7008-NTN bearing: complete specifications & equivalents
The 7008-NTN is a ISO 15 radial bearing sized 40 x 68 x 15 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 | 68 mm |
| Width B | 15 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 20.8 kN |
| Basic static load rating C0 | 14.6 kN |
| Fatigue load limit Pu | 1.07 kN |
| Limiting speed (mechanical) | 10000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 222 g |
| Manufacturer designation | NTN 7008 |
| 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 & 7000-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.677 in |
| Width B | 0.591 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 14 mm |
| Smallest bore in 7000-series | 10 mm |
| Largest outer diameter in 7000-series | 420 mm |
| Width range across 7000-series | 8–65 mm |
| Bore position in 7000-series (smallest first) | 9 of 36 |
| Bore above smallest 7000-series size | 30 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7008 | GENERIC-ISO | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per 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 7008-NTN model number is decoded
7008 is the 40 mm bore member of NTN's standard-section 7000 single-row family, with a 68 mm outside diameter and 15 mm section width. NTN builds the number from 70 is the single-row dimension series (standard-section 7000 single-row family), then 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 static margin, C0 14.6 kN versus C 20.8 kN, is what supports slow oscillating duty and shock without immediate brinelling. Selection starts from the thrust share: as axial load grows past roughly half the radial load, an angular-contact position of this section usually outlives a deep-groove one. 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
- 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 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.
- A 7008 mounted the wrong way round still turns smoothly by hand; the failure shows up weeks later as raceway flaking on the unloaded-looking side.
- The 10,000 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.
- Do not pair two random 7008 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 20.8/14.6 kN ratings and 1.07 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 7008; 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 7008?
7008 is a single-row angular contact ball bearing to ISO 15: 40 mm bore, 68 mm outside diameter, 15 mm width (1.575 x 2.677 x 0.591 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 20.8 kN, C0 14.6 kN and a 1.07 kN fatigue load limit Pu; the grease limiting speed is 10,000 r/min and the oil rating 14,000 r/min; mass about 222 g.
How is the 7008 designation structured?
70 is the single-row dimension series (standard-section 7000 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 68 mm OD and 15 mm width follow the ISO 15 boundary-dimension plan for that series.
Which axial direction does 7008 support?
One 7008 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 7008?
Per NTN Ball and Roller Bearings CAT.No.2203E, the grease limiting speed is 10,000 r/min and the oil rating 14,000 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 7008?
The 40/68/15 mm envelope is ISO 15 interchangeable, but internal geometry — contact angle, osculation, cage and shoulder details — is maker-specific. Re-verify C 20.8 kN / C0 14.6 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.