5306S bearing: complete specifications & equivalents
The 5306S is a ISO 15 radial bearing sized 30 x 72 x 30.2 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 30 mm |
| Outer diameter D | 72 mm |
| Width B | 30.2 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 40.5 kN |
| Basic static load rating C0 | 28.1 kN |
| Fatigue load limit Pu | 1.7 kN |
| Limiting speed (mechanical) | 6300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 570 g |
| Manufacturer designation | NTN 5306S |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 2.835 in |
| Width B | 1.189 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 21 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) | 5 of 13 |
| Bore above smallest 5300S-series size | 15 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 5306S model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 5306S appears as a heavy-duty 5300S double-row family bearing of 30 mm bore, 72 mm outside diameter and 30.2 mm width. NTN builds the number from 53 is the double-row dimension series (heavy-duty 5300S double-row family), then 06 encodes the 30 mm bore (bore code x 5), and the trailing S marks the current internal design of the family. On speed, the grease limiting speed is 6,300 r/min and the oil rating 8,500 r/min. Size selection is usually finished by checking that the C0 of 28.1 kN covers the maximum static or shock condition with the catalogue safety factor, not only the running load. Grease quantity matters as much as grade at 6,300 r/min: fill about a third of the free space and let the bearing purge on first run.
Typical equipment & failure modes
Common applications
- electric motor shafts with axial locating duty
- conveyor drive and tension-drum shafts
- agricultural gearbox and PTO shaft supports
- printing-press cylinder and folder shafts
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
- machined-cage land scoring when a high-speed spindle runs past its grease rating and the cage runs dry on its guidance surface
- lubricant starvation scoring at the ball/raceway contact when grease volume or relubrication interval is guessed instead of calculated
- 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
- In this size class the common miss is lubrication interval, not fit — a 30 mm spindle at the catalogue speeds needs a calculated relubrication plan, not a calendar one.
- 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.
- Grease rated for deep-groove motor duty is not automatically right at 6,300 r/min with preload; check the grease speed factor against the catalogue figure.
- Substituting the B (40 deg) execution for the standard 30 deg bearing changes the axial/radial load split — the shaft position and the mating bearing see different forces even though the envelope is identical.
- The C0 of 28.1 kN is a static rating, not a permissible running thrust — sizing continuous axial load from C0 alone is a recurring drawing-office error.
- The 40.5/28.1 kN ratings and 1.7 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 5306S; 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 5306S?
5306S is a double-row angular contact ball bearing to ISO 15: 30 mm bore, 72 mm outside diameter, 30.2 mm width (1.181 x 2.835 x 1.189 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 40.5 kN, C0 28.1 kN and a 1.7 kN fatigue load limit Pu; the grease limiting speed is 6,300 r/min and the oil rating 8,500 r/min; mass about 570 g.
How is the 5306S designation structured?
53 is the double-row dimension series (heavy-duty 5300S double-row family); 06 encodes the 30 mm bore (bore code x 5), and the trailing S marks the current internal design of the family. The 72 mm OD and 30.2 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 5306S support?
5306S 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 5306S?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 6,300 r/min and the oil rating 8,500 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 5306S?
The 30/72/30.2 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 40.5 kN / C0 28.1 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.