7203-NTN bearing: complete specifications & equivalents
The 7203-NTN is a ISO 15 radial bearing sized 17 x 40 x 12 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 17 mm |
| Outer diameter D | 40 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 13.2 kN |
| Basic static load rating C0 | 6.6 kN |
| Fatigue load limit Pu | 0.52 kN |
| Limiting speed (mechanical) | 19000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 64 g |
| Manufacturer designation | NTN 7203 |
| 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 | 0.669 in |
|---|---|
| Outer diameter D | 1.575 in |
| Width B | 0.472 in |
| ISO bore code | 03 |
| Radial section height (D−d)/2 | 11.5 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) | 4 of 36 |
| Bore above smallest 7200-series size | 7 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 7203-NTN model number is decoded
From the medium-duty 7200 single-row family, 7203 measures 17 mm across the bore, 40 mm over the outer ring and 12 mm across the faces. The designation breaks down as 72 is the single-row dimension series (medium-duty 7200 single-row family); 03 encodes the 17 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 static margin, C0 6.6 kN versus C 13.2 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. Heat-mounting to 80-90 deg C is the clean route onto a 17 mm shaft; drive-fits through the balls transmit force through the contact ellipse and can brinell it.
Typical equipment & failure modes
Common applications
- precision instrument and encoder support shafts
- small machine-tool spindle and live-centre positions
- high-speed router, grinder and woodworking spindles
- small pump and compressor shafts with combined load
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
- 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
- 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 17 mm bore the rings are thin-sectioned: press force must go through the ring being fitted, never through the balls, or the first damage is already in the raceway before the machine runs.
- 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.
- 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 C0 of 6.6 kN is a static rating, not a permissible running thrust — sizing continuous axial load from C0 alone is a recurring drawing-office error.
- Do not pair two random 7203 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 13.2/6.6 kN ratings and 0.52 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7203; 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 7203?
7203 is a single-row angular contact ball bearing to ISO 15: 17 mm bore, 40 mm outside diameter, 12 mm width (0.669 x 1.575 x 0.472 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 13.2 kN, C0 6.6 kN and a 0.52 kN fatigue load limit Pu; the grease limiting speed is 19,000 r/min and the oil rating 26,000 r/min; mass about 64 g.
How is the 7203 designation structured?
72 is the single-row dimension series (medium-duty 7200 single-row family); 03 encodes the 17 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 40 mm OD and 12 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7203 support?
One 7203 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 7203?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 19,000 r/min and the oil rating 26,000 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 7203?
The 17/40/12 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 13.2 kN / C0 6.6 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.