full 16001 to 16010 run — the `RS` and `2RS` rows carry no grease limiting speed. If you need a sealed small-bore bearing at a known speed, ask us about that specific model instead of assuming a figure.
What this page does not tell you
Which fields are missing from the table?
The specification table records geometry, load ratings, speeds, seal form, seal material, ring material, cage, precision and clearance. It does not record ingress protection ratings, allowable temperature range, frictional torque, grease fill or service-life calculations. We do not publish numbers we cannot source, so send us the application and we will confirm against the actual part. Minimum order quantity is 500 pcs and standard lead time is 2 days, shipped worldwide.
Related reading: ring material and cage and precision and clearance.