Bearing speed and lubrication — how to use the three limit-speed columns
2026-10-29
The two grease columns and one oil column, their measured range across 100 models, how much speed a contact seal costs, and the 26 models with no RS/2RS grease figure.
Three columns in our parameter table relate to speed, split across two lubrication modes and four value groups. This page explains how they divide, where our catalogue actually falls, how much speed a contact seal costs, and which 26 models have a blank in that column — blank means blank.
Three numbers, not two
Grease, open / Z / ZZ / RZ / 2RZ — one group
This is the first column: limit speed, grease, open/Z/ZZ/RZ/2RZ. Every form without a rubber seal takes this column — open, metal shields (Z / ZZ) and non-contact rubber (RZ / 2RZ) are all included.
Grease, RS / 2RS — a separate group
The second column is reserved for contact rubber seals: limit speed, grease, RS/2RS.
Why split them? A contact seal lip runs against the mating surface, generating continuous friction and heat. The same model in 2RS therefore has a noticeably lower grease speed limit (see below).
Oil — its own column
The third column, limit speed, oil, is not split by seal type. Oil dissipates heat better than grease, so the oil figure for a given model is normally higher than the grease figure.
The actual range in the table
Where the 100 models fall
| Value group | Rows with a value | Minimum | Median | Maximum |
|---|---|---|---|---|
| Grease, open/Z/ZZ/RZ/2RZ | 500 / 700 | 5,300 | 17,500 | 46,000 |
| Grease, RS/2RS | 148 / 700 | 3,600 | 10,000 | 24,000 |
| Oil | 400 / 700 | 6,300 | 20,000 | 53,000 |
All in r/min. Row counts below 700 are expected: the first column only applies to 500 rows (5 non-contact forms × 100 models), the second only to 200 rows (RS/2RS × 100), and the oil column is not filled on every row.
Is oil always higher than grease
Across the 300 pairs where the same model has values in both columns: oil is higher in all 300, never equal and never lower.
The multiplier is tight: minimum 1.11, median 1.19, maximum 1.27 — oil is roughly 11–27% higher, not double.
How much speed a 2RS costs
Among the 74 models that have values in both the grease open group and the RS/2RS group, the RS group equals 54%–80% of the open group, median 67%.
Some concrete cases:
| Model | Open group (grease) | RS/2RS group (grease) | Retained |
|---|---|---|---|
| 6807 | 14,000 | 7,500 | 54% |
| 6809 | 11,000 | 6,000 | 55% |
| 6300 | 22,000 | 17,000 | 77% |
| 6301 | 20,000 | 16,000 | 80% |
So "just take 2RS, it is simpler" has a price, and this is where it shows: the speed ceiling drops by three to four tenths. Load capacity is unaffected (see load ratings); only speed is constrained.
Three numbers side by side for common models:
| Model | Grease (open group) | Grease (RS/2RS) | Oil |
|---|---|---|---|
| 6000 | 30,000 | 22,000 | 36,000 |
| 6205 | 13,000 | 9,000 | 15,000 |
| 6305 | 11,000 | 8,000 | 13,000 |
26 models have no RS/2RS grease figure
Which models
Of the 200 RS/2RS rows, 52 have no value in that column = 26 base models × 2 (one RS row and one 2RS row each):
- 605, 606, 607
- 625, 626, 635
- 685, 686, 687, 688, 689
- 695, 696, 697, 698, 699
- 16001 through 16010 (ten consecutive models)
Why it is blank
The parameter table simply has no value there. The reason may be that these small contact-seal variants were never measured or never supplied — but the table does not state a reason, and we do not invent one.
What it means in practice: if you select RS / 2RS for these models, this site does not publish a grease limit speed for that form. The open-group and oil figures are still recorded and can be looked up as usual.
How to use
Pick the column that matches your setup
- Decide the lubrication mode first: grease or oil.
- Then decide whether you have contact seals: with RS/2RS you can only use the second column.
- Compare the figure against your operating speed. Operating speed should stay below the limit with margin — how much margin depends on the application and heat dissipation, and the table does not provide that factor.
- If the second column is blank (the 26 models above), do not reuse the open-group number for an RS part.
What they cannot tell you
- Not your permitted operating speed: these are limits; running continuously near them shortens grease life substantially.
- No temperature rise or cooling conditions: ambient temperature, airflow and mounting all change the usable speed, and none are in the table.
- No grease brand or fill amount: the table only distinguishes grease from oil, with no brand, grade or fill ratio.
- No relubrication interval: that field does not exist.
If you need a judgement against real conditions, send us the speed, temperature and lubrication mode (contact us). Fields the table does not contain are not filled with numbers here.
The largest drop and a complete pairing: 6807 (14,000 → 7,500 r/min, 54% retained) and 6205 (13,000 → 9,000 r/min).