C31-710-MB bearing: complete specifications & equivalents
The C31-710-MB is a ISO 15 radial bearing sized 710 x 1150 x 345 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 710 mm |
| Outer diameter D | 1150 mm |
| Width B | 345 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 13400 kN |
| Basic static load rating C0 | 25500 kN |
| Fatigue load limit Pu | 1530 kN |
| Reference speed (thermal) | 340 rpm |
| Limiting speed (mechanical) | 480 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1470000 g |
| Manufacturer designation | C 31/710 MB |
| 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 | 27.953 in |
|---|---|
| Outer diameter D | 45.276 in |
| Width B | 13.583 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 220 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) | 26 of 28 |
| Bore above smallest C3100-series size | 610 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C31-710-KMB | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 710×1150×345 mm ISO 15 envelope and equivalent catalogue C/C0; C 31/710 KMB is the 1:12 tapered-bore K MB inner-ring-guided 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 C31-710-MB model number is decoded
For long shafts that grow thermally, SKF supplies C 31/710 MB: the toroidal rollers allow the 710 mm inner ring to displace axially without induced thrust, while still accommodating shaft deflection like a spherical bearing. SKF builds the CARB order number from size plus execution: the bare number C 31/710 is the brass-caged cylindrical-bore bearing, K (or K30) makes the bore tapered for sleeve mounting, and the cage/seal letters follow — here MB. 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 710 mm seat. Speed planning separates the 340 r/min thermal reference from the 480 r/min mechanical limiting speed. The full-complement V executions carry more load but list no thermal reference speed; the brass-caged executions run faster and cooler at light load. Seat tolerances follow the ISO 15 recommendation for the heavy-loaded position — the 1150 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
- winder and reel drums in paper and steel strip plants
- paper machine drying cylinders and calender rolls with long, thermally expanding shafts
- continuous-caster guide rolls and slab-caster segments under heat growth
- vibrating screen exciters fitted with the VE240 tolerance execution
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
- At 710 mm bore the 1470 kg mass and 345 mm width make seating geometry dominant: sphered-washer seats and oil flow must be verified in place, not just on the drawing.
- Tapered-bore K executions mount on adapter sleeves (1:12) and K30 on withdrawal sleeves (1:30) — the 710 mm bore changes the sleeve family, and the drive-up procedure differs accordingly.
- Reference and limiting speeds are different limits: the 340 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.
- Never use C 31/710 MB 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 quoted 13400/25500 kN ratings belong to this exact execution (C 31/710 MB); VE240 vibrating-screen variants and sealed 2CS/2NS variants have their own figures even at the same envelope.
- The 13400/25500 kN ratings and 1470000 g mass are SKF catalogue values transcribed from ch. 10.1 of PUB BU/P1 17000 (PDF table page 868); 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
Why is C 31/710 MB 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 31/710 MB 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.
Which dimensions does the C 31/710 MB have?
A C 31/710 MB measures 710 mm bore × 1150 mm outside diameter × 345 mm width (27.953 × 45.276 × 13.583 in). From SKF catalogue PUB BU/P1 17000: dynamic C 13400 kN, static C0 25500 kN, fatigue limit Pu 1530 kN, reference speed 340 r/min, limiting speed 480 r/min, mass about 1470000 g.
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.