51220 bearing
100 × 150 mm · dynamic rating 119 kN · static rating 325 kN. Dimensions, load ratings, designation meaning, life estimates and equivalent parts.
51220 specification
| Designation | 51220 |
| Type | Single-direction thrust ball bearing |
| Series | 512 light-medium |
| Bore diameter d | 100 mm |
| Outside diameter D | 150 mm |
| Basic dynamic load rating C | 119 kN (119,000 N) |
| Basic static load rating C0 | 325 kN (325,000 N) |
| Ratio C0/C | 2.73 |
| Speed guide, grease lubrication | 2,400 rpm |
| Life exponent p | 3 (ball bearing) |
Values come from the Rotec AI bearing catalogue and are indicative. Confirm against the manufacturer's current catalogue before ordering. Not every dimension (such as width) is listed here.
What the designation 51220 means
| Code | Meaning |
|---|---|
| 512 | Single-direction thrust ball bearing, light-medium series (flat seat washers) |
| 20 | bore code "20" = 20 × 5 = 100 mm |
Basic rating life of the 51220
Basic rating life is L10 = (C / P)p million revolutions, where P is the equivalent dynamic load and p = 3 (ball bearing). For a 51220 with C = 119 kN, the table shows what that gives at different load levels. It is the ISO 281 basic life only: it does not include lubrication, contamination, misalignment or reliability modifiers.
| C / P | P as share of C | L10 (million rev) | L10 at 1,500 rpm | L10 at 3,000 rpm |
|---|---|---|---|---|
| 3 | 33.3% | 27 | 300 | 150 |
| 5 | 20.0% | 125 | 1,400 | 690 |
| 8 | 12.5% | 512 | 5,700 | 2,800 |
| 12 | 8.3% | 1,728 | 19,200 | 9,600 |
For example, a C / P of 5 means the equivalent load is 23.8 kN on this bearing. Use the Load Calculator to work out P for your actual radial and axial loads.
Equivalents of the 51220
Brand-by-brand equivalents for this exact designation are not shown here. The Cross-Reference tool accepts SKF, FAG, NSK, NTN, Timken, Koyo and NRB designations, and shows what is catalogued.
Where the 51220 is used
Thrust ball / thrust roller bearings are chosen for: Predominantly axial load. Typical equipment: Vertical pumps, extruders, turbines, marine and heavy gear drives. Thrust roller for higher axial capacity and shock.
Other sizes in the same series
The 51220 belongs to the “512 light-medium” series. The next size down, the 51218, has a bore of 90 mm and a dynamic rating of 112 kN. The next size up, the 51222, has a bore of 110 mm and a rating of 125 kN (+5%).
Common problems on bearings like the 51220
Most field failures trace back to lubrication, contamination, fits and alignment rather than the bearing itself. These guides explain how to recognise and prevent them:
Questions about the 51220
What are the dimensions of a 51220 bearing?
The 51220 has a bore of 100 mm and an outside diameter of 150 mm. It is a single-direction thrust ball bearing. Series: 512 light-medium.
What is the load rating of a 51220 bearing?
In the Rotec AI catalogue the 51220 has a basic dynamic load rating C of 119 kN and a basic static load rating C0 of 325 kN. Always confirm against the manufacturer's current catalogue.
What is the equivalent of a 51220 bearing?
Use the Cross-Reference tool in Rotec AI to check brand equivalents for the 51220.