C3148 bearing: complete specifications & equivalents
The C3148 is a ISO 15 radial bearing sized 240 x 400 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 | 240 mm |
| Outer diameter D | 400 mm |
| Width B | 128 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 2320 kN |
| Basic static load rating C0 | 3450 kN |
| Fatigue load limit Pu | 285 kN |
| Reference speed (thermal) | 1300 rpm |
| Limiting speed (mechanical) | 1700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 64000 g |
| Manufacturer designation | C 3148 |
| 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 & C3100-series range
| Bore d | 9.449 in |
|---|---|
| Outer diameter D | 15.748 in |
| Width B | 5.039 in |
| ISO bore code | 48 |
| Radial section height (D−d)/2 | 80 mm |
| Smallest bore in C3100-series | 100 mm |
| Largest outer diameter in C3100-series | 1580 mm |
| Width range across C3100-series | 52–462 mm |
| Bore position in C3100-series (smallest first) | 8 of 28 |
| Bore above smallest C3100-series size | 140 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C3148-K | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 240×400×128 mm ISO 15 envelope and equivalent catalogue C/C0; C 3148 K is the 1:12 tapered-bore K steel-caged execution of this size — boundary dimensions interchangeable, only mounting and cage execution differ. |
| 23148 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (240×400×128 mm) SKF spherical roller bearing SKF 23148 CC/W33 with ratings within 10 % — not a drop-in substitute: SKF 23148 CC/W33 locates the shaft axially while the CARB bearing must float; the two are designed to run as a locating/non-locating pair. |
| 23148-CCK-W33 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (240×400×128 mm) SKF spherical roller bearing SKF 23148 CCK/W33 with ratings within 10 % — not a drop-in substitute: SKF 23148 CCK/W33 locates the shaft axially while the CARB bearing must float; the two are designed to run as a locating/non-locating pair. |
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 C3148 model number is decoded
C 3148 is a CARB toroidal roller bearing to ISO 15: a single row of long, symmetrical barrel-shaped rollers between guide flanges, sized 240×400×128 mm, as listed in SKF catalogue PUB BU/P1 17000 ch. 10.1. Reading the code: C marks the CARB toroidal family, the first two digits (31) identify the ISO dimension series and the last two (48) encode the 240 mm bore; suffixes describe bore and execution. The unsuffixed execution carries a pressed steel window cage — the balanced standard for the 240×400 mm size with 2320 kN dynamic and a 1,300 r/min reference speed. Selection arithmetic: C 2320 kN against C0 3450 kN gives a C0/C ratio of 1.49, and the 285 kN fatigue load limit Pu sets the contamination-adjusted life floor. Mounting: slide the bearing onto the 240 mm seat or heat it (max 120 °C) and seat it square; never press through the 128 mm roller set, and leave the free-end housing shoulder clear so axial float is unrestricted.
Typical equipment & failure modes
Common applications
- 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
- winder and reel drums in paper and steel strip plants
- paper machine drying cylinders and calender rolls with long, thermally expanding shafts
Known failure patterns
- roller-end and flange smearing after lubricant starvation at the long roller contacts
- roller skew and cage damage after the bearing is clamped solid between shaft and housing shoulders
- PA66 cage (TN9) softening when the sustained temperature passes the polymer limit
- rolling-contact fatigue spalling after the catalogue L10 life is exhausted
- abrasive paste forming as dust bypasses the housing seals into the open washer set
Selection pitfalls — read before you substitute
- Above 200 mm bore these bearings weigh tens of kilograms (64 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 240 mm bore changes the sleeve family, and the drive-up procedure differs accordingly.
- Reference and limiting speeds are different limits: the 1,300 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.
- Envelope-identical spherical roller bearings (same ISO 15 d×D×B) are not drop-in equivalents — they locate the shaft axially, while C 3148 must float; the two are designed to be used as a pair.
- Never use C 3148 as the locating bearing: it carries no axial load by design — the arrangement needs a separate locating spherical, tapered or angular bearing facing the thrust.
- The 2320/3450 kN ratings and 64000 g mass are SKF catalogue values transcribed from ch. 10.1 of PUB BU/P1 17000 (PDF table page 864); 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
What does C 3148 mean in SKF part numbering?
C marks CARB; 31 the dimension series; the size code gives 240 mm bore; the bare number is the execution (cylindrical bore for direct shaft fitting, pressed steel cage). The envelope follows ISO 15 and matches spherical roller bearing outlines, but the functions differ.
Why is C 3148 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 3148 sealed?
No, it is an open execution relying on the housing seals; relubrication follows the groove/hole features of the size.
What fails first on a misapplied CARB bearing?
Blocking the designed axial float — clamping the free end or locating both shaft ends — turns thermal growth into edge loading and spalls the toroidal raceways. Cage damage and ordinary fatigue follow overload or dry running.
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.