NU2311EA bearing: complete specifications & equivalents
The NU2311EA is a ISO 15 radial bearing sized 55 x 120 x 43 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 55 mm |
| Outer diameter D | 120 mm |
| Width B | 43 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 238 kN |
| Basic static load rating C0 | 233 kN |
| Fatigue load limit Pu | 28.4 kN |
| Limiting speed (mechanical) | 4700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2230 g |
| Manufacturer designation | NTN NU2311EA |
| 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 & NU2300-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 1.693 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 32.5 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) | 8 of 35 |
| Bore above smallest NU2300-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU2311EA | 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 NU2311EA model number is decoded
For pure radial duty on a 55 mm shaft NTN supplies NU2311EA: two integral ribs on the outer ring and a ribless, separable inner ring; the open execution is rated 4,700 r/min on grease and 6,700 r/min on oil. Digit by digit, NU2311EA reads as NU (outer ring ribbed, inner ring ribless), ISO 15 series, and bore 55 mm; trailing letters such as EA or E mark the cage/capacity execution and are part of the order number. NTN prints the raceway diameters for this size — Fw 70.5 mm and Ew 106.5 mm — the envelope inside the 55/120 mm bore/OD where the rollers actually run. Speed ratio check: limiting 4,700 r/min is .70 of the 6,700 r/min oil value for NU2311EA; grease-churn heating closes that gap as fill quantity rises. Housing and shaft fillets must clear the ring chamfers of NU2311EA; an oversized radius locks the ring on its face and tilts the 43 mm-wide seat.
Typical equipment & failure modes
Common applications
- industrial gearbox input and output shafts
- medium electric-motor and generator shafts
- pump and compressor crankshafts and rotors
- machine-tool gearbox and spindle radial sets
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
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- electrical pitting on VFD-driven motor shafts without grounding protection
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- On this 55 mm bore, shaft thermal growth can preload the inner ring if the fit is too tight; verify residual interference at temperature and confirm the float ring still slides after mounting NU2311EA.
- The 32.5 mm section at 55 mm bore leaves a narrow oil path; with the EA pressed-steel-cage cage the relubrication groove and oil-level design must keep grease from churning in the 43 mm-wide cavity.
- Open NU2311EA 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 55 mm contact.
- The NU rib arrangement is not interchangeable with another prefix on the same 55 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 120×43 mm envelope matches.
- The NU rib arrangement is not interchangeable with another prefix on the same 55 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 120×43 mm envelope matches.
- The 238/233 kN ratings, 28.4 kN Pu and 2230 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU2311EA (EA pressed-steel-cage 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 NU2311EA?
NU2311EA is an NTN NU single-row cylindrical roller bearing to ISO 15: 55 mm bore, 120 mm OD and 43 mm width (2.165 × 4.724 × 1.693 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 238 kN, C0 233 kN, Pu 28.4 kN, grease limiting speed 4,700 r/min, oil 6,700 r/min, mass about 2230 g. It is open, with the EA high-capacity 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. NU2311EA 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. This page's bearing carries the EA pressed-steel-cage execution.
Can NU2311EA 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 NU2311EA?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 70.5 mm, Ew 106.5 mm. The nominal bore/OD remain 55/120 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 4,700 r/min grease / 6,700 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.