NJ208 bearing: complete specifications & equivalents
The NJ208 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 NJ208 |
| 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 & NJ200-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 NJ200-series | 15 mm |
| Largest outer diameter in NJ200-series | 580 mm |
| Width range across NJ200-series | 11–92 mm |
| Bore position in NJ200-series (smallest first) | 7 of 36 |
| Bore above smallest NJ200-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ208-ECP | 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 NJ208 model number is decoded
NJ208 is the standard section of the NTN NJ200 dimension series for a 40 mm shaft — 48.5 kN of basic dynamic capacity in a 370 g, open bearing. The leading NJ defines the rib arrangement (inner ring two ribs + one outer rib); the dimension-series digits and the two-digit bore code resolve to 40 mm, with 80 mm OD and 18 mm width from the ISO 15 general plan. 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 NJ208. Speed ratio check: limiting 9,400 r/min is .85 of the 11,000 r/min oil value for NJ208; grease-churn heating closes that gap as fill quantity rises. On NJ 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
- 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
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- hard-particle indentation of raceways in unfiltered oil or open arrangements
- rolling-contact fatigue after the catalogue L10 life is exceeded
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 NJ208.
- The 18 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 40 mm inner ring.
- Wide (22/23) and light (10/49) executions at 40 mm bore share bore but not OD/width; check the full NJ200 series code before substituting, because housing and shoulder geometry will not interchange.
- The NJ rib arrangement is not interchangeable with another prefix on the same 40 mm seat: inner ring two ribs + one outer rib. Swapping NU for NJ changes axial location behaviour even though the 80×18 mm envelope matches.
- 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 NJ208 (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 NJ208?
NJ208 is an NTN NJ 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. NJ208 is two integral ribs on the inner ring and one rib on the outer ring — it locates the shaft in one axial direction.
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. NJ208 is listed among the ＊ ULTAGE-marked executions in 2203E.
Can NJ208 take axial load and locate a shaft?
the NJ design accepts axial load in one direction and provides one-way shaft location. For two-direction location use an NUP execution or an NJ pair with loose rib rings.
What do Fw and Ew mean for NJ208?
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.