NU230 bearing: complete specifications & equivalents
The NU230 is a ISO 15 radial bearing sized 150 x 270 x 45 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 | 270 mm |
| Width B | 45 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 380 kN |
| Basic static load rating C0 | 435 kN |
| Fatigue load limit Pu | 42.5 kN |
| Limiting speed (mechanical) | 2500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 9720 g |
| Manufacturer designation | NTN NU230 |
| 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 & NU200-series range
| Bore d | 5.906 in |
|---|---|
| Outer diameter D | 10.63 in |
| Width B | 1.772 in |
| ISO bore code | 30 |
| Radial section height (D−d)/2 | 60 mm |
| Smallest bore in NU200-series | 15 mm |
| Largest outer diameter in NU200-series | 580 mm |
| Width range across NU200-series | 11–92 mm |
| Bore position in NU200-series (smallest first) | 25 of 36 |
| Bore above smallest NU200-series size | 135 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU230-ECM | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 150×270×45 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 NU230 model number is decoded
NU230 is the standard section of the NTN NU200 dimension series for a 150 mm shaft — 380 kN of basic dynamic capacity in a 9720 g, open bearing. Digit by digit, NU230 reads as NU (outer ring ribbed, inner ring ribless), ISO 15 series, and bore 150 mm; trailing letters such as EA or E mark the cage/capacity execution and are part of the order number. NTN prints two speed ceilings: 2,500 r/min grease and 2,900 r/min oil — the pressed-steel cage and lubricant film set the real limit at the 150 mm bore. Speed ratio check: limiting 2,500 r/min is .86 of the 2,900 r/min oil value for NU230; grease-churn heating closes that gap as fill quantity rises. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NU230 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- offshore drawworks and winch drums
- heavy press and large gearbox main shafts
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- cage wear accelerated when the EA high-capacity roller complement runs continuously above its thermal balance
- roller-end and raceway scoring from inadequate oil flow under heavy radial load
- fretting corrosion on a loose rotating shaft seat
- electrical pitting on VFD-driven motor shafts without grounding protection
Selection pitfalls — read before you substitute
- At 150 mm bore, oil-lubricated arrangements toward 2,900 r/min need positive flow and drain design; the 9720 g NU230 ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 270 mm race brinells and releases as vibration within hours.
- Open NU230 units need application-supplied sealing and a defined lubricant schedule; film thickness is the first failure mode for line contact when viscosity drops at the 150 mm contact.
- Wide (22/23) and light (10/49) executions at 150 mm bore share bore but not OD/width; check the full NU200 series code before substituting, because housing and shoulder geometry will not interchange.
- If the shaft must be located both ways, do not use NU230 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- The 380/435 kN ratings, 42.5 kN Pu and 9720 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU230 (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 NU230?
NU230 is an NTN NU single-row cylindrical roller bearing to ISO 15: 150 mm bore, 270 mm OD and 45 mm width (5.906 × 10.63 × 1.772 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 380 kN, C0 435 kN, Pu 42.5 kN, grease limiting speed 2,500 r/min, oil 2,900 r/min, mass about 9720 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. NU230 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. NU230 is supplied in the standard open execution shown in the table.
Can NU230 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 NU230?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 182 mm, Ew 238 mm. The nominal bore/OD remain 150/270 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 2,500 r/min grease / 2,900 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.