5304S bearing: complete specifications & equivalents
The 5304S is a ISO 15 radial bearing sized 20 x 52 x 22.2 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 20 mm |
| Outer diameter D | 52 mm |
| Width B | 22.2 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 24.6 kN |
| Basic static load rating C0 | 15 kN |
| Fatigue load limit Pu | 0.93 kN |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 220 g |
| Manufacturer designation | NTN 5304S |
| 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 & 5300S-series range
| Bore d | 0.787 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.874 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 16 mm |
| Smallest bore in 5300S-series | 15 mm |
| Largest outer diameter in 5300S-series | 150 mm |
| Width range across 5300S-series | 19–63.5 mm |
| Bore position in 5300S-series (smallest first) | 3 of 13 |
| Bore above smallest 5300S-series size | 5 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 5304S model number is decoded
NTN 5304S belongs to the heavy-duty 5300S double-row family: the catalogue boundary dimensions read 20 / 52 / 22.2 mm (bore / OD / width). The designation breaks down as 53 is the double-row dimension series (heavy-duty 5300S double-row family); 04 encodes the 20 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. If the duty is mainly high speed with modest thrust, the 7900-series cross-section is the lighter alternative; if thrust dominates, the 7300-series section carries more. A 20 mm shaft typically takes a k5/m5 fit for rotating inner-ring load; keep the housing bore to G6/H6 class so the contact geometry is not distorted.
Typical equipment & failure modes
Common applications
- high-speed router, grinder and woodworking spindles
- small pump and compressor shafts with combined load
- servo and stepper motor shafts with axial preload
- bicycle and motorcycle wheel and steering positions
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
- thermal runaway from excessive preload: the pair runs hot, grease darkens and the contact ellipse spreads until the raceways smear
- pressed-steel cage pocket wear and rivet loosening after repeated ball skid at light load and high speed
- edge loading and early spalling from housing bores that are out of round or shoulders that are too small for the ring face
- 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 20 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.
- The 9,000 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.
- 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 9,000 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 24.6/15 kN ratings and 0.93 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 5304S; 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 5304S?
5304S is a double-row angular contact ball bearing to ISO 15: 20 mm bore, 52 mm outside diameter, 22.2 mm width (0.787 x 2.047 x 0.874 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 24.6 kN, C0 15 kN and a 0.93 kN fatigue load limit Pu; the grease limiting speed is 9,000 r/min and the oil rating 12,000 r/min; mass about 220 g.
How is the 5304S designation structured?
53 is the double-row dimension series (heavy-duty 5300S double-row family); 04 encodes the 20 mm bore (bore code x 5), and the trailing S marks the current internal design of the family. The 52 mm OD and 22.2 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 5304S support?
5304S 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 5304S?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 9,000 r/min and the oil rating 12,000 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 5304S?
The 20/52/22.2 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 24.6 kN / C0 15 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.