17×40×12 mm bearings
35 models from 4 brands across 5 types share this ISO 15 envelope: 17 mm bore, 40 mm outside diameter, 12 mm width (0.669×1.575×0.472 in), 11.5 mm radial section.
35 models fit this space 4 brands 35 with catalogue C rating
Dimensional interchange — verify before substituting
These bearings are interchangeable on boundary dimensions per ISO 15 — same bore, OD and width. They are not guaranteed drop-in equivalents: compare load ratings, seals, clearance, cage, precision and axial-locating design for the specific duty. Models without a catalogue C rating on this site carry ISO 15 geometry only; request the manufacturer table before a load-critical replacement.
| Model | Type | Brand | Seal | Clearance | C (kN) | C0 (kN) | Mass (g) |
|---|---|---|---|---|---|---|---|
| 1203 | Self-Aligning Ball | NTN | open | — | 8 | 2.01 | 74 |
| 1203-ETN9 | Self-Aligning Ball | SKF | open | CN | 8.84 | 2.2 | 73 |
| 1726203-2RS1 | Insert (Y-bearings) | SKF | 2RS | CN | 9.56 | 4.75 | 60 |
| 6203 | Deep Groove Ball | SKF | open | CN | 9.95 | 4.75 | 65 |
| 6203-2RS | Deep Groove Ball | SKF | 2RS | CN | 9.95 | 4.75 | 67 |
| 6203-2RS-FAG | Deep Groove Ball | FAG | 2RS | CN | 11 | 4.75 | 66 |
| 6203-2RS-NSK | Deep Groove Ball | NSK | 2RS | CN | 10.5 | 4.8 | 67 |
| 6203-2RS-NTN | Deep Groove Ball | NTN | 2RS | CN | 10.6 | 4.6 | 66 |
| 6203-FAG | Deep Groove Ball | FAG | open | CN | 11 | 4.75 | 61 |
| 6203-NSK | Deep Groove Ball | NSK | open | CN | 10.5 | 4.8 | 67 |
| 6203-NTN | Deep Groove Ball | NTN | open | CN | 10.6 | 4.6 | 66 |
| 6203-RSR | Deep Groove Ball | SKF | RSR | CN | 9.95 | 4.75 | 67 |
| 6203-RSR-NSK | Deep Groove Ball | NSK | RSR | CN | 10.5 | 4.8 | 67 |
| 6203-RSR-NTN | Deep Groove Ball | NTN | RSR | CN | 10.6 | 4.6 | 66 |
| 6203-ZZ | Deep Groove Ball | SKF | ZZ | CN | 9.95 | 4.75 | 68 |
| 6203-ZZ-FAG | Deep Groove Ball | FAG | ZZ | CN | 11 | 4.75 | 67 |
| 6203-ZZ-NSK | Deep Groove Ball | NSK | ZZ | CN | 10.5 | 4.8 | 67 |
| 6203-ZZ-NTN | Deep Groove Ball | NTN | ZZ | CN | 10.6 | 4.6 | 66 |
| 7203 | Angular Contact Ball | SKF | open | CN | 10.4 | 5.5 | 65 |
| 7203-ACCBM | Angular Contact Ball | SKF | open | CN | 12.5 | 6.7 | 65 |
| 7203-BE-2RZP | Angular Contact Ball | SKF | RSR | CN | 10.4 | 5.5 | 63 |
| 7203-BECBM | Angular Contact Ball | SKF | open | CN | 11 | 5.85 | 65 |
| 7203-BECBP | Angular Contact Ball | SKF | open | CN | 11 | 5.85 | 65 |
| 7203-BEP | Angular Contact Ball | SKF | open | CN | 10.4 | 5.5 | 65 |
| 7203-BEY | Angular Contact Ball | SKF | open | CN | 11.1 | 6.1 | 65 |
| 7203-NTN | Angular Contact Ball | NTN | open | CN | 13.2 | 6.6 | 64 |
| 7203B | Angular Contact Ball | NTN | open | CN | 12.2 | 6.1 | 66 |
| N203-ECP | Cylindrical Roller | SKF | open | CN | 20 | 14.3 | 66 |
| NJ203-ECP | Cylindrical Roller | SKF | open | CN | 20 | 14.3 | 69 |
| NU203-ECP | Cylindrical Roller | SKF | open | CN | 20 | 14.3 | 68 |
| NUP203-ECP | Cylindrical Roller | SKF | open | CN | 20 | 14.3 | 72 |
| QJ-203-N2MA | Angular Contact Ball | SKF | open | CN | 17 | 11.4 | 82 |
| W6203 | Deep Groove Ball | SKF | open | CN | 8.06 | 4.75 | 62 |
| W6203-2RS | Deep Groove Ball | SKF | 2RS | CN | 8.06 | 4.75 | 64 |
| W6203-ZZ | Deep Groove Ball | SKF | ZZ | CN | 8.06 | 4.75 | 66 |
Substitution verification checklist
- Load rating. Check C (dynamic) and C0 (static) against the original life calculation — the table above shows which models carry verified catalogue values.
- Sealing. Open, -ZZ shields and -2RS contact seals are not equivalent in friction, speed or contamination protection; match the housing environment, not just the suffix on the old box.
- Internal clearance. CN/C3/C4 changes with fit and operating temperature; an interference inner-ring mount commonly needs C3 where the bench bearing ran CN.
- Cage and precision. Stamped steel, machined brass and polymer cages, and P0/P6/P5 tolerance classes, carry different speed and shock limits.
- Locating behaviour. Within one envelope an NU cylindrical roller floats axially while an NJ/NUP locates; ball designs take thrust that roller locating schemes do not. Preserve the shaft's locating arrangement.
Browse all 17 mm bore bearings for wider or narrower sections, or open a model page for naming-rule decode, applications and graded cross references: 1203, 1203-ETN9, 1726203-2RS1, 6203, 6203-2RS, 6203-2RS-FAG, 6203-2RS-NSK, 6203-2RS-NTN, 6203-FAG, 6203-NSK, 6203-NTN, 6203-RSR, 6203-RSR-NSK, 6203-RSR-NTN, 6203-ZZ, 6203-ZZ-FAG, 6203-ZZ-NSK, 6203-ZZ-NTN, 7203, 7203-ACCBM, 7203-BE-2RZP, 7203-BECBM, 7203-BECBP, 7203-BEP, 7203-BEY, 7203-NTN, 7203B, N203-ECP, NJ203-ECP, NU203-ECP, NUP203-ECP, QJ-203-N2MA, W6203, W6203-2RS, W6203-ZZ.
Frequently asked questions
Are all 17×40×12 mm bearings interchangeable?
They share the same ISO 15 boundary dimensions — 17 mm bore, 40 mm OD, 12 mm width (0.669×1.575×0.472 in) — so they fit the same shaft, housing bore and axial space. Interchangeability ends at the envelope: dynamic load rating, seal arrangement, internal clearance, cage and precision class differ between the 35 models listed here and must be checked against the duty before substitution.
Is it a drop-in replacement if two bearings both measure 17×40×12?
Only after verification. Confirm five things in order: (1) the C/C0 load ratings meet the original life calculation, (2) the seal type is equivalent or acceptable for the contamination level (open vs -ZZ vs -2RS), (3) internal clearance matches (CN/C3/C4 — an interference fit changes residual play), (4) cage material and precision class suit the speed, and (5) the axial-locating behaviour is the same (for example an NU cylindrical roller floats while an NJ locates one way). Same dimensions alone never guarantee equal performance.
What is 17×40×12 mm in inches?
17×40×12 mm converts to 0.669×1.575×0.472 in, with a 11.5 mm (0.453 in) radial section height. These are the ISO 15 general-plan envelope dimensions shared across manufacturers, which is why models such as 1203, 1203-ETN9, 1726203-2RS1 mount in the same space despite different internal designs.