51311 bearing
55 × 105 mm · dynamic rating 101 kN · static rating 224 kN. Dimensions, load ratings, designation meaning, life estimates and equivalent parts.
51311 specification
| Designation | 51311 |
| Type | Single-direction thrust ball bearing |
| Series | 513 medium |
| Bore diameter d | 55 mm |
| Outside diameter D | 105 mm |
| Basic dynamic load rating C | 101 kN (101,000 N) |
| Basic static load rating C0 | 224 kN (224,000 N) |
| Ratio C0/C | 2.22 |
| Speed guide, grease lubrication | 3,200 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 51311 means
| Code | Meaning |
|---|---|
| 513 | Single-direction thrust ball bearing, medium series (flat seat washers) |
| 11 | bore code "11" = 11 × 5 = 55 mm |
Basic rating life of the 51311
Basic rating life is L10 = (C / P)p million revolutions, where P is the equivalent dynamic load and p = 3 (ball bearing). For a 51311 with C = 101 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 20.2 kN on this bearing. Use the Load Calculator to work out P for your actual radial and axial loads.
Equivalents of the 51311
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 51311 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 51311 belongs to the “513 medium” series. The next size down, the 51310, has a bore of 50 mm and a dynamic rating of 81.9 kN. The next size up, the 51312, has a bore of 60 mm and a rating of 101 kN (+0%).
Common problems on bearings like the 51311
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 51311
What are the dimensions of a 51311 bearing?
The 51311 has a bore of 55 mm and an outside diameter of 105 mm. It is a single-direction thrust ball bearing. Series: 513 medium.
What is the load rating of a 51311 bearing?
In the Rotec AI catalogue the 51311 has a basic dynamic load rating C of 101 kN and a basic static load rating C0 of 224 kN. Always confirm against the manufacturer's current catalogue.
What is the equivalent of a 51311 bearing?
Use the Cross-Reference tool in Rotec AI to check brand equivalents for the 51311.