35×80×21 mm bearings
6 models from 3 brands across 3 types share this ISO 15 envelope: 35 mm bore, 80 mm outside diameter, 21 mm width (1.378×3.150×0.827 in), 22.5 mm radial section.
6 models fit this space 3 brands 4 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) |
|---|---|---|---|---|---|---|---|
| 6307 | Deep Groove Ball | SKF | open | CN | 35.1 | 19 | 460 |
| 6307-2RS | Deep Groove Ball | SKF | 2RS | CN | 35.1 | 19 | 460 |
| 6307-RSR | Deep Groove Ball | NSK | RSR | CN | 36.5 | 19.2 | 464 |
| 6307-ZZ | Deep Groove Ball | SKF | ZZ | CN | 35.1 | 19 | 480 |
| 7307 | Angular Contact Ball | GENERIC-ISO | open | CN | — | — | 436 |
| NU307 | Cylindrical Roller | GENERIC-ISO | open | CN | — | — | 436 |
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 35 mm bore bearings for wider or narrower sections, or open a model page for naming-rule decode, applications and graded cross references: 6307, 6307-2RS, 6307-RSR, 6307-ZZ, 7307, NU307.
Frequently asked questions
Are all 35×80×21 mm bearings interchangeable?
They share the same ISO 15 boundary dimensions — 35 mm bore, 80 mm OD, 21 mm width (1.378×3.150×0.827 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 6 models listed here and must be checked against the duty before substitution.
Is it a drop-in replacement if two bearings both measure 35×80×21?
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 35×80×21 mm in inches?
35×80×21 mm converts to 1.378×3.150×0.827 in, with a 22.5 mm (0.886 in) radial section height. These are the ISO 15 general-plan envelope dimensions shared across manufacturers, which is why models such as 6307, 6307-2RS, 6307-RSR mount in the same space despite different internal designs.