81122-TN bearing: complete specifications & equivalents
The 81122-TN is a ISO 104 radial bearing sized 110 x 145 x 25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 110 mm |
| Outer diameter D | 145 mm |
| Width B | 25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 163 kN |
| Basic static load rating C0 | 680 kN |
| Fatigue load limit Pu | 65.5 kN |
| Reference speed (thermal) | 1100 rpm |
| Limiting speed (mechanical) | 2200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1050 g |
| Manufacturer designation | 81122 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 | 4.331 in |
|---|---|
| Outer diameter D | 5.709 in |
| Width B | 0.984 in |
| ISO bore code | 22 |
| Radial section height (D−d)/2 | 17.5 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) | 19 of 34 |
| Bore above smallest 81100-series size | 95 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 81122-TN model number is decoded
81122 TN is the rigid-washer thrust solution for a 110 mm shaft: unlike ball thrust types, the line contact of cylindrical rollers gives 163 kN C within just 25 mm of axial space, per the ISO 104 plan. Reading the code: the first three digits 811 give the dimension series (light 811 series), the last two 22 encode the 110 mm shaft washer bore (code 22 × 5), and TN names the cage execution. The three components are separable and interchangeable within the size: WS shaft washer, K-cage roller set, GS housing washer, all running on flat, square seats; the glass fibre reinforced PA66 TN cage is standard for this size. The 1050 g mass and 25 mm axial height sit between 110 and 145 mm washer diameters; check the seat shoulder spans the full ring face — a narrow shoulder causes washer fretting long before fatigue does. 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 0.037) is present without clamping the rollers.
Typical equipment & failure modes
Common applications
- 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
- crane hook crossheads carrying pure hook thrust while the hook swivels
Known failure patterns
- smearing at roller-raceway contacts during unloaded startup before the oil film or preload is established
- 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
- cage wear from rollers being dragged through unloaded zones under fluctuating thrust
Selection pitfalls — read before you substitute
- At 110 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 25 mm.
- 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 81122 TN size.
- the 1,100 r/min reference speed is the thermal criterion under load, the 2,200 r/min limiting speed is mechanical and oil lubrication typically raises the usable figure.
- 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 81122 TN need different minimum load and lubrication despite the shared 110×145 mm outline.
- The 163/680 kN ratings and 1050 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
Are the washers of 81122 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 81122 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.
What ruins a 81122 TN in service?
Unloaded running below factor A 0.037 causes skidding; non-square or narrow shoulders fret the washer backs; dry starts and contamination do the rest. Speed ceiling: 2,200 r/min limiting.
Which dimensions does the 81122 TN have?
A 81122 TN measures 110 mm bore × 145 mm outside diameter × 25 mm width (4.331 × 5.709 × 0.984 in). From SKF catalogue PUB BU/P1 17000: dynamic C 163 kN, static C0 680 kN, fatigue limit Pu 65.5 kN, reference speed 1,100 r/min, limiting speed 2,200 r/min, mass about 1050 g. Raceway diameters Ea 114 mm / Eb 141 mm and minimum load factor A 0.037 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.