NTN 6311-2Z/C4

Deep groove ball · 2Z shield

The seat — 55 MM × 120 MM × 29 MM

Bore

55 MM

Outside dia

120 MM

Width

29 MM

Type

Deep groove ball

Seal

2Z shield

Clearance

Precision

ABEC-1 (P0)

Dynamic C

74.1 kN

Static C0

45.0 kN

138 other designations in the catalogue share this bore × outside diameter × width. Each was compared on the four fields every bearing row carries — Type, Seal, Clearance, Precision — as recorded, case- and separator-insensitively. All four agreeing puts a designation in the first list; anything else, a difference or a blank, puts it in the second with the fields named.

Candidates at the recorded dimensions above

May substitute — 0 designations

No designation in this seat matches this part on all four compared fields.

Check before substituting — 138 designations · top 12 shown

Part number	Manufacturer	C	Differs from this part
21311 E	NTN	159.0 kN	Type: Spherical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: CN (Normal) — this part: C4
21311 E/C3	NTN	159.0 kN	Type: Spherical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: C3 — this part: C4
21311 EK	NTN	159.0 kN	Type: Spherical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: CN (Normal) — this part: C4
21311 EK/C3	NTN	159.0 kN	Type: Spherical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: C3 — this part: C4
N 311 ECM	NTN	156.0 kN	Type: Cylindrical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: CN (Normal) — this part: C4
N 311 ECP	NTN	156.0 kN	Type: Cylindrical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: CN (Normal) — this part: C4
NJ 311 ECJ	NTN	156.0 kN	Type: Cylindrical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: CN (Normal) — this part: C4
NJ 311 ECJ/C3	NTN	156.0 kN	Type: Cylindrical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: C3 — this part: C4
NJ 311 ECM	NTN	156.0 kN	Type: Cylindrical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: CN (Normal) — this part: C4
NJ 311 ECML	NTN	156.0 kN	Type: Cylindrical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: CN (Normal) — this part: C4
NJ 311 ECP	NTN	156.0 kN	Type: Cylindrical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: CN (Normal) — this part: C4
NJ 311 ECP/C3	NTN	156.0 kN	Type: Cylindrical — this part: Deep groove ball Seal: Open — this part: 2Z shield Clearance: C3 — this part: C4

What this sheet is — and what the catalogue did not say

The envelope is recorded dimensions only: the same bore, outside diameter and width. Every designation above shares all three, or it would not be on this page.
The four compared fields are Type, Seal, Clearance, Precision. Two recorded spellings were counted to mean one value and are read as one: CN/Normal = CN, and ABEC-1/P0 = P0. A third precision spelling, P0/Class4, is deliberately not equated with either — the catalogue's meaning for it has not been sourced, so it lands in the warnings where both spellings are printed for the reader to judge.
A blank is a difference. Missing is the absence of the proof, not the proof.
Cage material and ring material are never compared: the catalogue records neither, on any bearing row.
Suffixes the catalogue does not record separately — a snap ring (NR) and anything else outside those four fields — are not compared, and this sheet does not claim they match.
Ranking is recorded dynamic load, strongest first, with an unrecorded rating ranked last. It orders the lists; it is not a verdict.
Compiled from catalogue records. This is not a manufacturer interchange list, no manufacturer has confirmed any line on it, and it does not know what job the bearing is doing. Verify before fitting.

Anyone with this link can view this part and its recorded candidate comparison.

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