81156-M bearing: complete specifications & equivalents
The 81156-M is a ISO 104 radial bearing sized 280 x 350 x 53 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 280 mm |
| Outer diameter D | 350 mm |
| Width B | 53 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 680 kN |
| Basic static load rating C0 | 3550 kN |
| Fatigue load limit Pu | 275 kN |
| Reference speed (thermal) | 480 rpm |
| Limiting speed (mechanical) | 950 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 12500 g |
| Manufacturer designation | 81156 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 & 81100-series range
| Bore d | 11.024 in |
|---|---|
| Outer diameter D | 13.78 in |
| Width B | 2.087 in |
| ISO bore code | 56 |
| Radial section height (D−d)/2 | 35 mm |
| Smallest bore in 81100-series | 15 mm |
| Largest outer diameter in 81100-series | 400 mm |
| Width range across 81100-series | 9–63 mm |
| Bore position in 81100-series (smallest first) | 32 of 34 |
| Bore above smallest 81100-series size | 265 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 81156-M model number is decoded
SKF supplies 81156 M as a separable thrust bearing: the 280 mm shaft washer (WS), the machined brass M cage holding short cylindrical rollers, and the 350 mm housing washer (GS) can be ordered and mounted individually. The designation 81156 M states 811 series, 280 mm bore, machined brass M cage; shaft and housing washers are also orderable separately as WS and GS parts of the same size. The bearing takes thrust in one direction only — reverse loads lift the roller set off its track; arrange a mirrored second bearing for reversing duty, and keep the applied load above factor A 1. One direction only: 81156 M cannot be reversed to take opposite thrust — mirror a second bearing for reversing shafts, and keep housing and shaft seats square within the ISO 104 tolerances. 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 1) is present without clamping the rollers.
Typical equipment & failure modes
Common applications
- slewing and turntable pivots with predominantly axial force
- crane hook crossheads carrying pure hook thrust while the hook swivels
- screw jack and lifting screw thrust positions under slow, steady load
- vertical electric motor and pump shafts whose rotor weight loads one bearing
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
- brinelling of washer raceways from impact or mounting force applied through the rolling elements
- smearing at roller-raceway contacts during unloaded startup before the oil film or preload is established
Selection pitfalls — read before you substitute
- At 280 mm bore the 12.5 kg washer set needs forced lubrication and controlled start-up sequencing; dry first rotation under load is the classic destruction mode for very large thrust bearings.
- Do not substitute a thrust ball bearing of the same ISO envelope by rating alone: the cylindrical rollers of 81156 M need different minimum load and lubrication despite the shared 280×350 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 81156 M size.
- the 480 r/min reference speed is the thermal criterion under load, the 950 r/min limiting speed is mechanical and oil lubrication typically raises the usable figure.
- The 680/3550 kN ratings assume flat, full-support washer seats; a housing face narrower than the 350 mm washer OD invalidates the rating through edge stress.
- The 680/3550 kN ratings and 12500 g mass are SKF catalogue values transcribed from ch. 11.1 of PUB BU/P1 17000 (PDF table page 894); 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
Can the 81156 M take reversing thrust?
No. It carries axial load in one direction only; reversing force unloads and impacts the roller set. Use a mirrored pair of bearings for reversing shafts, with a separate arrangement for radial load.
How should a 81156 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 1 minimum load is present.
What are the dimensions and ratings of the 81156 M?
A 81156 M measures 280 mm bore × 350 mm outside diameter × 53 mm width (11.024 × 13.78 × 2.087 in). From SKF catalogue PUB BU/P1 17000: dynamic C 680 kN, static C0 3550 kN, fatigue limit Pu 275 kN, reference speed 480 r/min, limiting speed 950 r/min, mass about 12500 g. Raceway diameters Ea 288 mm / Eb 346 mm and minimum load factor A 1 guide the seat design.
How is the 81156 M designation read?
The first three digits 811 give the dimension series (light 811 series); 56 encodes the 280 mm bore (code 56 × 5); the suffix denotes the machined brass M cage. WS and GS washers of the same size can be ordered separately.
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.