81118-TN bearing: complete specifications & equivalents
The 81118-TN is a ISO 104 radial bearing sized 90 x 120 x 22 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 90 mm |
| Outer diameter D | 120 mm |
| Width B | 22 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 110 kN |
| Basic static load rating C0 | 450 kN |
| Fatigue load limit Pu | 45.5 kN |
| Reference speed (thermal) | 1300 rpm |
| Limiting speed (mechanical) | 2600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 620 g |
| Manufacturer designation | 81118 TN |
| 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 | 3.543 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 0.866 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 15 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) | 17 of 34 |
| Bore above smallest 81100-series size | 75 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 81118-TN model number is decoded
The light 811 series bearing 81118 TN carries pure axial load at low to moderate speed: 110 kN dynamic and 450 kN static across a 90×120 mm washer pair, 22 mm overall height. Reading the code: the first three digits 811 give the dimension series (light 811 series), the last two 18 encode the 90 mm shaft washer bore (code 18 × 5), and TN 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 0.016. Speed planning separates the 1,300 r/min thermal reference from the 2,600 r/min mechanical limiting speed. Thrust bearings govern the thermal speed of many vertical arrangements, and oil circulation raises the usable speed substantially above grease values. Mounting: locate the shaft washer on the 90 mm seat (it rotates and takes an interference fit), leave the housing washer a sliding fit in the 120 mm bore, and check the stack can tilt freely before clamping.
Typical equipment & failure modes
Common applications
- 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
- rolling-mill screwdown mechanisms and press adjusters
Known failure patterns
- cage wear from rollers being dragged through unloaded zones under fluctuating thrust
- washer back-face fretting where the seat is too narrow to support the full ring face
- grease churning and overheating when a high-speed thrust position is over-packed
- rolling-contact fatigue spalling after the catalogue L10 life is exhausted
- roller skidding and raceway glazing once the thrust falls below the catalogue minimum axial load (factor A)
Selection pitfalls — read before you substitute
- At 90 mm bore the minimum load (A 0.016) is still small, but a vertical shaft at rest loses it entirely — specify springs or check the rotor weight exceeds F_am at zero speed.
- Keep the glass fibre reinforced PA66 TN cage out of chemical contact with aggressive EP additives beyond its compatibility list; cage damage here redistributes rollers and destroys the washer in hours.
- Do not substitute a thrust ball bearing of the same ISO envelope by rating alone: the cylindrical rollers of 81118 TN need different minimum load and lubrication despite the shared 90×120 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 81118 TN size.
- the 1,300 r/min reference speed is the thermal criterion under load, the 2,600 r/min limiting speed is mechanical and oil lubrication typically raises the usable figure.
- The 110/450 kN ratings and 620 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
Which dimensions does the 81118 TN have?
A 81118 TN measures 90 mm bore × 120 mm outside diameter × 22 mm width (3.543 × 4.724 × 0.866 in). From SKF catalogue PUB BU/P1 17000: dynamic C 110 kN, static C0 450 kN, fatigue limit Pu 45.5 kN, reference speed 1,300 r/min, limiting speed 2,600 r/min, mass about 620 g. Raceway diameters Ea 93 mm / Eb 117 mm and minimum load factor A 0.016 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. 81118 TN belongs to the light 811 series, 90×120×22 mm.
Are the washers of 81118 TN separable?
Yes — shaft washer WS, roller-and-cage set and housing washer GS are separate and interchangeable within the size, but never across series: an 811 and an 812 washer for the same bore differ in OD and height.
Can a thrust ball bearing replace the 81118 TN?
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.
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.