51202 bearing: complete specifications & equivalents
The 51202 is a ISO 104 radial bearing sized 15 x 32 x 12 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 15 mm |
| Outer diameter D | 32 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 16.6 kN |
| Basic static load rating C0 | 24.8 kN |
| Fatigue load limit Pu | 1.12 kN |
| Limiting speed (mechanical) | 5000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 46 g |
| Manufacturer designation | NTN 51202 |
| 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 & 51200-series range
| Bore d | 0.591 in |
|---|---|
| Outer diameter D | 1.26 in |
| Width B | 0.472 in |
| ISO bore code | 02 |
| Radial section height (D−d)/2 | 8.5 mm |
| Smallest bore in 51200-series | 10 mm |
| Largest outer diameter in 51200-series | 520 mm |
| Width range across 51200-series | 11–112 mm |
| Bore position in 51200-series (smallest first) | 3 of 39 |
| Bore above smallest 51200-series size | 5 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51202-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 51202 model number is decoded
51202 is an NTN single-direction thrust ball bearing of the medium-section 51200 thrust family: 15 mm bore, 32 mm outside diameter, 12 mm overall height in NTN Ball and Roller Bearings CAT.No.2203E. Reading the code: 512 is the dimension series (medium-section 51200 thrust family), and the bore code 02 maps to the 15 mm bore by the standard table. The washer section here is 8.5 mm of radial height, and the catalogue couples it with Ca 16.6 kN / C0a 24.8 kN. Size selection ends with the minimum-load check: at the 5,000 r/min class speed, the balls need a defined axial preload to keep rolling instead of skidding. Preload or working clearance must guarantee the minimum axial load at the catalogue speed; a spring or dead-weight arrangement is the usual answer on high-speed vertical shafts.
Typical equipment & failure modes
Common applications
- laboratory centrifuge and mixer thrust ends
- small vertical pump and agitator thrust positions
- bench drill-press and tapping-machine spindles
- automotive steering-gear and clutch release points
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
- rapid flaking after radial load was allowed onto the bearing — a single-direction thrust ball bearing carries axial load only
- contamination pitting from particles settling on the horizontal housing washer — the classic failure of vertical-shaft grease-lubricated seats
- edge loading from a shaft washer mounted off-centre, cutting the contact ellipse short at one side of the track
Selection pitfalls — read before you substitute
- Small thrust washers of 15 mm bore bend if the shaft shoulder is rough — check burrs before seating, and never press on the housing washer to drive the shaft washer home.
- The 512 medium section is the default choice: balanced height and capacity for general vertical-shaft duty at 15 mm bore.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51202 stack height of 12 mm and washer set differ from the double-direction execution.
- Do not reuse a thrust bearing to "absorb" shaft thermal growth — the bearing clamps axially, so growth must be handled on the radial-bearing side of the arrangement.
- The C0a of 24.8 kN is a static rating: sizing continuous working thrust from C0a alone overstates what the raceway survives.
- The Ca 16.6/C0a 24.8 kN ratings and 1.12 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51202; 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 51202?
51202 is a single-direction thrust ball bearing to ISO 104: 15 mm shaft-washer bore, 32 mm outside diameter, 12 mm stack height (0.591 x 1.26 x 0.472 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 16.6 kN, C0a 24.8 kN and a 1.12 kN fatigue load limit Pu; the grease limiting speed is 5,000 r/min and the oil rating 7,100 r/min; mass about 46 g.
How is the 51202 designation structured?
512 is the dimension series (medium-section 51200 thrust family); the bore code 02 maps to the 15 mm bore by the standard table. The 32 mm OD and 12 mm height follow the ISO 104 boundary plan for that series.
Can 51202 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 51202?
At the 5,000 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 51202?
The 15/32/12 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 16.6 kN / C0a 24.8 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.