7211-NTN bearing: complete specifications & equivalents
The 7211-NTN is a ISO 15 radial bearing sized 55 x 100 x 21 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 55 mm |
| Outer diameter D | 100 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 56.5 kN |
| Basic static load rating C0 | 39.5 kN |
| Fatigue load limit Pu | 3.1 kN |
| Limiting speed (mechanical) | 7100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 600 g |
| Manufacturer designation | NTN 7211 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & 7200-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 0.827 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 22.5 mm |
| Smallest bore in 7200-series | 10 mm |
| Largest outer diameter in 7200-series | 540 mm |
| Width range across 7200-series | 9–85 mm |
| Bore position in 7200-series (smallest first) | 12 of 36 |
| Bore above smallest 7200-series size | 45 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 7211-NTN model number is decoded
At 55 x 100 x 21 mm, NTN 7211 sits in the medium-duty 7200 single-row family of the angular-contact programme. Two fields make up the code — 72 is the single-row dimension series (medium-duty 7200 single-row family) and 11 encodes the 55 mm bore (bore code x 5); with no letter after the digits it is the standard 30 deg contact-angle execution — the 40 deg version carries a B. NTN prints 56.5 kN dynamic and 39.5 kN static for this size and a 3.1 kN fatigue load limit Pu. Selection starts from the thrust share: as axial load grows past roughly half the radial load, an angular-contact position of this section usually outlives a deep-groove one. Grease quantity matters as much as grade at 7,100 r/min: fill about a third of the free space and let the bearing purge on first run.
Typical equipment & failure modes
Common applications
- agricultural gearbox and PTO shaft supports
- printing-press cylinder and folder shafts
- machine-tool spindle cartridges and driven tooling
- industrial pump and blower impeller shafts
Known failure patterns
- impact brinelling dents on the 30 deg contact path after a shaft-side hammer blow during mounting, because axial shock travels straight through the contact angle
- loss of preload after housing-fret or shaft creep, leaving the pair loose — ball skidding, cage rattle and a falling natural frequency follow
- pressed-steel cage pocket wear and rivet loosening after repeated ball skid at light load and high speed
- contamination-induced denting — hard particles rolled into the contact ellipse become the initiation points for surface fatigue
- contamination-induced denting — hard particles rolled into the contact ellipse become the initiation points for surface fatigue
Selection pitfalls — read before you substitute
- In this size class the common miss is lubrication interval, not fit — a 55 mm spindle at the catalogue speeds needs a calculated relubrication plan, not a calendar one.
- The standard 30 deg bearing and its B (40 deg) sibling share the envelope; picking between them is a load-direction decision, not a quality upgrade.
- A 7211 mounted the wrong way round still turns smoothly by hand; the failure shows up weeks later as raceway flaking on the unloaded-looking side.
- The C0 of 39.5 kN is a static rating, not a permissible running thrust — sizing continuous axial load from C0 alone is a recurring drawing-office error.
- Never use a four-point or double-row bearing as a like-for-like swap for a single 7211 without re-checking axial float, heat and housing width — the kinematics differ.
- The 56.5/39.5 kN ratings and 3.1 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7211; internal geometry legitimately differs between manufacturers, so re-verify ratings, contact angle and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 7211?
7211 is a single-row angular contact ball bearing to ISO 15: 55 mm bore, 100 mm outside diameter, 21 mm width (2.165 x 3.937 x 0.827 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 56.5 kN, C0 39.5 kN and a 3.1 kN fatigue load limit Pu; the grease limiting speed is 7,100 r/min and the oil rating 9,500 r/min; mass about 600 g.
How is the 7211 designation structured?
72 is the single-row dimension series (medium-duty 7200 single-row family); 11 encodes the 55 mm bore (bore code x 5); with no letter after the digits it is the standard 30 deg contact-angle execution — the 40 deg version carries a B. The 100 mm OD and 21 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7211 support?
One 7211 alone takes thrust in one direction only, along its 30 deg contact angle; reversing thrust calls for a second bearing or a factory-matched DB/DF/DT pair (the catalogue right-hand columns list the paired ratings). Radial load is always carried as a combined load through the angled contact.
What lubrication speeds does NTN print for 7211?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 7,100 r/min and the oil rating 9,500 r/min. These are catalogue ceilings for a correctly mounted bearing with the stated lubricant; preload, fill quantity, ambient heat and paired arrangements all move the real limit.
What should be checked before substituting another make for 7211?
The 55/100/21 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 56.5 kN / C0 39.5 kN, the speed figures, contact angle and suffix meaning against the donor catalogue before swapping on a rated drive.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.