81260-M bearing: complete specifications & equivalents
The 81260-M is a ISO 104 radial bearing sized 300 x 420 x 95 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 300 mm |
| Outer diameter D | 420 mm |
| Width B | 95 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1530 kN |
| Basic static load rating C0 | 7200 kN |
| Fatigue load limit Pu | 540 kN |
| Reference speed (thermal) | 320 rpm |
| Limiting speed (mechanical) | 630 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 43000 g |
| Manufacturer designation | 81260 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 | 11.811 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 3.74 in |
| ISO bore code | 60 |
| Radial section height (D−d)/2 | 60 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) | 28 of 28 |
| Bore above smallest 81200-series size | 270 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 81260-M model number is decoded
Where a thrust ball bearing of the same envelope is exhausted, 81260 M replaces the ball complement with cylindrical rollers: 300 mm bore, 420 mm OD, rated 7200 kN static for steady hook and screw loads. Reading the code: the first three digits 812 give the dimension series (heavy 812 series), the last two 60 encode the 300 mm shaft washer bore (code 60 × 5), and M names the cage execution. 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 4.1. Minimum axial load is explicit at factor A 4.1: 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. In vertical shafts let the rotor weight provide the minimum load where possible; otherwise fit a spring pack above the housing washer, and verify the washer face is flooded with oil at first start.
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
- smearing at roller-raceway contacts during unloaded startup before the oil film or preload is established
- housing-washer rotation scored into an unmachined or loose seating face
- oil starvation at the sliding contact zones of large spherical roller thrust bearings on forced-feed trips
- condensation pitting in machines that run intermittently in humid environments
- cage wear from rollers being dragged through unloaded zones under fluctuating thrust
Selection pitfalls — read before you substitute
- At 300 mm bore the 43 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.
- 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 81260 M size.
- the 320 r/min reference speed is the thermal criterion under load, the 630 r/min limiting speed is mechanical and oil lubrication typically raises the usable figure.
- Factor A 4.1 is a mounting requirement, not advice: below the minimum axial load the rollers skid at speed — most "mysterious" early thrust failures are unloaded running.
- 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 1530/7200 kN ratings and 43000 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 a thrust ball bearing replace the 81260 M?
They share ISO boundary outlines (e.g. 511 vs 811), but the roller bearing needs a higher minimum axial load and different lubrication, and its C/C0 figures are not interchangeable — re-run the selection before substituting.
What ruins a 81260 M in service?
Unloaded running below factor A 4.1 causes skidding; non-square or narrow shoulders fret the washer backs; dry starts and contamination do the rest. Speed ceiling: 630 r/min limiting.
Which dimensions does the 81260 M have?
A 81260 M measures 300 mm bore × 420 mm outside diameter × 95 mm width (11.811 × 16.535 × 3.74 in). From SKF catalogue PUB BU/P1 17000: dynamic C 1530 kN, static C0 7200 kN, fatigue limit Pu 540 kN, reference speed 320 r/min, limiting speed 630 r/min, mass about 43000 g. Raceway diameters Ea 329 mm / Eb 412 mm and minimum load factor A 4.1 guide the seat design.
What is the difference between 811 and 812 series?
811 is the light section and 812 the higher, heavier section for the same bore; 893/894 are the extra-heavy series. 81260 M belongs to the heavy 812 series, 300×420×95 mm.
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.