33006 bearing: complete specifications & equivalents
The 33006 is a ISO 355 radial bearing sized 30 x 55 x 20 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 | 55 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 47 kN |
| Basic static load rating C0 | 54 kN |
| Limiting speed (mechanical) | 6900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 201 g |
| Manufacturer designation | NTN 33006 |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 2.165 in |
| Width B | 0.787 in |
| ISO bore code | 06 |
| Radial section height (D−d)/2 | 12.5 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) | 2 of 24 |
| Bore above smallest 33000-series size | 5 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33006 | 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 33006 model number is decoded
33006 is the NTN 4T catalogue entry for a 30×55×20 mm metric tapered roller bearing — separable cone and cup, designed for combined radial and axial load as an individually adjusted bearing. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation, 2CE, which is the maker-neutral cross-reference for the 30×55 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. 2203E lists two speed ceilings for 33006: 6,900 r/min with grease lubrication (the limiting speed) and 9,200 r/min with oil, the higher oil value reflecting better heat removal from the cone rib. Imperial cross-check for the drawing: 30×55×20 mm is 1.181 × 2.165 × 0.787 in; ISO 355 makes the envelope interchangeable but C/C0, 47/54 kN, is NTN-specific. Re-adjustment after bedding-in is standard practice: re-check end play once the paired 33006 arrangement has run in, because initial seat seating relaxes the set preload slightly.
Typical equipment & failure modes
Common applications
- axle final-drive and differential positions
- construction-equipment wheel and pivot hubs
- truck and bus wheel hubs in paired arrangements
- industrial gearbox and speed-reducer shafts
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- smearing on the roller large ends and cone rib after a dry start with preload but no oil film
- flaking on one cone only when a back-to-back / face-to-face pair is loaded unevenly by a bent shaft
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- edge loading when shaft deflection exceeds the few arc-minutes of misalignment the adjusted pair allows
Selection pitfalls — read before you substitute
- Hub and pinion bearings of this 30 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 33006.
- The thin 20 mm section of 33006 is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 30 mm bore smears the roller ends against the rib.
- Replacing one half of an adjusted pair without resetting end play negates the 20 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Grease packs must leave free volume in the 20 mm-wide set; over-greasing a paired bearing churning at the 9,200 r/min oil-band speed raises temperature and destroys the preload setting.
- Grease packs must leave free volume in the 20 mm-wide set; over-greasing a paired bearing churning at the 9,200 r/min oil-band speed raises temperature and destroys the preload setting.
- The 47/54 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 33006 (ISO 355 2CE); 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 33006?
33006 is a metric 4T tapered roller bearing to ISO 355: 30 mm bore, 55 mm outside diameter and 20 mm assembled width T (1.181 × 2.165 × 0.787 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 47 kN, C0 54 kN (2203E prints no Pu for this size), grease limiting speed 6,900 r/min, oil speed 9,200 r/min, mass about 201 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 33006?
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 (33006); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 33006 designation encode the 30 mm bore and what is 2CE?
last two digits 06 are the ISO bore code, ×5 = 30 mm (codes 00–03 use the 10/12/15/17 exception table). The 55 mm OD and 20 mm assembled T follow the ISO 355 dimension-series plan. 2CE 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 33006 list two speeds, 6,900 and 9,200 r/min?
The lower figure, 6,900 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 33006 at 9,200 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 33006 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.