5203S bearing: complete specifications & equivalents
The 5203S is a ISO 15 radial bearing sized 17 x 40 x 17.5 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 | 17.5 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 14.6 kN |
| Basic static load rating C0 | 9.05 kN |
| Fatigue load limit Pu | 0.54 kN |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 100 g |
| Manufacturer designation | NTN 5203S |
| 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 & 5200S-series range
| Bore d | 0.669 in |
|---|---|
| Outer diameter D | 1.575 in |
| Width B | 0.689 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 11.5 mm |
| Smallest bore in 5200S-series | 10 mm |
| Largest outer diameter in 5200S-series | 150 mm |
| Width range across 5200S-series | 14.3–49.2 mm |
| Bore position in 5200S-series (smallest first) | 4 of 18 |
| Bore above smallest 5200S-series size | 7 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 5203S | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 5203S model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 5203S appears as a medium-duty 5200S double-row family bearing of 17 mm bore, 40 mm outside diameter and 17.5 mm width. The designation breaks down as 52 is the double-row dimension series (medium-duty 5200S double-row family); 03 encodes the 17 mm bore (bore code x 5), and the trailing S marks the current internal design of the family. Because the contact line is angled, one bearing of this type takes radial load plus thrust from one direction only — the opposite direction needs a second bearing or a matched set. Against a deep-groove bearing of the same 17 mm bore, this bearing trades some pure-radial comfort for real one-direction thrust capacity and higher running accuracy. After mounting, check axial float or preload with a dial gauge on the shaft end — the specification, not hand feel, decides whether the contact angle works as rated.
Typical equipment & failure modes
Common applications
- small machine-tool spindle and live-centre positions
- high-speed router, grinder and woodworking spindles
- small pump and compressor shafts with combined load
- servo and stepper motor shafts with axial preload
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
- machined-cage land scoring when a high-speed spindle runs past its grease rating and the cage runs dry on its guidance surface
- current-erosion pitting on VFD-driven motor shafts, first visible as a grey frosted band across both raceways
- 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 double-row bearing takes reversing thrust in one envelope, but its two contact lines mean more heat than a single row at the same speed — check the thermal balance before copying a single-row speed figure.
- On a 17 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.
- 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 11,000 r/min speed figure assumes the catalogue lubrication state and a correctly set pair; real limits drop fast with excess grease fill or heavy preload.
- The 14.6/9.05 kN ratings and 0.54 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 5203S; 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 5203S?
5203S is a double-row angular contact ball bearing to ISO 15: 17 mm bore, 40 mm outside diameter, 17.5 mm width (0.669 x 1.575 x 0.689 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 14.6 kN, C0 9.05 kN and a 0.54 kN fatigue load limit Pu; the grease limiting speed is 11,000 r/min and the oil rating 15,000 r/min; mass about 100 g.
How is the 5203S designation structured?
52 is the double-row dimension series (medium-duty 5200S double-row family); 03 encodes the 17 mm bore (bore code x 5), and the trailing S marks the current internal design of the family. The 40 mm OD and 17.5 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 5203S support?
5203S is a double-row bearing working like a built-in back-to-back pair: it takes thrust in both directions plus radial load and moment (tilting) load in a single envelope.
What lubrication speeds does NTN print for 5203S?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 11,000 r/min and the oil rating 15,000 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 5203S?
The 17/40/17.5 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 14.6 kN / C0 9.05 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.