NU309EA bearing: complete specifications & equivalents
The NU309EA is a ISO 15 radial bearing sized 45 x 100 x 25 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 45 mm |
| Outer diameter D | 100 mm |
| Width B | 25 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 115 kN |
| Basic static load rating C0 | 98.5 kN |
| Fatigue load limit Pu | 12 kN |
| Limiting speed (mechanical) | 6500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 865 g |
| Manufacturer designation | NTN NU309EA |
| 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 | 1.772 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 0.984 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 27.5 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) | 7 of 34 |
| Bore above smallest NU300-series size | 28 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU309EA | 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 NU309EA model number is decoded
NU309EA 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 115 kN dynamic rating in the 45 mm bore. On the NTN nameplate NU states which ring carries the ribs, which determines whether NU309EA floats or locates; the numeric remainder is the ISO 15 series and 45 mm bore reference, not a fit or clearance instruction. NTN prints two speed ceilings: 6,500 r/min grease and 9,100 r/min oil — the pressed-steel cage and lubricant film set the real limit at the 45 mm bore. The 2.6 kN-per-mm-bore figure (115 kN over 45 mm) lets a NU309EA interchange candidate be screened quickly against the same-envelope ball or roller alternatives. Provide axial location with an adjacent locating bearing rather than expecting the float cylindrical set to hold thrust on the 45 mm shaft.
Typical equipment & failure modes
Common applications
- machine-tool gearbox and spindle radial sets
- material-handling drum and wheel shafts
- papermaking and printing auxiliary drives
- fan and blower rotor 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
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- brinelling from static overload or impact during handling
Selection pitfalls — read before you substitute
- On this 45 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 NU309EA.
- Do not replace NU309EA with a deep-groove ball bearing on rating alone: line contact gives 115 kN radial capacity but the bearing cannot carry the thrust duty a ball bearing can and misalignment tolerance is only 3–4 arc-minutes.
- The NU rib arrangement is not interchangeable with another prefix on the same 45 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 100×25 mm envelope matches.
- Open NU309EA 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 45 mm contact.
- If the shaft must be located both ways, do not use NU309EA alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- The 115/98.5 kN ratings, 12 kN Pu and 865 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU309EA (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 NU309EA?
NU309EA is an NTN NU single-row cylindrical roller bearing to ISO 15: 45 mm bore, 100 mm OD and 25 mm width (1.772 × 3.937 × 0.984 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 115 kN, C0 98.5 kN, Pu 12 kN, grease limiting speed 6,500 r/min, oil 9,100 r/min, mass about 865 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. NU309EA 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 NU309EA 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 NU309EA?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 58.5 mm, Ew 88.5 mm. The nominal bore/OD remain 45/100 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 6,500 r/min grease / 9,100 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.