7218B bearing: complete specifications & equivalents
The 7218B is a ISO 15 radial bearing sized 90 x 160 x 30 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 90 mm |
| Outer diameter D | 160 mm |
| Width B | 30 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 118 kN |
| Basic static load rating C0 | 94 kN |
| Fatigue load limit Pu | 6.3 kN |
| Limiting speed (mechanical) | 3800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2220 g |
| Manufacturer designation | NTN 7218B |
| 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 | 3.543 in |
|---|---|
| Outer diameter D | 6.299 in |
| Width B | 1.181 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 35 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) | 19 of 36 |
| Bore above smallest 7200-series size | 80 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 7218B model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 7218B appears as a medium-duty 7200 single-row family bearing of 90 mm bore, 160 mm outside diameter and 30 mm width. Reading the code: 72 is the single-row dimension series (medium-duty 7200 single-row family), 18 encodes the 90 mm bore (bore code x 5), and the trailing B marks the 40 deg contact-angle execution (the no-letter standard bearing works at 30 deg). NTN prints 118 kN dynamic and 94 kN static for this size and a 6.3 kN fatigue load limit Pu. The 90/160/30 envelope is an ISO 15 boundary plan, so dimensional interchange with other makers holds — ratings and internal geometry do not automatically follow. Shaft and housing shoulders must clear the ring corners yet support enough face — the catalogue abutment diameters for the 90 mm bore give the working limits.
Typical equipment & failure modes
Common applications
- crane and hoist gearbox shafts
- paper-machine roll and calendar drives
- extruder and mixer gearbox output shafts
- mining conveyor head-shaft positions
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
- current-erosion pitting on VFD-driven motor shafts, first visible as a grey frosted band across both raceways
- edge loading and early spalling from housing bores that are out of round or shoulders that are too small for the ring face
Selection pitfalls — read before you substitute
- Bearings of 90 mm bore arrive heavy enough that handling damage (dents from slings, tilting on the shaft) is a real failure precursor — use proper lifting and heating kit.
- The 40 deg B-execution raises axial capacity but lowers the speed ceiling — do not copy the standard-bearing speed and preload settings onto it.
- The C0 of 94 kN is a static rating, not a permissible running thrust — sizing continuous axial load from C0 alone is a recurring drawing-office error.
- On a 90 mm shaft, an interference fit eats internal clearance; skipping the clearance/preload recalculation is the classic cause of a new bearing running 20 deg C hotter than the drawing suggests.
- Never use a four-point or double-row bearing as a like-for-like swap for a single 7218B without re-checking axial float, heat and housing width — the kinematics differ.
- The 118/94 kN ratings and 6.3 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7218B; 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 7218B?
7218B is a single-row angular contact ball bearing to ISO 15: 90 mm bore, 160 mm outside diameter, 30 mm width (3.543 x 6.299 x 1.181 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 118 kN, C0 94 kN and a 6.3 kN fatigue load limit Pu; the grease limiting speed is 3,800 r/min and the oil rating 5,000 r/min; mass about 2220 g.
How is the 7218B designation structured?
72 is the single-row dimension series (medium-duty 7200 single-row family); 18 encodes the 90 mm bore (bore code x 5), and the trailing B marks the 40 deg contact-angle execution (the no-letter standard bearing works at 30 deg). The 160 mm OD and 30 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7218B support?
One 7218B alone takes thrust in one direction only, along its 40 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 7218B?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 3,800 r/min and the oil rating 5,000 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 7218B?
The 90/160/30 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 118 kN / C0 94 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.