51234 M bearing
170 × 240 mm · dynamic rating 270 kN · static rating 930 kN. Dimensions, load ratings, designation meaning, life estimates and equivalent parts.
51234 M specification
| Designation | 51234 M |
| Type | Single-direction thrust ball bearing |
| Series | 512 light-medium |
| Bore diameter d | 170 mm |
| Outside diameter D | 240 mm |
| Basic dynamic load rating C | 270 kN (270,000 N) |
| Basic static load rating C0 | 930 kN (930,000 N) |
| Ratio C0/C | 3.44 |
| Speed guide, grease lubrication | 1,700 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 51234 M means
| Code | Meaning |
|---|---|
| 512 | Single-direction thrust ball bearing, light-medium series (flat seat washers) |
| 34 M | bore code "34 M" = 34 × 5 = 170 mm |
Basic rating life of the 51234 M
Basic rating life is L10 = (C / P)p million revolutions, where P is the equivalent dynamic load and p = 3 (ball bearing). For a 51234 M with C = 270 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 54 kN on this bearing. Use the Load Calculator to work out P for your actual radial and axial loads.
Equivalents of the 51234 M
Brand-by-brand equivalents for this exact designation are not yet in the Rotec AI cross-reference tables. The Cross-Reference tool accepts SKF, FAG, NSK, NTN, Timken, Koyo and NRB designations, and shows what is catalogued.
Where the 51234 M 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 51234 M is size 25 of 28 in the Rotec AI catalogue for the “512 light-medium” series. The next size down, the 51232 M, has a bore of 160 mm and a dynamic rating of 238 kN. The next size up, the 51236 M, has a bore of 180 mm and a rating of 302 kN (+12%).
Common problems on bearings like the 51234 M
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 51234 M
What are the dimensions of a 51234 M bearing?
The 51234 M has a bore of 170 mm and an outside diameter of 240 mm. It is a single-direction thrust ball bearing. Series: 512 light-medium.
What is the load rating of a 51234 M bearing?
In the Rotec AI catalogue the 51234 M has a basic dynamic load rating C of 270 kN and a basic static load rating C0 of 930 kN. Always confirm against the manufacturer's current catalogue.
What is the equivalent of a 51234 M bearing?
Brand equivalents for the 51234 M are not yet in the Rotec AI tables. Use the Cross-Reference tool to check other designations.