NU315 bearing: complete specifications & equivalents
The NU315 is a ISO 15 radial bearing sized 75 x 160 x 37 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 75 mm |
| Outer diameter D | 160 mm |
| Width B | 37 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 280 kN |
| Basic static load rating C0 | 265 kN |
| Fatigue load limit Pu | 33.5 kN |
| Reference speed (thermal) | 4500 rpm |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3300 g |
| Manufacturer designation | NU 315 ECP |
| 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 & NU300-series range
| Bore d | 2.953 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 1.457 in |
| ISO bore code | 15 |
| Radial section height (D−d)/2 | 42.5 mm |
| Smallest bore in NU300-series | 17 mm |
| Largest outer diameter in NU300-series | 620 mm |
| Width range across NU300-series | 14–109 mm |
| Bore position in NU300-series (smallest first) | 13 of 34 |
| Bore above smallest NU300-series size | 58 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU315-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 75×160×37 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| 6315 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Identical envelope but a different bearing type — confirm load and speed suitability before substitution. |
| 6315-2RS | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Identical envelope but a different bearing type — confirm load and speed suitability before substitution. |
| 6315-ZZ | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Identical envelope but a different bearing type — confirm load and speed suitability before substitution. |
| N315-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 boundary envelope and equivalent catalogue ratings; SKF N 315 ECP is a different execution with its own cage/flange configuration. |
| NJ315-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 boundary envelope and equivalent catalogue ratings; SKF NJ 315 ECP is a different execution with its own cage/flange configuration. |
| NUP315-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 boundary envelope and equivalent catalogue ratings; SKF NUP 315 ECP is a different execution with its own cage/flange configuration. |
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 NU315 model number is decoded
For a 75 mm shaft carrying pure radial load, SKF lists NU315 under catalogue execution NU 315 ECP: one open single-row cylindrical roller bearing with polymer cage and separable inner ring. Digit by digit, NU315 reads as bearing type NU (single-row, inner ring separable), standard series 3, and bore reference 15 resolving to 75 mm; 160 mm OD and 37 mm width are the matching ISO 15 boundary values. The SKF catalogue adds the ECP suffix for the standard glass-fibre reinforced polyamide cage; ECJ (pressed steel) and ECM (machined brass) are alternative executions with different speed and temperature ratings. The 33.5 kN Pu figure feeds the adjusted-life equation at contaminated or partial-film conditions, and the 0.95 C0/C balance shows this execution is tuned to heavy radial loads rather than mixed radial-plus-axial duty. When press-fitting the inner ring, support the ring face squarely; cocking the ring over a keyway or burr brinells the raceway and shows as vibration within the first running hours.
Typical equipment & failure modes
Common applications
- wind-turbine gearbox intermediate shafts
- marine propulsion gearbox shafts
- heavy industrial gearbox shafts
- large pump and turbine 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 skidding at insufficient radial load or during start-up before oil film build-up
- roller-end scoring from inadequate oil flow in the roller-raceway contact
- hard-particle indentation of the raceway in unfiltered oil systems
Selection pitfalls — read before you substitute
- Mount the 75 mm bore NU315 by induction heating of the inner ring (max 120 °C — the polymer cage sets the ceiling, not the steel); driving it home through the rollers brinells the raceway.
- The NU300 series at 75 mm bore (160×37 mm) is the standard-section cylindrical roller envelope; stepping to a wide-section 22/23 variant changes OD, width and heat generation — it is not a drop-in swap when the housing and speed are fixed.
- The NU315 shares its ISO 15 envelope with other cylindrical bearings of the same code but is not a drop-in replacement for a ball bearing: it has no axial load capacity in the NU design, and a deep-groove bearing cannot replace its radial-capacity duty.
- The ECP polymer cage is rated for standard industrial service up to 120 °C; sustained running above the limiting speed or with degraded lubricant softens the cage — inspect at every relubrication interval.
- The 280/265 kN ratings are SKF catalogue 17000 values for the ECP polymer-cage execution; SKF can revise internal geometry without changing the order number, so keep the catalogue version (PUB BU/P1 17000/1 EN, 2018) with the specification and re-verify for critical drives.
- SKF lists several executions of NU315 (ECP polymer cage, ECJ pressed steel, ECM machined brass); they are not interchangeable order numbers — quote the full NU 315 ECP designation when purchasing and match the execution to the speed and temperature requirements.
Frequently asked questions
What are the dimensions and catalogue data of NU315?
The NU 315 ECP is a single-row cylindrical roller bearing with 75 mm bore, 160 mm outer diameter and 37 mm width (2.953 × 6.299 × 1.457 in) per ISO 15. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 280 kN, C0 265 kN, fatigue load limit Pu 33.5 kN, reference speed 4,500 r/min, limiting speed 5,300 r/min, mass about 3300 g. It is an open, separable bearing with a glass-fibre reinforced polyamide cage.
How does the NU315 bore code work?
The last two digits of NU315 are bore code 15, so 15 × 5 = 75 mm bore. The 160 mm OD and 37 mm width come from the ISO 15 dimension-series plan, shared with other cylindrical bearings of the same code.
What does the ECP suffix mean on NU315?
ECP stands for a glass-fibre reinforced polyamide cage (PA66), the SKF standard for this size. Alternative executions include ECJ (pressed steel cage) and ECM (machined brass cage), which have different speed and temperature ratings and are separate order numbers.
Can NU315 take axial load?
No — the NU design has no ribs on the outer ring and cannot support axial load in either direction. It is intended for pure radial load with axial location provided by adjacent components. If axial location is required, consider NJ (one-direction) or NUP (two-direction) variants, or pair the NU bearing with a thrust or angular-contact bearing.
How does NU315 compare with a ball bearing of the same bore?
A cylindrical roller bearing has line contact and much higher radial capacity than a ball bearing of the same bore, but it cannot take axial load in the NU design and is sensitive to misalignment (≈ 3–4 minutes of arc). Speed limits are generally lower than deep-groove ball bearings. A ball bearing cannot be dropped into a pure radial cylindrical-roller position without re-checking life and deflection, and vice versa.
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.