NU2311-NTN bearing: complete specifications & equivalents
The NU2311-NTN 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 |
| Basic dynamic load rating C | 164 kN |
| Basic static load rating C0 | 162 kN |
| Fatigue load limit Pu | 19.8 kN |
| Limiting speed (mechanical) | 5200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2130 g |
| Manufacturer designation | NTN NU2311 |
| 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 | 11 |
| 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 |
|---|---|---|---|
| NU2311 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×120×43 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 NU2311-NTN model number is decoded
NU2311 belongs to the NTN cylindrical roller range in NTN Ball and Roller Bearings CAT.No.2203E, under the ＊ ULTAGE new-generation specification: line-contact rollers between ground raceways for a 164 kN dynamic rating in the 55 mm bore. Digit by digit, NU2311 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. Line contact between rollers and raceways gives NU2311 high radial capacity but no tolerance for misalignment: beyond roughly 3–4 arc-minutes the roller ends edge-load and fatigue accelerates. Equivalent-load planning treats NU2311 as a pure radial bearing: keep P below 164 kN at the required L10, and let a paired angular-contact or thrust part carry any sustained axial component. After mounting verify the outer ring slides axially by hand at ambient temperature; a stuck float ring in a NU2311 non-locating position preloads the bearing when the shaft grows.
Typical equipment & failure modes
Common applications
- medium electric-motor and generator shafts
- pump and compressor crankshafts and rotors
- machine-tool gearbox and spindle radial sets
- material-handling drum and wheel shafts
Known failure patterns
- inner-ring raceway spalling from overload in the line-contact Hertzian zone
- cage wear accelerated when the EA high-capacity roller complement runs continuously above its thermal balance
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- electrical pitting on VFD-driven motor shafts without grounding protection
- brinelling from static overload or impact during handling
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 NU2311.
- The 43 mm width and abutment faces must be square to the axis; a tilted spacer concentrates load across the roller set and shows as uneven raceway polish on the 55 mm inner ring.
- If the shaft must be located both ways, do not use NU2311 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- Open NU2311 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.
- Wide (22/23) and light (10/49) executions at 55 mm bore share bore but not OD/width; check the full NU2300 series code before substituting, because housing and shoulder geometry will not interchange.
- The 164/162 kN ratings, 19.8 kN Pu and 2130 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU2311 (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 NU2311?
NU2311 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 164 kN, C0 162 kN, Pu 19.8 kN, grease limiting speed 5,200 r/min, oil 6,100 r/min, mass about 2130 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. NU2311 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. NU2311 is listed among the ＊ ULTAGE-marked executions in 2203E.
Can NU2311 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 NU2311?
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 104.5 mm. The nominal bore/OD remain 55/120 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 5,200 r/min grease / 6,100 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.