NU208-NTN bearing: complete specifications & equivalents
The NU208-NTN is a ISO 15 radial bearing sized 40 x 80 x 18 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 | 80 mm |
| Width B | 18 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 48.5 kN |
| Basic static load rating C0 | 43 kN |
| Fatigue load limit Pu | 5.25 kN |
| Limiting speed (mechanical) | 9400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 370 g |
| Manufacturer designation | NTN NU208 |
| 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 & NU200-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.709 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 20 mm |
| Smallest bore in NU200-series | 15 mm |
| Largest outer diameter in NU200-series | 580 mm |
| Width range across NU200-series | 11–92 mm |
| Bore position in NU200-series (smallest first) | 7 of 36 |
| Bore above smallest NU200-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU208 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×80×18 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 NU208-NTN model number is decoded
NTN lists NU208 on the 40×80 mm envelope, 18 mm wide: a line-contact radial bearing with a pressed sheet-steel cage and a grease limiting speed of 9,400 r/min. Digit by digit, NU208 reads as NU (outer ring ribbed, inner ring ribless), ISO 15 series, and bore 40 mm; trailing letters such as EA or E mark the cage/capacity execution and are part of the order number. NTN ships these bearings open with normal (CN) radial clearance and P0 tolerance as standard; precision classes and C3/C4 clearance are separate order suffixes, not part of NU208. Rating life at 48.5 kN C assumes clean oil and adequate film; the 5.25 kN Pu floor means contamination derating — not the C rating alone — governs adjusted life in dusty gearboxes. On NU arrangements confirm which ring is separable before heating: forcing the ribbed ring off over the roller complement damages the cage and rib faces.
Typical equipment & failure modes
Common applications
- fan and blower rotor positions
- industrial gearbox input and output shafts
- medium electric-motor and generator shafts
- pump and compressor crankshafts and rotors
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- cage distortion after a mounting blow carried through the roller set
- grease starvation and cage drag when relubrication intervals are extended past the grease life
- fretting corrosion on a loose rotating shaft seat
- false brinelling on standby machines exposed to external vibration
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 NU208.
- If the shaft must be located both ways, do not use NU208 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 NU208 skids at 9,400 r/min and fails by smearing long before L10 fatigue.
- If the shaft must be located both ways, do not use NU208 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 80 mm race brinells and releases as vibration within hours.
- The 48.5/43 kN ratings, 5.25 kN Pu and 370 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU208 (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 NU208?
NU208 is an NTN NU single-row cylindrical roller bearing to ISO 15: 40 mm bore, 80 mm OD and 18 mm width (1.575 × 3.15 × 0.709 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 48.5 kN, C0 43 kN, Pu 5.25 kN, grease limiting speed 9,400 r/min, oil 11,000 r/min, mass about 370 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. NU208 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. NU208 is listed among the ＊ ULTAGE-marked executions in 2203E.
Can NU208 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 NU208?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 50 mm, Ew 70 mm. The nominal bore/OD remain 40/80 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 9,400 r/min grease / 11,000 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.