NU18-800-ECMA bearing: complete specifications & equivalents
The NU18-800-ECMA is a ISO 15 radial bearing sized 800 x 980 x 82 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 800 mm |
| Outer diameter D | 980 mm |
| Width B | 82 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1720 kN |
| Basic static load rating C0 | 4150 kN |
| Fatigue load limit Pu | 190 kN |
| Reference speed (thermal) | 530 rpm |
| Limiting speed (mechanical) | 700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 137000 g |
| Manufacturer designation | SKF NU 18/800 ECMA |
| 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 & NU1800-series range
| Bore d | 31.496 in |
|---|---|
| Outer diameter D | 38.583 in |
| Width B | 3.228 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 90 mm |
| Smallest bore in NU1800-series | 380 mm |
| Largest outer diameter in NU1800-series | 1090 mm |
| Width range across NU1800-series | 46–85 mm |
| Bore position in NU1800-series (smallest first) | 5 of 6 |
| Bore above smallest NU1800-series size | 420 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NU18-800-ECMA model number is decoded
In SKF catalogue PUB BU/P1 17000, SKF NU 18/800 ECMA denotes a single-row caged cylindrical roller bearing on the ISO 15 800×980×82 mm envelope, dimension series 18 (ultra-slim section for large shafts), with catalogue mass 137000 g. 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 ECMA suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. The radial section height is 90.0 mm and the catalogue mass 137000 g; at 1720 kN dynamic rating this is roughly 2.15 kN of C per millimetre of bore before application factors. Fit practice for NU18-800-ECMA: 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
- marine propulsion line shafts
- heavy turbogenerator rotor supports
- mining hoist and winder shafts
- offshore drawworks shafts
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
- hard-particle indentation of the raceway in unfiltered oil systems
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 18 (ultra-slim section for large shafts) envelope is shared with the N/NU/NJ/NUP executions of 18/800, but flange configuration and axial-locating behaviour differ — quote the full SKF NU 18/800 ECMA 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 82 mm-wide ring and concentrates load.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 82 mm-wide ring and concentrates load.
- The 1720/4150 kN ratings are SKF catalogue 17000 (2018) values for the ECMA 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 NU18-800-ECMA?
SKF NU 18/800 ECMA is a single-row caged cylindrical roller bearing with 800 mm bore, 980 mm OD and 82 mm width per ISO 15. SKF lists C 1720 kN, C0 4150 kN, Pu 190 kN, reference speed 530 r/min and limiting speed 700 r/min, mass about 137000 g.
What does the NU designation and ECMA suffix mean?
The ECMA suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. 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 NU18-800-ECMA 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 NU18-800-ECMA 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.