MPNbase

55×100×21 mm bearings

49 models from 4 brands across 5 types share this ISO 15 envelope: 55 mm bore, 100 mm outside diameter, 21 mm width (2.165×3.937×0.827 in), 22.5 mm radial section.

49 models fit this space 4 brands 49 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)
1211 Self-Aligning Ball NTN open — 26.9 10 708
1211-EKTN9 Self-Aligning Ball SKF open CN 27.6 10.6 710
1211-ETN9 Self-Aligning Ball SKF open CN 27.6 10.6 710
1211K Self-Aligning Ball NTN open — 26.9 10 708
1726211-2RS1 Insert (Y-bearings) SKF 2RS CN 43.6 29 600
211 Deep Groove Ball SKF open CN 48.4 44 660
211-ZZ Deep Groove Ball SKF ZZ CN 48.4 44 660
6211 Deep Groove Ball SKF open CN 46.2 29 610
6211-2RS Deep Groove Ball SKF 2RS CN 46.2 29 620
6211-2RS-FAG Deep Groove Ball FAG 2RS CN 46.5 29 600
6211-2RS-NSK Deep Groove Ball NSK 2RS CN 47.5 29.3 619
6211-2RS-NTN Deep Groove Ball NTN 2RS CN 48 29.2 601
6211-FAG Deep Groove Ball FAG open CN 46.5 29 580
6211-M Deep Groove Ball SKF open CN 46.2 29 720
6211-NSK Deep Groove Ball NSK open CN 47.5 29.3 619
6211-NTN Deep Groove Ball NTN open CN 48 29.2 601
6211-RSR Deep Groove Ball NSK RSR CN 47.5 29.3 619
6211-RSR-NTN Deep Groove Ball NTN RSR CN 48 29.2 601
6211-ZZ Deep Groove Ball SKF ZZ CN 46.2 29 640
6211-ZZ-FAG Deep Groove Ball FAG ZZ CN 46.5 29 580
6211-ZZ-NSK Deep Groove Ball NSK ZZ CN 47.5 29.3 619
6211-ZZ-NTN Deep Groove Ball NTN ZZ CN 48 29.2 601
7211 Angular Contact Ball SKF open CN 46.2 36 620
7211-ACCBM Angular Contact Ball SKF open CN 57 45 620
7211-BE-2RZP Angular Contact Ball SKF RSR CN 46.2 36 620
7211-BECBM Angular Contact Ball SKF open CN 49 40 620
7211-BECBP Angular Contact Ball SKF open CN 49 40 620
7211-BECBPH Angular Contact Ball SKF open CN 49 40 620
7211-BECBY Angular Contact Ball SKF open CN 51 42.5 620
7211-BEP Angular Contact Ball SKF open CN 46.2 36 620
7211-NTN Angular Contact Ball NTN open CN 56.5 39.5 600
7211B Angular Contact Ball NTN open CN 51.5 36 612
N211 Cylindrical Roller NTN open CN 64.5 62.5 626
N211-ECP Cylindrical Roller SKF open CN 96.5 95 650
N211EA Cylindrical Roller NTN open CN 102 98.5 635
NF211 Cylindrical Roller NTN open CN 64.5 62.5 626
NF211EA Cylindrical Roller NTN open CN 102 98.5 635
NJ211 Cylindrical Roller NTN open CN 64.5 62.5 626
NJ211-ECP Cylindrical Roller SKF open CN 96.5 95 670
NJ211EA Cylindrical Roller NTN open CN 102 98.5 635
NU211 Cylindrical Roller SKF open CN 96.5 95 660
NU211-NTN Cylindrical Roller NTN open CN 64.5 62.5 626
NU211EA Cylindrical Roller NTN open CN 102 98.5 635
NUP211 Cylindrical Roller NTN open CN 64.5 62.5 626
NUP211-ECP Cylindrical Roller SKF open CN 96.5 95 680
NUP211EA Cylindrical Roller NTN open CN 102 98.5 635
QJ-211-MA Angular Contact Ball SKF open CN 85 83 770
QJ-211-N2MA Angular Contact Ball SKF open CN 85 83 770
QJ211 Angular Contact Ball NTN open CN 71 112 780

Note: catalogue dynamic load ratings for this envelope span 26.9– 102.0 kN — a 279% spread between designs in the very same 55×100×21 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 55 mm bore bearings for wider or narrower sections, or open a model page for naming-rule decode, applications and graded cross references: 1211, 1211-EKTN9, 1211-ETN9, 1211K, 1726211-2RS1, 211, 211-ZZ, 6211, 6211-2RS, 6211-2RS-FAG, 6211-2RS-NSK, 6211-2RS-NTN, 6211-FAG, 6211-M, 6211-NSK, 6211-NTN, 6211-RSR, 6211-RSR-NTN, 6211-ZZ, 6211-ZZ-FAG, 6211-ZZ-NSK, 6211-ZZ-NTN, 7211, 7211-ACCBM, 7211-BE-2RZP, 7211-BECBM, 7211-BECBP, 7211-BECBPH, 7211-BECBY, 7211-BEP, 7211-NTN, 7211B, N211, N211-ECP, N211EA, NF211, NF211EA, NJ211, NJ211-ECP, NJ211EA, NU211, NU211-NTN, NU211EA, NUP211, NUP211-ECP, NUP211EA, QJ-211-MA, QJ-211-N2MA, QJ211.

Frequently asked questions

Are all 55×100×21 mm bearings interchangeable?

They share the same ISO 15 boundary dimensions — 55 mm bore, 100 mm OD, 21 mm width (2.165×3.937×0.827 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 49 models listed here and must be checked against the duty before substitution.

Is it a drop-in replacement if two bearings both measure 55×100×21?

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 55×100×21 mm in inches?

55×100×21 mm converts to 2.165×3.937×0.827 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 1211, 1211-EKTN9, 1211-ETN9 mount in the same space despite different internal designs.