NU238E bearing: complete specifications & equivalents
The NU238E is a ISO 15 radial bearing sized 190 x 340 x 55 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 190 mm |
| Outer diameter D | 340 mm |
| Width B | 55 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 770 kN |
| Basic static load rating C0 | 955 kN |
| Fatigue load limit Pu | 86.5 kN |
| Limiting speed (mechanical) | 1700 rpm |
| Operating temperature | -40 to +120 °C |
| Manufacturer designation | NTN NU238E |
| 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 | 7.48 in |
|---|---|
| Outer diameter D | 13.386 in |
| Width B | 2.165 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 75 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) | 29 of 36 |
| Bore above smallest NU200-series size | 175 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU238E | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
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 NU238E model number is decoded
NU238E is an NTN NU cylindrical roller bearing: two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially, inside the 190×340×55 mm ISO 15 envelope. On the NTN nameplate NU states which ring carries the ribs, which determines whether NU238E floats or locates; the numeric remainder is the ISO 15 series and 190 mm bore reference, not a fit or clearance instruction. With C 770 kN and C0 955 kN (C0/C ≈ 1.24) the bearing is proportioned for heavy radial load; the NU design carries no axial load and floats axially on both sides. Speed ratio check: limiting 1,700 r/min is .85 of the 2,000 r/min oil value for NU238E; 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 NU238E non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- rolling-mill work-roll and backup-roll positions
- large turbine and generator rotor bearings
- wind-turbine gearbox planet and rotor shafts
- ship propulsion line shafts and reduction gears
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
- rolling-contact fatigue after the catalogue L10 life is exceeded
- brinelling from static overload or impact during handling
Selection pitfalls — read before you substitute
- At 190 mm bore, oil-lubricated arrangements toward 2,000 r/min need positive flow and drain design; the NU238E ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The NU rib arrangement is not interchangeable with another prefix on the same 190 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 340×55 mm envelope matches.
- The NU rib arrangement is not interchangeable with another prefix on the same 190 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 340×55 mm envelope matches.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 770/955 kN pair here belongs to NU238E as printed, not to the bare size.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU238E skids at 1,700 r/min and fails by smearing long before L10 fatigue.
- The 770/955 kN ratings, 86.5 kN Pu are NTN Ball and Roller Bearings CAT.No.2203E values for NU238E (E high-capacity 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 NU238E?
NU238E is an NTN NU single-row cylindrical roller bearing to ISO 15: 190 mm bore, 340 mm OD and 55 mm width (7.48 × 13.386 × 2.165 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 770 kN, C0 955 kN, Pu 86.5 kN, grease limiting speed 1,700 r/min, oil 2,000 r/min. It is open, with the high-capacity pressed-steel cage of the E execution.
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. NU238E 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. NU238E is supplied in the standard open execution shown in the table.
Can NU238E 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 NU238E?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 230 mm. The nominal bore/OD remain 190/340 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 1,700 r/min grease / 2,000 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.