7228 bearing: complete specifications & equivalents
The 7228 is a ISO 15 radial bearing sized 140 x 250 x 42 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 140 mm |
| Outer diameter D | 250 mm |
| Width B | 42 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 225 kN |
| Basic static load rating C0 | 215 kN |
| Fatigue load limit Pu | 11.7 kN |
| Limiting speed (mechanical) | 2700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 8780 g |
| Manufacturer designation | NTN 7228 |
| 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 | 5.512 in |
|---|---|
| Outer diameter D | 9.843 in |
| Width B | 1.654 in |
| ISO bore code | 28 |
| Radial section height (D−d)/2 | 55 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) | 26 of 36 |
| Bore above smallest 7200-series size | 130 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 7228 model number is decoded
At 140 x 250 x 42 mm, NTN 7228 sits in the medium-duty 7200 single-row family of the angular-contact programme. NTN builds the number from 72 is the single-row dimension series (medium-duty 7200 single-row family), then 28 encodes the 140 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. Because the contact line is angled, one bearing of this type takes radial load plus thrust from one direction only — the opposite direction needs a second bearing or a matched set. Size selection is usually finished by checking that the C0 of 215 kN covers the maximum static or shock condition with the catalogue safety factor, not only the running load. Heat-mounting to 80-90 deg C is the clean route onto a 140 mm shaft; drive-fits through the balls transmit force through the contact ellipse and can brinell it.
Typical equipment & failure modes
Common applications
- large fan, blower and turbo-compressor rotors
- rolling-mill backup and drive spindles
- crusher and mill pinion shafts
- large pump and turbine auxiliary shafts
Known failure patterns
- false brinelling on the raceway contact ellipses when a preloaded spindle sits vibrating at standstill — visible as evenly spaced flute-like wear at ball pitch
- 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
- flaking that starts at the raceway shoulder on the thrust-loaded side when axial load repeatedly exceeds the design share
Selection pitfalls — read before you substitute
- At this size the shaft fit, shoulder geometry and preload procedure dominate the outcome; a 140 mm bore bearing forgives nothing in a poorly machined housing.
- 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.
- 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.
- A single-row angular contact left loose on the shaft to "help assembly" will fret the seat: the contact angle keeps driving the ring axially under load.
- The 2,700 r/min speed figure assumes the catalogue lubrication state and a correctly set pair; real limits drop fast with excess grease fill or heavy preload.
- The 225/215 kN ratings and 11.7 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7228; 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 7228?
7228 is a single-row angular contact ball bearing to ISO 15: 140 mm bore, 250 mm outside diameter, 42 mm width (5.512 x 9.843 x 1.654 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 225 kN, C0 215 kN and a 11.7 kN fatigue load limit Pu; the grease limiting speed is 2,700 r/min and the oil rating 3,600 r/min; mass about 8780 g.
How is the 7228 designation structured?
72 is the single-row dimension series (medium-duty 7200 single-row family); 28 encodes the 140 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 250 mm OD and 42 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7228 support?
One 7228 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 7228?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 2,700 r/min and the oil rating 3,600 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 7228?
The 140/250/42 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 225 kN / C0 215 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.