MPNbase

45×68×12 mm bearings

14 models from 4 brands across 2 types share this ISO 15 envelope: 45 mm bore, 68 mm outside diameter, 12 mm width (1.772×2.677×0.472 in), 11.5 mm radial section.

14 models fit this space 4 brands 13 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)
61909 Deep Groove Ball SKF open CN 14 10.8 140
61909-2RS Deep Groove Ball SKF 2RS CN 14 10.8 140
61909-2RS-NSK Deep Groove Ball NSK 2RS CN 15.5 10.9 126
61909-2RS-NTN Deep Groove Ball NTN 2RS CN 14.5 10.4 128
61909-NSK Deep Groove Ball NSK open CN 15.5 10.9 126
61909-NTN Deep Groove Ball NTN open CN 14.5 10.4 128
61909-RSR Deep Groove Ball SKF RSR CN 14 10.8 140
61909-RSR-NSK Deep Groove Ball NSK RSR CN 15.5 10.9 126
61909-RSR-NTN Deep Groove Ball NTN RSR CN 14.5 10.4 128
61909-ZZ Deep Groove Ball NSK ZZ CN 15.5 10.9 126
61909-ZZ-NTN Deep Groove Ball NTN ZZ CN 14.5 10.4 128
71909 Angular Contact Ball GENERIC-ISO open CN — — 125
7909 Angular Contact Ball NTN open CN 17.4 12.9 150
W61909-2RS Deep Groove Ball SKF 2RS CN 12.1 10.8 125

Note: catalogue dynamic load ratings for this envelope span 12.1– 17.4 kN — a 44% spread between designs in the very same 45×68×12 mm space. The higher-rated unit is not an upgrade for every duty (it may run at lower limiting speed), but ignoring the gap will over- or under-life the replacement.

Substitution verification checklist

  1. Load rating. Check C (dynamic) and C0 (static) against the original life calculation — the table above shows which models carry verified catalogue values.
  2. 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.
  3. 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.
  4. Cage and precision. Stamped steel, machined brass and polymer cages, and P0/P6/P5 tolerance classes, carry different speed and shock limits.
  5. 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 45 mm bore bearings for wider or narrower sections, or open a model page for naming-rule decode, applications and graded cross references: 61909, 61909-2RS, 61909-2RS-NSK, 61909-2RS-NTN, 61909-NSK, 61909-NTN, 61909-RSR, 61909-RSR-NSK, 61909-RSR-NTN, 61909-ZZ, 61909-ZZ-NTN, 71909, 7909, W61909-2RS.

Frequently asked questions

Are all 45×68×12 mm bearings interchangeable?

They share the same ISO 15 boundary dimensions — 45 mm bore, 68 mm OD, 12 mm width (1.772×2.677×0.472 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 14 models listed here and must be checked against the duty before substitution.

Is it a drop-in replacement if two bearings both measure 45×68×12?

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 45×68×12 mm in inches?

45×68×12 mm converts to 1.772×2.677×0.472 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 61909, 61909-2RS, 61909-2RS-NSK mount in the same space despite different internal designs.