NU308EA bearing: complete specifications & equivalents
The NU308EA is a ISO 15 radial bearing sized 40 x 90 x 23 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 40 mm |
| Outer diameter D | 90 mm |
| Width B | 23 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 98.5 kN |
| Basic static load rating C0 | 81.5 kN |
| Fatigue load limit Pu | 9.95 kN |
| Limiting speed (mechanical) | 7200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 658 g |
| Manufacturer designation | NTN NU308EA |
| 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 | 1.575 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 0.906 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 25 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) | 6 of 34 |
| Bore above smallest NU300-series size | 23 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU308EA | 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 NU308EA model number is decoded
For pure radial duty on a 40 mm shaft NTN supplies NU308EA: two integral ribs on the outer ring and a ribless, separable inner ring; the open execution is rated 7,200 r/min on grease and 10,200 r/min on oil. Numbering ties NU308EA to its envelope: type code NU, series NU300, 40 mm bore; the 90×23 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. The 25.0 mm radial section ((90−40)/2) frames the roller complement; capacity per millimetre of bore is about 2.5 kN/mm before application factors. Rating life at 98.5 kN C assumes clean oil and adequate film; the 9.95 kN Pu floor means contamination derating — not the C rating alone — governs adjusted life in dusty gearboxes. Provide axial location with an adjacent locating bearing rather than expecting the float cylindrical set to hold thrust on the 40 mm shaft.
Typical equipment & failure modes
Common applications
- material-handling drum and wheel shafts
- papermaking and printing auxiliary drives
- fan and blower rotor positions
- industrial gearbox input and output shafts
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
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- On this 40 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 NU308EA.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 98.5/81.5 kN pair here belongs to NU308EA as printed, not to the bare size.
- Wide (22/23) and light (10/49) executions at 40 mm bore share bore but not OD/width; check the full NU300 series code before substituting, because housing and shoulder geometry will not interchange.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 90 mm race brinells and releases as vibration within hours.
- The 25.0 mm section at 40 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 23 mm-wide cavity.
- The 98.5/81.5 kN ratings, 9.95 kN Pu and 658 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU308EA (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 NU308EA?
NU308EA is an NTN NU single-row cylindrical roller bearing to ISO 15: 40 mm bore, 90 mm OD and 23 mm width (1.575 × 3.543 × 0.906 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 98.5 kN, C0 81.5 kN, Pu 9.95 kN, grease limiting speed 7,200 r/min, oil 10,200 r/min, mass about 658 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. NU308EA 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 NU308EA 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 NU308EA?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 52 mm, Ew 80 mm. The nominal bore/OD remain 40/90 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 7,200 r/min grease / 10,200 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.