81140-M bearing: complete specifications & equivalents
The 81140-M is a ISO 104 radial bearing sized 200 x 250 x 37 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 200 mm |
| Outer diameter D | 250 mm |
| Width B | 37 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 310 kN |
| Basic static load rating C0 | 1500 kN |
| Fatigue load limit Pu | 125 kN |
| Reference speed (thermal) | 700 rpm |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4950 g |
| Manufacturer designation | 81140 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 | 7.874 in |
|---|---|
| Outer diameter D | 9.843 in |
| Width B | 1.457 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 25 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) | 28 of 34 |
| Bore above smallest 81100-series size | 185 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 81140-M model number is decoded
The light 811 series bearing 81140 M carries pure axial load at low to moderate speed: 310 kN dynamic and 1500 kN static across a 200×250 mm washer pair, 37 mm overall height. The designation 81140 M states 811 series, 200 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 0.18. Selection arithmetic: C 310 kN against C0 1500 kN gives a C0/C ratio of 4.84 — thrust bearings are chosen on static rating and F_a/C0 more often than on L10 life. 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 0.18) is present without clamping the rollers.
Typical equipment & failure modes
Common applications
- 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
- extruder and injection press screw thrust blocks at low speed
Known failure patterns
- roller skidding and raceway glazing once the thrust falls below the catalogue minimum axial load (factor A)
- shaft-washer creep and fretting corrosion on a soft or undersized shaft shoulder
- abrasive paste forming as dust bypasses the housing seals into the open washer set
- 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 200 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 37 mm.
- Do not substitute a thrust ball bearing of the same ISO envelope by rating alone: the cylindrical rollers of 81140 M need different minimum load and lubrication despite the shared 200×250 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 81140 M size.
- The 310/1500 kN ratings assume flat, full-support washer seats; a housing face narrower than the 250 mm washer OD invalidates the rating through edge stress.
- Factor A 0.18 is a mounting requirement, not advice: below the minimum axial load the rollers skid at speed — most "mysterious" early thrust failures are unloaded running.
- The 310/1500 kN ratings and 4950 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
Why does 81140 M need a minimum axial load?
Below factor A 0.18 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.
Can the 81140 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 81140 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 0.18 minimum load is present.
What are the dimensions and ratings of the 81140 M?
A 81140 M measures 200 mm bore × 250 mm outside diameter × 37 mm width (7.874 × 9.843 × 1.457 in). From SKF catalogue PUB BU/P1 17000: dynamic C 310 kN, static C0 1500 kN, fatigue limit Pu 125 kN, reference speed 700 r/min, limiting speed 1,400 r/min, mass about 4950 g. Raceway diameters Ea 206 mm / Eb 243 mm and minimum load factor A 0.18 guide the seat design.
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.