NU12-500-MA bearing: complete specifications & equivalents
The NU12-500-MA is a ISO 15 radial bearing sized 500 x 920 x 185 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 | 920 mm |
| Width B | 185 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 5280 kN |
| Basic static load rating C0 | 8500 kN |
| Fatigue load limit Pu | 620 kN |
| Reference speed (thermal) | 670 rpm |
| Limiting speed (mechanical) | 950 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 575000 g |
| Manufacturer designation | SKF NU 12/500 MA |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical 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 & NU1200-series range
| Bore d | 19.685 in |
|---|---|
| Outer diameter D | 36.22 in |
| Width B | 7.283 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 210 mm |
| Smallest bore in NU1200-series | 460 mm |
| Largest outer diameter in NU1200-series | 1030 mm |
| Width range across NU1200-series | 165–206 mm |
| Bore position in NU1200-series (smallest first) | 2 of 3 |
| Bore above smallest NU1200-series size | 40 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NU12-500-MA model number is decoded
Ordering number SKF NU 12/500 MA resolves to a 500×920×185 mm single-row caged cylindrical roller bearing (dimension series 12 (extra-slim OD, wide)); two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable. Reading the NU prefix: two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable. This makes the execution non-locating: the inner ring assembly can float axially in both directions and the bearing cannot support axial load. The MA suffix marks the basic (non-E) execution with a machined brass cage, the standard choice for the larger and earlier-design sizes. With C 5280 kN and C0 8500 kN, size the bearing on the 500×920 mm ISO 15 envelope and check the 620 kN Pu against the equivalent-load floor; the catalogue lists 670 r/min thermal reference speed and 950 r/min mechanical limiting speed. Fit practice for NU12-500-MA: fit the inner ring and roller assembly onto the shaft and the outer ring into the housing independently; thermal expansion is absorbed by axial float, so do not trap the inner ring between shaft shoulders. Single-row cylindrical rollers tolerate only about 3–4 minutes of arc misalignment, so verify shaft and housing alignment.
Typical equipment & failure modes
Common applications
- heavy turbogenerator rotor supports
- mining hoist and winder shafts
- offshore drawworks shafts
- large rolling-mill drive trains
Known failure patterns
- inner-ring raceway spalling from overload or contamination in the line-contact hertz zone
- outer-ring raceway fatigue after extended service at loads above the catalogue L10 rating
- cage pocket wear from roller skew at light load
- polymer cage cracking or softening after sustained running above 120 °C or with incompatible lubricant
- surface distress (micro-pitting) when the EHL film falls below the composite roughness at high specific load
- edge-loading fatigue after shaft deflection beyond the 3–4 minute alignment limit
- electrical pitting on VFD-driven shafts without grounding protection
Selection pitfalls — read before you substitute
- Do not use a NU bearing where axial load must be carried — the design carries radial load only
- The dimension series 12 (extra-slim OD, wide) envelope is shared with the N/NU/NJ/NUP executions of 12/500, but flange configuration and axial-locating behaviour differ — quote the full SKF NU 12/500 MA and do not substitute rib styles without checking the shaft locating scheme.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 185 mm-wide ring and concentrates load.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 185 mm-wide ring and concentrates load.
- The 5280/8500 kN ratings are SKF catalogue 17000 (2018) values for the MA execution; re-verify against the current catalogue for critical drives and keep the catalogue version with the specification.
Frequently asked questions
What are the dimensions and catalogue data of NU12-500-MA?
SKF NU 12/500 MA is a single-row caged cylindrical roller bearing with 500 mm bore, 920 mm OD and 185 mm width per ISO 15. SKF lists C 5280 kN, C0 8500 kN, Pu 620 kN, reference speed 670 r/min and limiting speed 950 r/min, mass about 575000 g.
What does the NU designation and MA suffix mean?
The MA suffix marks the basic (non-E) execution with a machined brass cage, the standard choice for the larger and earlier-design sizes. Structurally this execution has two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable.
Can NU12-500-MA take axial load and locate the shaft?
No — the inner ring has no flanges, so the NU bearing is non-locating and carries radial load only; use NJ (one direction), NUP (both directions) or a paired thrust bearing for axial duty.
How does NU12-500-MA compare with the other executions in the same envelope?
The N/NU/NJ/NUP executions share the ISO 15 envelope and load ratings but differ in flange arrangement and axial-locating behaviour; quote the exact order number.
What limits the service life of this bearing most often?
Line-contact fatigue above the L10 rating, cage wear at light loads and high temperatures, and edge loading from misalignment beyond about 3–4 minutes of arc are the typical failure drivers.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings on 2026-09-26. Read our editorial & correction policy.