NU2306 bearing: complete specifications & equivalents
The NU2306 is a ISO 15 radial bearing sized 30 x 72 x 27 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 30 mm |
| Outer diameter D | 72 mm |
| Width B | 27 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 83 kN |
| Basic static load rating C0 | 75 kN |
| Fatigue load limit Pu | 9.65 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 12000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 530 g |
| Manufacturer designation | NU 2306 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 & NU2300-series range
| Bore d | 1.181 in |
|---|---|
| Outer diameter D | 2.835 in |
| Width B | 1.063 in |
| ISO bore code | 06 |
| Radial section height (D−d)/2 | 21 mm |
| Smallest bore in NU2300-series | 20 mm |
| Largest outer diameter in NU2300-series | 750 mm |
| Width range across NU2300-series | 21–224 mm |
| Bore position in NU2300-series (smallest first) | 3 of 35 |
| Bore above smallest NU2300-series size | 10 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ2306-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 boundary envelope and equivalent catalogue ratings; SKF NJ 2306 ECP is a different execution with its own cage/flange configuration. |
| NUP2306-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 boundary envelope and equivalent catalogue ratings; SKF NUP 2306 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 NU2306 model number is decoded
NU 2306 ECP belongs to the SKF single-row cylindrical roller range — the 30 mm bore entry in the NU2300 series, dimensioned 72 mm OD and 27 mm wide to the ISO 15 boundary plan. Digit by digit, NU2306 reads as bearing type NU (single-row, inner ring separable), wide series 23, and bore reference 06 resolving to 30 mm; 72 mm OD and 27 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. Catalogue mass 530 g for the 30×72×27 mm open execution covers the polymer cage and standard roller complement; steel or brass cage variants differ slightly in mass and carry their own order numbers. 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
- paper-machine wet-section rolls
- rolling-mill auxiliary gear trains
- crane hoist and trolley wheel shafts
- industrial gearbox input/output 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
- 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
- brinelling from static overload or impact during handling and mounting
Selection pitfalls — read before you substitute
- On this 30 mm bore, thermal expansion of the shaft can preload the inner ring if the fit is too tight; calculate the residual interference at operating temperature and confirm the outer ring can still slide axially in the housing.
- The NU2300 series at 30 mm bore (72×27 mm) is the wide-section cylindrical roller with higher capacity but lower speed limit than the standard NU300 counterpart; do not substitute without re-checking shaft shoulder diameters and dn limit.
- Never press the outer ring through the roller complement during fitting: force for a press fit goes through the ring faces only, or brinell marks on the 72 mm race release as noise within the first running hours.
- The 530 g mass and 27 mm width mean abutment faces must be square to the axis within the bearing's own P0 tolerance; a tilted spacer tilts the outer ring and concentrates load on one roller row of NU2306.
- The 83/75 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 NU2306 (ECP polymer cage, ECJ pressed steel, ECM machined brass); they are not interchangeable order numbers — quote the full NU 2306 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 NU2306?
The NU 2306 ECP is a single-row cylindrical roller bearing with 30 mm bore, 72 mm outer diameter and 27 mm width (1.181 × 2.835 × 1.063 in) per ISO 15. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 83 kN, C0 75 kN, fatigue load limit Pu 9.65 kN, reference speed 11,000 r/min, limiting speed 12,000 r/min, mass about 530 g. It is an open, separable bearing with a glass-fibre reinforced polyamide cage.
How does the NU2306 bore code work?
The last two digits of NU2306 are bore code 06, so 06 × 5 = 30 mm bore. The 72 mm OD and 27 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 NU2306?
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 NU2306 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 NU2306 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.