7238 bearing: complete specifications & equivalents
The 7238 is a ISO 15 radial bearing sized 190 x 340 x 55 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 190 mm |
| Outer diameter D | 340 mm |
| Width B | 55 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 335 kN |
| Basic static load rating C0 | 390 kN |
| Fatigue load limit Pu | 17.9 kN |
| Limiting speed (mechanical) | 2000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 21300 g |
| Manufacturer designation | NTN 7238 |
| 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 | 7.48 in |
|---|---|
| Outer diameter D | 13.386 in |
| Width B | 2.165 in |
| ISO bore code | 38 |
| Radial section height (D−d)/2 | 75 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) | 31 of 36 |
| Bore above smallest 7200-series size | 180 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 7238 model number is decoded
7238 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 190 x 340 x 55 mm. Reading the code: 72 is the single-row dimension series (medium-duty 7200 single-row family), 38 encodes the 190 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 radial section height here is 75.0 mm, and the catalogue couples that with C 335 kN / C0 390 kN. When axial load reverses, specify the bearing as a matched pair (DB, DF or DT) instead of two random singles — the catalogue right-hand columns give the paired ratings for exactly this reason. Shaft and housing shoulders must clear the ring corners yet support enough face — the catalogue abutment diameters for the 190 mm bore give the working limits.
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
- thermal runaway from excessive preload: the pair runs hot, grease darkens and the contact ellipse spreads until the raceways smear
- resin-cage cracking on the 7900-series sizes after hot, dry running or solvent attack on the polymer
- lubricant starvation scoring at the ball/raceway contact when grease volume or relubrication interval is guessed instead of calculated
- 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 190 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.
- Grease rated for deep-groove motor duty is not automatically right at 2,000 r/min with preload; check the grease speed factor against the catalogue figure.
- On a 190 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.
- 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 335/390 kN ratings and 17.9 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7238; 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 7238?
7238 is a single-row angular contact ball bearing to ISO 15: 190 mm bore, 340 mm outside diameter, 55 mm width (7.48 x 13.386 x 2.165 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 335 kN, C0 390 kN and a 17.9 kN fatigue load limit Pu; the grease limiting speed is 2,000 r/min and the oil rating 2,600 r/min; mass about 21300 g.
How is the 7238 designation structured?
72 is the single-row dimension series (medium-duty 7200 single-row family); 38 encodes the 190 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 340 mm OD and 55 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7238 support?
One 7238 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 7238?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 2,000 r/min and the oil rating 2,600 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 7238?
The 190/340/55 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 335 kN / C0 390 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.