7234B bearing: complete specifications & equivalents
The 7234B is a ISO 15 radial bearing sized 170 x 310 x 52 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 170 mm |
| Outer diameter D | 310 mm |
| Width B | 52 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 295 kN |
| Basic static load rating C0 | 325 kN |
| Fatigue load limit Pu | 15.6 kN |
| Limiting speed (mechanical) | 1900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 17000 g |
| Manufacturer designation | NTN 7234B |
| 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 | 6.693 in |
|---|---|
| Outer diameter D | 12.205 in |
| Width B | 2.047 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 70 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) | 29 of 36 |
| Bore above smallest 7200-series size | 160 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 7234B model number is decoded
7234B is an NTN single-row angular contact ball bearing: medium-duty 7200 single-row family, listed in NTN Ball and Roller Bearings CAT.No.2203E at 170 x 310 x 52 mm. Reading the code: 72 is the single-row dimension series (medium-duty 7200 single-row family), 34 encodes the 170 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). Catalogue mass is about 17000 g, which at this 70.0 mm radial section keeps the bearing comfortably inside high-speed spindle weight budgets. 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. Heat-mounting to 80-90 deg C is the clean route onto a 170 mm shaft; drive-fits through the balls transmit force through the contact ellipse and can brinell it.
Typical equipment & failure modes
Common applications
- rolling-mill backup and drive spindles
- crusher and mill pinion shafts
- large pump and turbine auxiliary shafts
- steel-plant conveyor and table roll drives
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
- machined-cage land scoring when a high-speed spindle runs past its grease rating and the cage runs dry on its guidance surface
- contamination-induced denting — hard particles rolled into the contact ellipse become the initiation points for surface fatigue
- 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
- At this size the shaft fit, shoulder geometry and preload procedure dominate the outcome; a 170 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 1,900 r/min with preload; check the grease speed factor against the catalogue figure.
- Do not pair two random 7234B 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.
- 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.
- The 295/325 kN ratings and 15.6 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7234B; 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 7234B?
7234B is a single-row angular contact ball bearing to ISO 15: 170 mm bore, 310 mm outside diameter, 52 mm width (6.693 x 12.205 x 2.047 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 295 kN, C0 325 kN and a 15.6 kN fatigue load limit Pu; the grease limiting speed is 1,900 r/min and the oil rating 2,500 r/min; mass about 17000 g.
How is the 7234B designation structured?
72 is the single-row dimension series (medium-duty 7200 single-row family); 34 encodes the 170 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 310 mm OD and 52 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7234B support?
One 7234B 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 7234B?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 1,900 r/min and the oil rating 2,500 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 7234B?
The 170/310/52 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 295 kN / C0 325 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.