81108-TN bearing: complete specifications & equivalents
The 81108-TN is a ISO 104 radial bearing sized 40 x 60 x 13 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 60 mm |
| Width B | 13 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 43 kN |
| Basic static load rating C0 | 137 kN |
| Fatigue load limit Pu | 13.7 kN |
| Reference speed (thermal) | 2400 rpm |
| Limiting speed (mechanical) | 5000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 110 g |
| Manufacturer designation | 81108 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 | 1.575 in |
|---|---|
| Outer diameter D | 2.362 in |
| Width B | 0.512 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 10 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) | 7 of 34 |
| Bore above smallest 81100-series size | 25 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 81108-TN model number is decoded
81108 TN is the rigid-washer thrust solution for a 40 mm shaft: unlike ball thrust types, the line contact of cylindrical rollers gives 43 kN C within just 13 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 08 encode the 40 mm shaft washer bore (code 08 × 5), and TN names the cage execution. Rigid washers mean no self-alignment: the shaft and housing shoulders must be square and parallel to within the catalogue seat tolerances, or the rollers edge-load across the 13 mm height. Static safety matters for shock duty: compare peak axial force against C0 137 kN with the application's static factor, since crane hooks and screw positions see their worst load at zero or low speed. 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
- 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
- screw jack and lifting screw thrust positions under slow, steady load
Known failure patterns
- smearing at roller-raceway contacts during unloaded startup before the oil film or preload is established
- shaft-washer creep and fretting corrosion on a soft or undersized shaft shoulder
- grease churning and overheating when a high-speed thrust position is over-packed
- 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 a 40 mm seat the 13 mm stack is easy to over-clamp — a cover torqued solid removes all roller clearance; shim to the catalogue endplay and keep factor A 0.0015 as the floor.
- 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 81108 TN size.
- the 2,400 r/min reference speed is the thermal criterion under load, the 5,000 r/min limiting speed is mechanical and oil lubrication typically raises the usable figure.
- Do not substitute a thrust ball bearing of the same ISO envelope by rating alone: the cylindrical rollers of 81108 TN need different minimum load and lubrication despite the shared 40×60 mm outline.
- The 43/137 kN ratings assume flat, full-support washer seats; a housing face narrower than the 60 mm washer OD invalidates the rating through edge stress.
- The 43/137 kN ratings and 110 g mass are SKF catalogue values transcribed from ch. 11.1 of PUB BU/P1 17000 (PDF table page 890); 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
What ruins a 81108 TN in service?
Unloaded running below factor A 0.0015 causes skidding; non-square or narrow shoulders fret the washer backs; dry starts and contamination do the rest. Speed ceiling: 5,000 r/min limiting.
Which dimensions does the 81108 TN have?
A 81108 TN measures 40 mm bore × 60 mm outside diameter × 13 mm width (1.575 × 2.362 × 0.512 in). From SKF catalogue PUB BU/P1 17000: dynamic C 43 kN, static C0 137 kN, fatigue limit Pu 13.7 kN, reference speed 2,400 r/min, limiting speed 5,000 r/min, mass about 110 g. Raceway diameters Ea 42 mm / Eb 58 mm and minimum load factor A 0.0015 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. 81108 TN belongs to the light 811 series, 40×60×13 mm.
Are the washers of 81108 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.
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.