7228B bearing: complete specifications & equivalents
The 7228B 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 | 203 kN |
| Basic static load rating C0 | 195 kN |
| Fatigue load limit Pu | 10.1 kN |
| Limiting speed (mechanical) | 2300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 8780 g |
| Manufacturer designation | NTN 7228B |
| 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 | — |
| 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 7228B model number is decoded
The medium-duty 7200 single-row family entry 7228B carries a 140 mm bore in a 250 mm outside diameter, 42 mm wide envelope. The designation breaks down as 72 is the single-row dimension series (medium-duty 7200 single-row family); 28 encodes the 140 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 static margin, C0 195 kN versus C 203 kN, is what supports slow oscillating duty and shock without immediate brinelling. Choose the medium-duty 7200 single-row family when the shaft needs a stiff locating support and the axial component is known to act mostly one way. Set preload or end-play with the pair as a unit and lock the adjustment; a single angular-contact bearing cannot run free like a deep-groove one.
Typical equipment & failure modes
Common applications
- heavy industrial gearbox main shafts
- large fan, blower and turbo-compressor rotors
- rolling-mill backup and drive spindles
- crusher and mill pinion 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
- thermal runaway from excessive preload: the pair runs hot, grease darkens and the contact ellipse spreads until the raceways smear
- machined-cage land scoring when a high-speed spindle runs past its grease rating and the cage runs dry on its guidance surface
- edge loading and early spalling from housing bores that are out of round or shoulders that are too small for the ring face
- lubricant starvation scoring at the ball/raceway contact when grease volume or relubrication interval is guessed instead of calculated
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 40 deg B-execution raises axial capacity but lowers the speed ceiling — do not copy the standard-bearing speed and preload settings onto it.
- Grease rated for deep-groove motor duty is not automatically right at 2,300 r/min with preload; check the grease speed factor against the catalogue figure.
- Never use a four-point or double-row bearing as a like-for-like swap for a single 7228B without re-checking axial float, heat and housing width — the kinematics differ.
- Do not pair two random 7228B bearings from stock and expect catalogue paired ratings — matched-set grinding is what makes DB/DF/DT preload behave, and NTN sells those as separate order numbers.
- The 203/195 kN ratings and 10.1 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7228B; 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 7228B?
7228B 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 203 kN, C0 195 kN and a 10.1 kN fatigue load limit Pu; the grease limiting speed is 2,300 r/min and the oil rating 3,100 r/min; mass about 8780 g.
How is the 7228B 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), and the trailing B marks the 40 deg contact-angle execution (the no-letter standard bearing works at 30 deg). The 250 mm OD and 42 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7228B support?
One 7228B 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 7228B?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 2,300 r/min and the oil rating 3,100 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 7228B?
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 203 kN / C0 195 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.