NU305EA bearing: complete specifications & equivalents
The NU305EA is a ISO 15 radial bearing sized 25 x 62 x 17 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 25 mm |
| Outer diameter D | 62 mm |
| Width B | 17 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 49 kN |
| Basic static load rating C0 | 37.5 kN |
| Fatigue load limit Pu | 4.55 kN |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 242 g |
| Manufacturer designation | NTN NU305EA |
| 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 | 0.984 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 0.669 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 18.5 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) | 3 of 34 |
| Bore above smallest NU300-series size | 8 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU305EA | 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 NU305EA model number is decoded
NU305EA is the standard section of the NTN NU300 dimension series for a 25 mm shaft — 49 kN of basic dynamic capacity in a 242 g, open bearing. Numbering ties NU305EA to its envelope: type code NU, series NU300, 25 mm bore; the 62×17 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. With C 49 kN and C0 37.5 kN (C0/C ≈ 0.77) the bearing is proportioned for heavy radial load; the NU design carries no axial load and floats axially on both sides. Thermal planning around the 11,000 r/min grease ceiling should include the cage type (the EA high-capacity pressed sheet-steel cage) and oil-flow option to 15,600 r/min for continuously high-duty 25 mm positions. Mount the separable inner ring + roller assembly on the shaft first and slide the outer ring into the housing; never press the outer ring through the rollers of NU305EA.
Typical equipment & failure modes
Common applications
- small pump and compressor rotor shafts
- appliance and office-machine drives
- agricultural PTO and implement gear shafts
- small conveyor and fan rotor positions
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- 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
- brinelling from static overload or impact during handling
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- Small 25 mm-bore cylindrical rollers are skid-sensitive: ensure the radial load exceeds the minimum-load floor at operating speed, or the NU305EA rollers smear even with correct grease.
- The 18.5 mm section at 25 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 17 mm-wide cavity.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 49/37.5 kN pair here belongs to NU305EA as printed, not to the bare size.
- If the shaft must be located both ways, do not use NU305EA alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU305EA skids at 11,000 r/min and fails by smearing long before L10 fatigue.
- The 49/37.5 kN ratings, 4.55 kN Pu and 242 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU305EA (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 NU305EA?
NU305EA is an NTN NU single-row cylindrical roller bearing to ISO 15: 25 mm bore, 62 mm OD and 17 mm width (0.984 × 2.441 × 0.669 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 49 kN, C0 37.5 kN, Pu 4.55 kN, grease limiting speed 11,000 r/min, oil 15,600 r/min, mass about 242 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. NU305EA 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 NU305EA 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 NU305EA?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 34 mm, Ew 54 mm. The nominal bore/OD remain 25/62 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 11,000 r/min grease / 15,600 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.