7208-NTN bearing: complete specifications & equivalents
The 7208-NTN is a ISO 15 radial bearing sized 40 x 80 x 18 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 40 mm |
| Outer diameter D | 80 mm |
| Width B | 18 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 39 kN |
| Basic static load rating C0 | 25.1 kN |
| Fatigue load limit Pu | 1.97 kN |
| Limiting speed (mechanical) | 9600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 355 g |
| Manufacturer designation | NTN 7208 |
| 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 | 1.575 in |
|---|---|
| Outer diameter D | 3.15 in |
| Width B | 0.709 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 20 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) | 9 of 36 |
| Bore above smallest 7200-series size | 30 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 7208-NTN model number is decoded
7208 is an NTN single-row angular contact ball bearing: medium-duty 7200 single-row family, listed in NTN Ball and Roller Bearings CAT.No.2203E at 40 x 80 x 18 mm. Two fields make up the code — 72 is the single-row dimension series (medium-duty 7200 single-row family) and 08 encodes the 40 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 radial section height here is 20.0 mm, and the catalogue couples that with C 39 kN / C0 25.1 kN. The 40/80/18 envelope is an ISO 15 boundary plan, so dimensional interchange with other makers holds — ratings and internal geometry do not automatically follow. A 40 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
- 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
- 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
- edge loading and early spalling from housing bores that are out of round or shoulders that are too small for the ring face
- contamination-induced denting — hard particles rolled into the contact ellipse become the initiation points for surface fatigue
Selection pitfalls — read before you substitute
- In this size class the common miss is lubrication interval, not fit — a 40 mm spindle at the catalogue speeds needs a calculated relubrication plan, not a calendar one.
- 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.
- The 9,600 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.
- On a 40 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.
- 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 39/25.1 kN ratings and 1.97 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7208; 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 7208?
7208 is a single-row angular contact ball bearing to ISO 15: 40 mm bore, 80 mm outside diameter, 18 mm width (1.575 x 3.15 x 0.709 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 39 kN, C0 25.1 kN and a 1.97 kN fatigue load limit Pu; the grease limiting speed is 9,600 r/min and the oil rating 13,000 r/min; mass about 355 g.
How is the 7208 designation structured?
72 is the single-row dimension series (medium-duty 7200 single-row family); 08 encodes the 40 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 80 mm OD and 18 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7208 support?
One 7208 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 7208?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 9,600 r/min and the oil rating 13,000 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 7208?
The 40/80/18 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 39 kN / C0 25.1 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.