C39-500-KM bearing: complete specifications & equivalents
The C39-500-KM is a ISO 15 radial bearing sized 500 x 670 x 128 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 500 mm |
| Outer diameter D | 670 mm |
| Width B | 128 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 3150 kN |
| Basic static load rating C0 | 6300 kN |
| Fatigue load limit Pu | 430 kN |
| Reference speed (thermal) | 700 rpm |
| Limiting speed (mechanical) | 950 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 125000 g |
| Manufacturer designation | C 39/500 KM |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller 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 & C3900-series range
| Bore d | 19.685 in |
|---|---|
| Outer diameter D | 26.378 in |
| Width B | 5.039 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 85 mm |
| Smallest bore in C3900-series | 360 mm |
| Largest outer diameter in C3900-series | 2180 mm |
| Width range across C3900-series | 90–355 mm |
| Bore position in C3900-series (smallest first) | 5 of 15 |
| Bore above smallest C3900-series size | 140 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C39-500-M | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 500×670×128 mm ISO 15 envelope and equivalent catalogue C/C0; C 39/500 M is the cylindrical-bore M brass-caged execution of this size — boundary dimensions interchangeable, only mounting and cage execution differ. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the C39-500-KM model number is decoded
The CARB bearing C 39/500 KM combines the self-aligning behaviour of a spherical roller bearing with the axial freedom of a cylindrical bearing in one 500 mm bore, 670 mm outside diameter, 128 mm wide unit rated 3150 kN dynamic. Reading the code: C marks the CARB toroidal family, the first two digits (39) identify the ISO dimension series and the last two (500 mm (slash-size)) encode the 500 mm bore; suffixes describe bore and execution. The KM suffix is a one-piece machined brass cage centred on the rollers, supplied for the 500 mm and larger sizes needing robust guidance under heavy load. Float capacity is a selection criterion: the catalogue lists the permissible axial displacement (s) for the 128 mm wide set; size the free-end housing so thermal growth stays within it, not just inside the overall width. Seat tolerances follow the ISO 15 recommendation for the heavy-loaded position — the 670 mm outer ring typically takes a loose housing fit to preserve float, and the rings must be supported across their full faces.
Typical equipment & failure modes
Common applications
- continuous-caster guide rolls and slab-caster segments under heat growth
- vibrating screen exciters fitted with the VE240 tolerance execution
- long fan and kiln main shafts where the free end must float without thrust load
- heavy industrial gearbox layshafts used as the non-locating position
Known failure patterns
- roller-end and flange smearing after lubricant starvation at the long roller contacts
- edge loading and premature spalling when the CARB position is blocked from its designed axial float
- PA66 cage (TN9) softening when the sustained temperature passes the polymer limit
- rolling-contact fatigue spalling after the catalogue L10 life is exhausted
- oil starvation at the sliding contact zones of large spherical roller thrust bearings on forced-feed trips
Selection pitfalls — read before you substitute
- Above 200 mm bore these bearings weigh tens of kilograms (125 kg here) — lifting gear and induction heating are mandatory, and a cocked ring scores the toroidal raceway before start-up.
- Tapered-bore K executions mount on adapter sleeves (1:12) and K30 on withdrawal sleeves (1:30) — the 500 mm bore changes the sleeve family, and the drive-up procedure differs accordingly.
- Reference and limiting speeds are different limits: the 700 r/min reference speed is the thermal criterion under load, the limiting value is the mechanical ceiling; observe the reference under load unless the arrangement calculation says otherwise.
- The quoted 3150/6300 kN ratings belong to this exact execution (C 39/500 KM); VE240 vibrating-screen variants and sealed 2CS/2NS variants have their own figures even at the same envelope.
- Do not block the axial displacement in the drawing: housing covers, labyrinth rings and snap rings must leave the catalogue float (s) free, or the bearing silently becomes a poorly located fixed bearing.
- The 3150/6300 kN ratings and 125000 g mass are SKF catalogue values transcribed from ch. 10.1 of PUB BU/P1 17000 (PDF table page 866); mounting data — axial displacement (s) and seating details — appears in the running text because the structured record carries the boundary envelope only.
Frequently asked questions
Which dimensions does the C 39/500 KM have?
A C 39/500 KM measures 500 mm bore × 670 mm outside diameter × 128 mm width (19.685 × 26.378 × 5.039 in). From SKF catalogue PUB BU/P1 17000: dynamic C 3150 kN, static C0 6300 kN, fatigue limit Pu 430 kN, reference speed 700 r/min, limiting speed 950 r/min, mass about 125000 g.
What does C 39/500 KM mean in SKF part numbering?
C marks CARB; 39 the dimension series; the size code gives 500 mm bore; KM is the execution (tapered 1:12 bore for adapter (H) sleeve mounting, machined brass M cage). The envelope follows ISO 15 and matches spherical roller bearing outlines, but the functions differ.
Why is C 39/500 KM used opposite a spherical roller bearing?
The spherical bearing locates the shaft and takes thrust; the CARB bearing at the other end self-aligns but floats, absorbing thermal expansion without inducing axial load. The pair is standard on paper machine drying cylinders and long caster rolls.
Is the C 39/500 KM sealed?
No, it is an open execution relying on the housing seals; relubrication follows the groove/hole features of the size.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings on 2026-09-27. Read our editorial & correction policy.