NU330 bearing: complete specifications & equivalents
The NU330 is a ISO 15 radial bearing sized 150 x 320 x 65 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 150 mm |
| Outer diameter D | 320 mm |
| Width B | 65 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 735 kN |
| Basic static load rating C0 | 805 kN |
| Fatigue load limit Pu | 76 kN |
| Limiting speed (mechanical) | 2100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 24700 g |
| Manufacturer designation | NTN NU330 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & NU300-series range
| Bore d | 5.906 in |
|---|---|
| Outer diameter D | 12.598 in |
| Width B | 2.559 in |
| ISO bore code | 30 |
| Radial section height (D−d)/2 | 85 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) | 24 of 34 |
| Bore above smallest NU300-series size | 133 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU330-ECM | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 150×320×65 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
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 NU330 model number is decoded
The NTN order number NU330 denotes a 150×320×65 mm (5.906 × 12.598 × 2.559 in) cylindrical roller bearing in the NU300 family, a pressed sheet-steel cage. The leading NU defines the rib arrangement (outer ring ribbed, inner ring ribless); the dimension-series digits and the two-digit bore code resolve to 150 mm, with 320 mm OD and 65 mm width from the ISO 15 general plan. With C 735 kN and C0 805 kN (C0/C ≈ 1.10) the bearing is proportioned for heavy radial load; the NU design carries no axial load and floats axially on both sides. Thermal planning around the 2,100 r/min grease ceiling should include the cage type (a pressed sheet-steel cage) and oil-flow option to 2,500 r/min for continuously high-duty 150 mm positions. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NU330 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- mining SAG/ball-mill drive shafts
- offshore drawworks and winch drums
- heavy press and large gearbox main shafts
- rolling-mill work-roll and backup-roll positions
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- false brinelling on standby machines exposed to external vibration
- hard-particle indentation of raceways in unfiltered oil or open arrangements
Selection pitfalls — read before you substitute
- At 150 mm bore, oil-lubricated arrangements toward 2,500 r/min need positive flow and drain design; the 24700 g NU330 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 735/805 kN pair here belongs to NU330 as printed, not to the bare size.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU330 skids at 2,100 r/min and fails by smearing long before L10 fatigue.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU330 skids at 2,100 r/min and fails by smearing long before L10 fatigue.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU330 skids at 2,100 r/min and fails by smearing long before L10 fatigue.
- The 735/805 kN ratings, 76 kN Pu and 24700 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU330 (standard execution); other makes sharing the ISO 15 envelope revise internal geometry without changing the order number, so keep the 2203E reference with the specification for critical drives.
Frequently asked questions
What are the dimensions and catalogue data of NU330?
NU330 is an NTN NU single-row cylindrical roller bearing to ISO 15: 150 mm bore, 320 mm OD and 65 mm width (5.906 × 12.598 × 2.559 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 735 kN, C0 805 kN, Pu 76 kN, grease limiting speed 2,100 r/min, oil 2,500 r/min, mass about 24700 g. It is open, with a pressed sheet-steel cage.
What is the difference between NU, NJ, NUP, N and NF cylindrical roller bearings?
The prefix states the rib arrangement: NU has two outer-ring ribs and a ribless inner ring (float, no axial load); NJ adds ribs for one-direction location; NUP adds a loose L-ring to locate both directions; N has two inner-ring ribs and a separable outer ring; NF has one rib per ring for one-direction guidance. NU330 is two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially.
What do the EA, E and ＊ suffixes mean on NTN cylindrical roller bearings?
EA is NTN's high-capacity design with a pressed sheet-steel cage and optimised roller complement in the same ISO 15 envelope; E marks the high-capacity design at the larger bores; the ＊ symbol printed before the code in the NTN catalogue marks the ULTAGE new-generation specification and is not typed as part of the order number. NU330 is supplied in the standard open execution shown in the table.
Can NU330 take axial load and locate a shaft?
the NU design carries no axial load and floats axially on both sides. Provide axial location with an adjacent locating bearing (angular-contact, deep-groove or a paired NJ/NUP set).
What do Fw and Ew mean for NU330?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 193 mm, Ew 277 mm. The nominal bore/OD remain 150/320 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,100 r/min grease / 2,500 r/min oil.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.