NU405 bearing: complete specifications & equivalents
The NU405 is a ISO 15 radial bearing sized 25 x 80 x 21 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 | 80 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 51.5 kN |
| Basic static load rating C0 | 40 kN |
| Fatigue load limit Pu | 4.85 kN |
| Limiting speed (mechanical) | 8500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 536 g |
| Manufacturer designation | NTN NU405 |
| 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 & NU400-series range
| Bore d | 0.984 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.827 in |
| ISO bore code | 05 |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in NU400-series | 25 mm |
| Largest outer diameter in NU400-series | 310 mm |
| Width range across NU400-series | 21–72 mm |
| Bore position in NU400-series (smallest first) | 1 of 17 |
| Bore above smallest NU400-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU405 | 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 NU405 model number is decoded
NU405 is the heavy (04) section of the NTN NU400 dimension series for a 25 mm shaft — 51.5 kN of basic dynamic capacity in a 536 g, open bearing. Digit by digit, NU405 reads as NU (outer ring ribbed, inner ring ribless), ISO 15 series, and bore 25 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 38.8 mm and Ew 62.8 mm — the envelope inside the 25/80 mm bore/OD where the rollers actually run. The 25 mm (0.984 in) bore and 80 mm (3.15 in) OD are ISO 15 boundary values; fillet and shoulder dimensions must still come from the NTN mounting table for the 21 mm-wide ring. Housing and shaft fillets must clear the ring chamfers of NU405; an oversized radius locks the ring on its face and tilts the 21 mm-wide seat.
Typical equipment & failure modes
Common applications
- two-wheeler and small-engine transmission shafts
- small pump and compressor rotor shafts
- appliance and office-machine drives
- agricultural PTO and implement gear shafts
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
- false brinelling on standby machines exposed to external vibration
- fretting corrosion on a loose rotating shaft seat
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 NU405 rollers smear even with correct grease.
- Open NU405 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 25 mm contact.
- Do not replace NU405 with a deep-groove ball bearing on rating alone: line contact gives 51.5 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 21 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 25 mm inner ring.
- The NU rib arrangement is not interchangeable with another prefix on the same 25 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 80×21 mm envelope matches.
- The 51.5/40 kN ratings, 4.85 kN Pu and 536 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU405 (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 NU405?
NU405 is an NTN NU single-row cylindrical roller bearing to ISO 15: 25 mm bore, 80 mm OD and 21 mm width (0.984 × 3.15 × 0.827 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 51.5 kN, C0 40 kN, Pu 4.85 kN, grease limiting speed 8,500 r/min, oil 10,000 r/min, mass about 536 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. NU405 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. NU405 is supplied in the standard open execution shown in the table.
Can NU405 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 NU405?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 38.8 mm, Ew 62.8 mm. The nominal bore/OD remain 25/80 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 8,500 r/min grease / 10,000 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.