K40X48X20 bearing: complete specifications & equivalents
The K40X48X20 is a DIN 5402 radial bearing sized 40 x 48 x 20 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 | 48 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 34.7 kN |
| Basic static load rating C0 | 58.5 kN |
| Fatigue load limit Pu | 7.35 kN |
| Reference speed (thermal) | 10000 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 49 g |
| Manufacturer designation | K 40x48x20 |
| Standard | DIN 5402 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies); 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 & K-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 1.89 in |
| Width B | 0.787 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 4 mm |
| Smallest bore in K-series | 3 mm |
| Largest outer diameter in K-series | 63 mm |
| Width range across K-series | 7–32 mm |
| Bore position in K-series (smallest first) | 16 of 22 |
| Bore above smallest K-series size | 37 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the K40X48X20 model number is decoded
In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 40x48x20 appears as a needle roller and cage assembly with complement diameter E 48 mm and width 20 mm — a self-contained roller set that turns a 40 mm shaft and its housing into a complete bearing. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 40 (shaft journal), E 48 (assembly outside diameter) and B 20 (width) in millimetres — the machine parts complete the bearing. No suffix on the order number means the standard single-row assembly; the polymer TN cage version is the usual choice for grease-lubricated pivots where noise matters. Speed planning separates the two ceilings: 10,000 r/min thermal reference and 11,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 40 mm seat. Mounting: grind the 40 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 48 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.
Typical equipment & failure modes
Common applications
- rocker arm and rocker pin pivots on camshafts
- pump and gearbox idler gears running on hardened pins
- hinge and pivot joints in printing and textile machinery
- universal joint crosses on commercial vehicles
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- cage pocket wear and roller skew after sustained operation with too little radial preload
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- rolling-contact fatigue spalling after the rated L10 life
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- At 40 mm bore, verify shaft deflection against the needle length: these rollers tolerate little edge loading, and a simply supported span between 40 mm seats can bend past the compensation range long before the load rating is exhausted.
- Reference and limiting speeds are different limits: the 10,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- Hardness is load capacity: in families without an inner ring the 40 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.
- The 34.7/58.5 kN ratings and 49 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 618); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What does K 40x48x20 mean in SKF part numbering?
K = needle roller and cage assembly (DIN 5402); the three figures give Fw 40 mm (shaft journal), E 48 mm (complement outside diameter, matched by the housing bore) and B 20 mm width. TN marks the glass fibre reinforced PA66 cage.
Does the K 40x48x20 need a hardened and ground shaft?
No. In this execution the 40 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead.
What mounting mistakes ruin a K 40x48x20?
Slide the assembly over the ground 40 mm journal with a mounting sleeve, bore the housing to E 48 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded.
Is the K 40x48x20 sealed?
No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies on 2026-09-26. Read our editorial & correction policy.