QJ224 bearing: complete specifications & equivalents
The QJ224 is a ISO 15 radial bearing sized 120 x 215 x 40 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 120 mm |
| Outer diameter D | 215 mm |
| Width B | 40 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 266 kN |
| Basic static load rating C0 | 540 kN |
| Fatigue load limit Pu | 17.7 kN |
| Limiting speed (mechanical) | 2300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6750 g |
| Manufacturer designation | NTN QJ224 |
| 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 & QJ200-series range
| Bore d | 4.724 in |
|---|---|
| Outer diameter D | 8.465 in |
| Width B | 1.575 in |
| ISO bore code | 24 |
| Radial section height (D−d)/2 | 47.5 mm |
| Smallest bore in QJ200-series | 15 mm |
| Largest outer diameter in QJ200-series | 360 mm |
| Width range across QJ200-series | 11–58 mm |
| Bore position in QJ200-series (smallest first) | 21 of 29 |
| Bore above smallest QJ200-series size | 105 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the QJ224 model number is decoded
From the medium-duty QJ200 four-point family, QJ224 measures 120 mm across the bore, 215 mm over the outer ring and 40 mm across the faces. NTN builds the number from QJ2 is the four-point dimension series (medium-duty QJ200 four-point family), then the last two digits 24 give the bore by the standard code table (120 mm); there is no suffix — the split inner ring and 35 deg contact angle are inherent to the QJ design. NTN prints 266 kN dynamic and 540 kN static for this size and a 17.7 kN fatigue load limit Pu. Where the same envelope must also be sealed, or where mounting mistakes are likely, compare with the double-row 52/53 catalogue pages before fixing the bill of materials. Grease quantity matters as much as grade at 2,300 r/min: fill about a third of the free space and let the bearing purge on first run.
Typical equipment & failure modes
Common applications
- steel-plant conveyor and table roll drives
- wind-turbine and heavy-machinery auxiliaries
- heavy industrial gearbox main shafts
- large fan, blower and turbo-compressor rotors
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
- contamination-induced denting — hard particles rolled into the contact ellipse become the initiation points for surface fatigue
- 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 120 mm bore bearing forgives nothing in a poorly machined housing.
- The QJ split inner ring must be clamped by the shaft nut/shoulder on both halves — assembling it against a single small shoulder leaves one half-ring free to walk.
- A QJ224 mounted the wrong way round still turns smoothly by hand; the failure shows up weeks later as raceway flaking on the unloaded-looking side.
- 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 QJ224 without re-checking axial float, heat and housing width — the kinematics differ.
- The 266/540 kN ratings and 17.7 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for QJ224; 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 QJ224?
QJ224 is a four-point contact ball bearing to ISO 15: 120 mm bore, 215 mm outside diameter, 40 mm width (4.724 x 8.465 x 1.575 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 266 kN, C0 540 kN and a 17.7 kN fatigue load limit Pu; the grease limiting speed is 2,300 r/min and the oil rating 3,100 r/min; mass about 6750 g.
How is the QJ224 designation structured?
QJ2 is the four-point dimension series (medium-duty QJ200 four-point family); the last two digits 24 give the bore by the standard code table (120 mm); there is no suffix — the split inner ring and 35 deg contact angle are inherent to the QJ design. The 215 mm OD and 40 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does QJ224 support?
QJ224 is a four-point contact bearing: the split inner ring lets each ball touch the raceways at two points, so one bearing locates the shaft in both axial directions at its 35 deg contact angle. It is normally mounted with slight radial clearance against the housing as the axial-locating member.
What lubrication speeds does NTN print for QJ224?
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 QJ224?
The 120/215/40 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 266 kN / C0 540 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.