33008 bearing: complete specifications & equivalents
The 33008 is a ISO 355 radial bearing sized 40 x 68 x 22 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 | 22 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 66 kN |
| Basic static load rating C0 | 82.5 kN |
| Limiting speed (mechanical) | 5300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 320 g |
| Manufacturer designation | NTN 33008 |
| Standard | ISO 355 |
| 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 & 33000-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.677 in |
| Width B | 0.866 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 14 mm |
| Smallest bore in 33000-series | 25 mm |
| Largest outer diameter in 33000-series | 225 mm |
| Width range across 33000-series | 17–59 mm |
| Bore position in 33000-series (smallest first) | 4 of 24 |
| Bore above smallest 33000-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33008 | 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 33008 model number is decoded
For a 40 mm shaft with a thrust component, NTN lists 33008, a metric 4T tapered roller bearing of 66 kN C and 82.5 kN C0 inside the 68 mm OD, 22 mm-wide assembled set. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 33008 resolves to 40 mm bore; the NTN factory mark 4T is stamped on cone and cup but is a brand mark, not a size code, so the catalogue sku is printed without it. Individually mounted, 33008 takes axial force in one direction only; two bearings are arranged face-to-face (X) or back-to-back (O) according to the moment stiffness and misalignment the shaft requires. Catalogue mass of the 33008 set is 320 g (0.013 lb cone + cup); abutment and shaft shoulder design must carry that mass square to the axis. When pairing 33008 with a second tapered bearing, keep the matched arrangement clean: a single stray grit particle between cup and housing changes preload faster than the adjustment range can correct.
Typical equipment & failure modes
Common applications
- bevel and helical pinion drives with high thrust component
- pump and compressor drive shafts carrying combined load
- machine-tool gearbox and headstock shafts
- axle final-drive and differential positions
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- cage damage from a mounting blow delivered through the roller complement instead of the ring face
- rolling-contact fatigue after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- Hub and pinion bearings of this 40 mm bore class are commonly adjusted in pairs; verify end play against the axle drawing and re-torque after bedding-in rather than trusting the initial preload on 33008.
- The thin 22 mm section of 33008 is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 40 mm bore smears the roller ends against the rib.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 40 mm shoulder geometry, because retrofitting flips the cups.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 40 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- Never fit the 40 mm cone by hammering the 68 mm cup: force for both press fits goes through the ring faces only, or brinell marks release as noise within the first running hours.
- The 66/82.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 33008 (ISO 355 2BE); internal geometry legitimately differs between manufacturers, so re-verify ratings, adjustment and suffix before substituting another make on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 33008?
33008 is a metric 4T tapered roller bearing to ISO 355: 40 mm bore, 68 mm outside diameter and 22 mm assembled width T (1.575 × 2.677 × 0.866 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 66 kN, C0 82.5 kN (2203E prints no Pu for this size), grease limiting speed 5,300 r/min, oil speed 7,100 r/min, mass about 320 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 33008?
4T is NTN's tapered roller bearing brand mark, stamped on the cone and cup in the factory. It identifies the NTN 4T programme and is not a dimension, so the catalogue and this page list the bare ISO 355 number (33008); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 33008 designation encode the 40 mm bore and what is 2BE?
last two digits 08 are the ISO bore code, ×5 = 40 mm (codes 00–03 use the 10/12/15/17 exception table). The 68 mm OD and 22 mm assembled T follow the ISO 355 dimension-series plan. 2BE is the maker-neutral ISO 355 abbreviation for this dimension series (the same code other manufacturers print); 4T is NTN's own brand mark.
Why does 33008 list two speeds, 5,300 and 7,100 r/min?
The lower figure, 5,300 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 33008 at 7,100 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 33008 mean?
It is the basic open 4T execution — steel cage, adjusted mounting, no seal or feature suffix. NTN uses U for the uprated design, UTG for ULTAGE large-bearing specs, X for the ISO boundary section, and C/CA/D/A for contact-angle or internal-design variants; all are separate order numbers.
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.