NU1008 bearing: complete specifications & equivalents
The NU1008 is a ISO 15 radial bearing sized 40 x 68 x 15 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 | 68 mm |
| Width B | 15 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 30.5 kN |
| Basic static load rating C0 | 29 kN |
| Fatigue load limit Pu | 3.55 kN |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 217 g |
| Manufacturer designation | NTN NU1008 |
| 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 & NU1000-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.677 in |
| Width B | 0.591 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 14 mm |
| Smallest bore in NU1000-series | 25 mm |
| Largest outer diameter in NU1000-series | 1090 mm |
| Width range across NU1000-series | 12–150 mm |
| Bore position in NU1000-series (smallest first) | 4 of 47 |
| Bore above smallest NU1000-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU1008-ML | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×68×15 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 NU1008 model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, NU1008 appears as a 40 mm bore single-row cylindrical roller bearing (30.5 kN C / 29 kN C0) with a pressed sheet-steel cage, listed to the ISO 15 boundary plan. The leading NU defines the rib arrangement (outer ring ribbed, inner ring ribless); the dimension-series digits and the two-digit bore code resolve to 40 mm, with 68 mm OD and 15 mm width from the ISO 15 general plan. With C 30.5 kN and C0 29 kN (C0/C ≈ 0.95) the bearing is proportioned for heavy radial load; the NU design carries no axial load and floats axially on both sides. The 0.8 kN-per-mm-bore figure (30.5 kN over 40 mm) lets a NU1008 interchange candidate be screened quickly against the same-envelope ball or roller alternatives. Housing and shaft fillets must clear the ring chamfers of NU1008; an oversized radius locks the ring on its face and tilts the 15 mm-wide seat.
Typical equipment & failure modes
Common applications
- industrial gearbox input and output shafts
- medium electric-motor and generator shafts
- pump and compressor crankshafts and rotors
- machine-tool gearbox and spindle radial sets
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
- micro-pitting when the EHL film falls below the composite roughness at high specific load
- fretting corrosion on a loose rotating shaft seat
- hard-particle indentation of raceways in unfiltered oil or open arrangements
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 NU1008.
- Grease limiting speed 11,000 r/min and oil 13,000 r/min are different limits for NU1008: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- If the shaft must be located both ways, do not use NU1008 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
- The 15 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.
- Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU1008 skids at 11,000 r/min and fails by smearing long before L10 fatigue.
- The 30.5/29 kN ratings, 3.55 kN Pu and 217 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU1008 (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 NU1008?
NU1008 is an NTN NU single-row cylindrical roller bearing to ISO 15: 40 mm bore, 68 mm OD and 15 mm width (1.575 × 2.677 × 0.591 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 30.5 kN, C0 29 kN, Pu 3.55 kN, grease limiting speed 11,000 r/min, oil 13,000 r/min, mass about 217 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. NU1008 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. NU1008 is supplied in the standard open execution shown in the table.
Can NU1008 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 NU1008?
Fw is the inner sub-assembly raceway/roller-set envelope diameter and Ew the outer-ring raceway diameter printed for geometric checks: Fw 47 mm, Ew 61 mm. The nominal bore/OD remain 40/68 mm; Fw/Ew describe the rolling-contact path, and speeds still run to 11,000 r/min grease / 13,000 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.