NU318 Bearing — Cross-Reference & Equivalents
The NU318 is a cylindrical roller bearing with ISO 15 boundary dimensions 90×190×43 mm. The table below lists how 8 major brands designate it, with catalog links and interchange notes.
Replacing a NU318? The cross-reference table below gives the equivalent part number for every major brand — but read the interchange rules first: an identical size is not always a safe swap.
Specifications
| Bore (d) | 90 mm |
|---|---|
| Outer Diameter (D) | 190 mm |
| Width (B) | 43 mm |
| Type | Cylindrical Roller Bearing |
| Standard | ISO 15 |
Cross-Reference by Brand
| Brand | Part No. | Boundary dims | Catalog |
|---|---|---|---|
| SKF | NU318 | match | SKF catalog ↗ |
| NSK | NU318 | match | NSK catalog ↗ |
| FAG | NU318 | match | FAG catalog ↗ |
| NTN | NU318 | match | NTN catalog ↗ |
| KOYO | NU318 | match | KOYO catalog ↗ |
| NACHI | NU318 | match | NACHI catalog ↗ |
| Timken | NU318 | match | Timken catalog ↗ |
| INA | NU318 | match | INA catalog ↗ |
Interchange notes
All brands build this designation to the same ISO 15 boundary dimensions (d, D, B), so the mounting envelope is interchangeable. For cylindrical roller bearings, matching dimensions is necessary but NOT sufficient — the rib/flange layout is part of the type code and controls axial function: (1) NU has no inner-ring ribs (floats axially, non-locating); N has no outer-ring ribs; NJ locates the shaft in one axial direction; NUP and NF locate in both. An NU205 and N205 share the same size but are NOT interchangeable — they constrain different rings and carry different axial loads, so never substitute across rib types. (2) Inner ring, outer ring and roller-and-cage assembly are separable; do not mix rings across brands or part numbers. (3) The 'E' suffix (e.g. NU205E) is a reinforced internal design with larger rollers — it is not interchangeable with a non-E ring set, so keep both rings the same design. (4) Match internal radial clearance (CN/C3/C4), precision class (P0/P6/P5) and cage type. Load ratings (dynamic Cr, static C0r) are intentionally NOT listed here: they vary by brand and internal design and are a safety-critical selection parameter — read them directly from the manufacturer catalog linked in the table above.
Where to buy a NU318
Compare current listings and prices for the NU318 across brands and sellers:
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FAQ
What bearings are equivalent to a NU318?
The NU318 is built to ISO 15 boundary dimensions 90×190×43 mm by SKF, NSK, FAG, NTN, KOYO, NACHI, Timken, INA. All share the same mounting envelope; match clearance, precision class and (where applicable) seal suffix before substituting.
What are the dimensions of a NU318 bearing?
Bore 90 mm, outer diameter 190 mm, B 43 mm (ISO 15).
Can I replace a NU318 with a different rib type (NU/NJ/N)?
No. The NU318 shares its 90×190×43 mm envelope across brands, but the type letter (NU/N/NJ/NUP/NF) sets which ring carries the guide ribs and therefore the axial function — an NU (non-locating) and an NJ (locates one direction) are not interchangeable even at the same size. Match the full type code, the 'E' design suffix, clearance and precision.
Related sizes
Boundary-dimension cross-reference only. Per the applicable ISO standard (ISO 15 for ball, ISO 355 for tapered), the boundary dimensions are common across brands, so the mounting envelope is interchangeable. This is NOT a drop-in part equivalence. Internal clearance, precision class, seal/shield type (where applicable), cage material and factory lubrication are encoded in brand-specific suffixes and must be matched separately. Always verify against the manufacturer's catalog before substituting.