7218-NTN bearing: complete specifications & equivalents
The 7218-NTN 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 | 130 kN |
| Basic static load rating C0 | 103 kN |
| Fatigue load limit Pu | 7.2 kN |
| Limiting speed (mechanical) | 4400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2180 g |
| Manufacturer designation | NTN 7218 |
| 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 | 18 |
| 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 7218-NTN model number is decoded
7218 is the 90 mm bore member of NTN's medium-duty 7200 single-row family, with a 160 mm outside diameter and 30 mm section width. Decoding 7218: 72 is the single-row dimension series (medium-duty 7200 single-row family), with 18 encodes the 90 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. At roughly 35.0 mm of radial section, the catalogue still quotes 130 kN dynamic capacity for the 90 mm bore. 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. Mount with the thrust against the marked face: the contact angle runs from the low shoulder of the inner ring to the high shoulder of the outer ring, and reversing it throws the capacity away.
Typical equipment & failure modes
Common applications
- marine auxiliary and winch gearbox shafts
- rolling-mill and metalworking drive shafts
- large pump, fan and compressor rotor shafts
- crane and hoist gearbox 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
- thermal runaway from excessive preload: the pair runs hot, grease darkens and the contact ellipse spreads until the raceways smear
- pressed-steel cage pocket wear and rivet loosening after repeated ball skid at light load and high speed
- lubricant starvation scoring at the ball/raceway contact when grease volume or relubrication interval is guessed instead of calculated
- current-erosion pitting on VFD-driven motor shafts, first visible as a grey frosted band across both raceways
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 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.
- The C0 of 103 kN is a static rating, not a permissible running thrust — sizing continuous axial load from C0 alone is a recurring drawing-office error.
- If the application vibrates at standstill (transport, idle machine next to a running line), specify protection: the contact ellipse of a preloaded bearing false-brinells faster than a loose one.
- Catalogue mass and ratings belong to the open execution; shields, seals and resin cages change both the speed ceiling and the thermal behaviour of the same basic size.
- The 130/103 kN ratings and 7.2 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7218; 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 7218?
7218 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 130 kN, C0 103 kN and a 7.2 kN fatigue load limit Pu; the grease limiting speed is 4,400 r/min and the oil rating 5,900 r/min; mass about 2180 g.
How is the 7218 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); with no letter after the digits it is the standard 30 deg contact-angle execution — the 40 deg version carries a B. The 160 mm OD and 30 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7218 support?
One 7218 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 7218?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 4,400 r/min and the oil rating 5,900 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 7218?
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 130 kN / C0 103 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.