C4188-K30MB bearing: complete specifications & equivalents
The C4188-K30MB is a ISO 15 radial bearing sized 440 x 720 x 280 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 440 mm |
| Outer diameter D | 720 mm |
| Width B | 280 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 7500 kN |
| Basic static load rating C0 | 12900 kN |
| Fatigue load limit Pu | 900 kN |
| Reference speed (thermal) | 500 rpm |
| Limiting speed (mechanical) | 670 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 471000 g |
| Manufacturer designation | C 4188 K30MB |
| 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 & C4100-series range
| Bore d | 17.323 in |
|---|---|
| Outer diameter D | 28.346 in |
| Width B | 11.024 in |
| ISO bore code | 88 |
| Radial section height (D−d)/2 | 140 mm |
| Smallest bore in C4100-series | 100 mm |
| Largest outer diameter in C4100-series | 1090 mm |
| Width range across C4100-series | 65–412 mm |
| Bore position in C4100-series (smallest first) | 9 of 14 |
| Bore above smallest C4100-series size | 340 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C4188-MB | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 440×720×280 mm ISO 15 envelope and equivalent catalogue C/C0; C 4188 MB is the cylindrical-bore MB inner-ring-guided brass-caged execution of this size — boundary dimensions interchangeable, only mounting and cage execution differ. |
| 24188 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (440×720×280 mm) SKF spherical roller bearing SKF 24188 ECA/W33 with ratings within 10 % — not a drop-in substitute: SKF 24188 ECA/W33 locates the shaft axially while the CARB bearing must float; the two are designed to run as a locating/non-locating pair. |
| 24188-ECAK30-W33 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (440×720×280 mm) SKF spherical roller bearing SKF 24188 ECAK30/W33 with ratings within 10 % — not a drop-in substitute: SKF 24188 ECAK30/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 C4188-K30MB model number is decoded
SKF lists C 4188 K30MB in the dimension series 41 CARB toroidal roller bearings: the toroidal roller profile both follows tolerates angular misalignment and lets the inner ring slide axially inside the outer ring, giving free axial displacement at the non-locating position. Reading the code: C marks the CARB toroidal family, the first two digits (41) identify the ISO dimension series and the last two (88) encode the 440 mm bore; suffixes describe bore and execution. CARB bearings locate neither radially nor axially: the inner ring can walk axially inside the outer ring over the catalogue-listed axial-displacement range (s), so shaft thermal growth disappears as thrust rather than preloading the 440 mm seat. Selection arithmetic: C 7500 kN against C0 12900 kN gives a C0/C ratio of 1.72, and the 900 kN fatigue load limit Pu sets the contamination-adjusted life floor. Seat tolerances follow the ISO 15 recommendation for the heavy-loaded position — the 720 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
- thermal preloading when a shaft is located at both ends and growth has nowhere to go
- PA66 cage (TN9) softening when the sustained temperature passes the polymer limit
- electrical erosion of raceways on VFD-driven shafts without grounding or insulation
- 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 (471 kg here) — lifting gear and induction heating are mandatory, and a cocked ring scores the toroidal raceway before start-up.
- The quoted 7500/12900 kN ratings belong to this exact execution (C 4188 K30MB); 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.
- Tapered-bore K executions mount on adapter sleeves (1:12) and K30 on withdrawal sleeves (1:30) — the 440 mm bore changes the sleeve family, and the drive-up procedure differs accordingly.
- Reference and limiting speeds are different limits: the 500 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 7500/12900 kN ratings and 471000 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 4188 K30MB have?
A C 4188 K30MB measures 440 mm bore × 720 mm outside diameter × 280 mm width (17.323 × 28.346 × 11.024 in). From SKF catalogue PUB BU/P1 17000: dynamic C 7500 kN, static C0 12900 kN, fatigue limit Pu 900 kN, reference speed 500 r/min, limiting speed 670 r/min, mass about 471000 g.
What does C 4188 K30MB mean in SKF part numbering?
C marks CARB; 41 the dimension series; the size code gives 440 mm bore; K30MB is the execution (tapered 1:30 bore for withdrawal (AH) sleeve mounting, machined inner-ring-guided brass cage (MB)). The envelope follows ISO 15 and matches spherical roller bearing outlines, but the functions differ.
Why is C 4188 K30MB 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 4188 K30MB 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.