51118 bearing: complete specifications & equivalents
The 51118 is a ISO 104 radial bearing sized 90 x 120 x 22 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 90 mm |
| Outer diameter D | 120 mm |
| Width B | 22 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 59.5 kN |
| Basic static load rating C0 | 190 kN |
| Fatigue load limit Pu | 8.35 kN |
| Limiting speed (mechanical) | 1900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 687 g |
| Manufacturer designation | NTN 51118 |
| Standard | ISO 104 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & 51100-series range
| Bore d | 3.543 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 0.866 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 15 mm |
| Smallest bore in 51100-series | 10 mm |
| Largest outer diameter in 51100-series | 640 mm |
| Width range across 51100-series | 9–85 mm |
| Bore position in 51100-series (smallest first) | 19 of 46 |
| Bore above smallest 51100-series size | 80 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51118-SKF | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 51118 model number is decoded
51118 is an NTN single-direction thrust ball bearing of the light-section 51100 thrust family: 90 mm bore, 120 mm outside diameter, 22 mm overall height in NTN Ball and Roller Bearings CAT.No.2203E. The designation is 511 is the dimension series (light-section 51100 thrust family) plus 18 encodes the 90 mm bore (bore code x 5). The ball-and-cage set is separable from both washers, which is why the mounting order (shaft washer first, then cage, then housing washer) matters. Against a thrust roller bearing of the same 90 mm bore, this bearing is cheaper, quieter and happier at speed, but carries far less load per mm of section. Keep the support faces square: a housing face out of perpendicular by a few hundredths over the 120 mm OD already tilts the raceway and concentrates the 190 kN static capacity on a few balls.
Typical equipment & failure modes
Common applications
- vertical water-pump and turbine thrust blocks
- large crane hook and swivel assemblies
- rolling-mill screwdown and adjustment screws
- heavy press and forging-machine thrust seats
Known failure patterns
- cage pocket wear and ball skid polish after long running below the minimum axial load, the balls sliding instead of rolling on the washers
- housing-washer rocking on an out-of-square support face, seen as uneven wear around the raceway circle and rising running torque
- early fatigue from thrust reversal hammering the unloaded raceway, because the bearing has no contact surfaces for the opposite direction
- cage breakage after repeated shock reversal banged the ball set against the pocket bridges
- contamination pitting from particles settling on the horizontal housing washer — the classic failure of vertical-shaft grease-lubricated seats
Selection pitfalls — read before you substitute
- At 90 mm bore the washers are heavy enough to sag out of square during assembly — support the stack horizontally where possible and verify face runout before loading.
- The 511 light section is the speed-friendly end of the thrust-ball plan — for the same 90 mm bore it gives up load to gain OD, height and limiting-speed headroom.
- Shock thrust above C0a 190 kN leaves dents that later become fatigue origins — crane-hook and press applications need the static check, not just the life calculation.
- Shock thrust above C0a 190 kN leaves dents that later become fatigue origins — crane-hook and press applications need the static check, not just the life calculation.
- Radial load is the silent killer here: a belt pull or gear force on the same shaft must land on a radial bearing, because 51118 has no radial capacity at all.
- The Ca 59.5/C0a 190 kN ratings and 8.35 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51118; raceway geometry legitimately differs between manufacturers, so re-verify ratings and washer identification before substituting another make.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 51118?
51118 is a single-direction thrust ball bearing to ISO 104: 90 mm shaft-washer bore, 120 mm outside diameter, 22 mm stack height (3.543 x 4.724 x 0.866 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 59.5 kN, C0a 190 kN and a 8.35 kN fatigue load limit Pu; the grease limiting speed is 1,900 r/min and the oil rating 2,700 r/min; mass about 687 g.
How is the 51118 designation structured?
511 is the dimension series (light-section 51100 thrust family); 18 encodes the 90 mm bore (bore code x 5). The 120 mm OD and 22 mm height follow the ISO 104 boundary plan for that series.
Can 51118 carry radial load or reversing thrust?
No. The raceways contact the balls at 90 deg to the shaft, so the rating is purely axial and single-direction. Radial load must be carried by a separate radial bearing, and reversing thrust needs a second thrust bearing or a double-direction execution.
Why does NTN specify a minimum axial load for 51118?
At the 1,900 r/min class speed, centrifugal and gyroscopic effects make an under-loaded ball set skid and smear instead of roll. The catalogue minimum-load formula gives the axial preload — from the machine weight, springs or a dead-weight — that keeps the contact rolling.
What should be checked before substituting another make for 51118?
The 90/120/22 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 59.5 kN / C0a 190 kN, the speed figures and the shaft/housing washer identification against the donor catalogue.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.