81232-M bearing: complete specifications & equivalents
The 81232-M is a ISO 104 radial bearing sized 160 x 225 x 51 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 160 mm |
| Outer diameter D | 225 mm |
| Width B | 51 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 480 kN |
| Basic static load rating C0 | 2000 kN |
| Fatigue load limit Pu | 176 kN |
| Reference speed (thermal) | 600 rpm |
| Limiting speed (mechanical) | 1200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 7600 g |
| Manufacturer designation | 81232 M |
| Standard | ISO 104 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 11.1 cylindrical roller thrust bearings |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 11.1 cylindrical roller thrust bearings) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 11.1 cylindrical roller thrust bearings); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & 81200-series range
| Bore d | 6.299 in |
|---|---|
| Outer diameter D | 8.858 in |
| Width B | 2.008 in |
| ISO bore code | 32 |
| Radial section height (D−d)/2 | 32.5 mm |
| Smallest bore in 81200-series | 30 mm |
| Largest outer diameter in 81200-series | 420 mm |
| Width range across 81200-series | 16–95 mm |
| Bore position in 81200-series (smallest first) | 20 of 28 |
| Bore above smallest 81200-series size | 130 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 81232-M model number is decoded
SKF supplies 81232 M as a separable thrust bearing: the 160 mm shaft washer (WS), the machined brass M cage holding short cylindrical rollers, and the 225 mm housing washer (GS) can be ordered and mounted individually. In 81232 M, 812 fixes the 225 mm OD and 51 mm height; 32 selects the 160 mm seat, and the machined brass M cage is the only execution suffix on these rigid-washer bearings. Rigid washers mean no self-alignment: the shaft and housing shoulders must be square and parallel to within the catalogue seat tolerances, or the rollers edge-load across the 51 mm height. Minimum axial load is explicit at factor A 0.32: below F_am = A·n² (or the catalogue's slow-speed floor) the cylindrical rollers skid; springs or the rotor's own weight are part of the selection, not an accessory. Press only on washer backs, never through the roller set; seat both washers against full-area square shoulders, and shim the housing cover so the minimum load (A 0.32) is present without clamping the rollers.
Typical equipment & failure modes
Common applications
- vertical electric motor and pump shafts whose rotor weight loads one bearing
- extruder and injection press screw thrust blocks at low speed
- rolling-mill screwdown mechanisms and press adjusters
- slewing and turntable pivots with predominantly axial force
Known failure patterns
- roller skidding and raceway glazing once the thrust falls below the catalogue minimum axial load (factor A)
- washer back-face fretting where the seat is too narrow to support the full ring face
- oil starvation at the sliding contact zones of large spherical roller thrust bearings on forced-feed trips
- electrical erosion of raceways on VFD-driven shafts without grounding or insulation
- smearing at roller-raceway contacts during unloaded startup before the oil film or preload is established
Selection pitfalls — read before you substitute
- At 160 mm bore the washers are too stiff to conform to a non-square seat: machine the shoulders parallel or the roller ends concentrate load into a narrow stripe across 51 mm.
- Do not substitute a thrust ball bearing of the same ISO envelope by rating alone: the cylindrical rollers of 81232 M need different minimum load and lubrication despite the shared 160×225 mm outline.
- The separable washers are not interchangeable across series: an 811 and an 812 washer for the same bore differ in OD and height — order WS/GS parts by the full 81232 M size.
- Keep the machined brass M cage out of chemical contact with aggressive EP additives beyond its compatibility list; cage damage here redistributes rollers and destroys the washer in hours.
- the 600 r/min reference speed is the thermal criterion under load, the 1,200 r/min limiting speed is mechanical and oil lubrication typically raises the usable figure.
- The 480/2000 kN ratings and 7600 g mass are SKF catalogue values transcribed from ch. 11.1 of PUB BU/P1 17000 (PDF table page 892); mounting data — Ea/Eb raceway diameters and the minimum load factor A — appears in the running text because the structured record carries the boundary envelope only.
Frequently asked questions
How should a 81232 M be mounted?
Interference fit for the shaft washer, sliding fit for the housing washer, full-area square shoulders both sides, press on washer backs only, and shim the cover so the rollers turn freely while the factor-A 0.32 minimum load is present.
What are the dimensions and ratings of the 81232 M?
A 81232 M measures 160 mm bore × 225 mm outside diameter × 51 mm width (6.299 × 8.858 × 2.008 in). From SKF catalogue PUB BU/P1 17000: dynamic C 480 kN, static C0 2000 kN, fatigue limit Pu 176 kN, reference speed 600 r/min, limiting speed 1,200 r/min, mass about 7600 g. Raceway diameters Ea 171 mm / Eb 219 mm and minimum load factor A 0.32 guide the seat design.
How is the 81232 M designation read?
The first three digits 812 give the dimension series (heavy 812 series); 32 encodes the 160 mm bore (code 32 × 5); the suffix denotes the machined brass M cage. WS and GS washers of the same size can be ordered separately.
Why does 81232 M need a minimum axial load?
Below factor A 0.32 the cylindrical rollers skid instead of rolling, glazing and smearing the washer tracks. Springs, preload shims or rotor weight must keep the thrust above the catalogue minimum, especially during unloaded starts.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 11.1 cylindrical roller thrust bearings on 2026-09-27. Read our editorial & correction policy.