33012-NTN bearing: complete specifications & equivalents
The 33012-NTN is a ISO 355 radial bearing sized 60 x 95 x 27 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 60 mm |
| Outer diameter D | 95 mm |
| Width B | 27 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 104 kN |
| Basic static load rating C0 | 145 kN |
| Limiting speed (mechanical) | 3700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 693 g |
| Manufacturer designation | NTN 33012 |
| 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 | 2.362 in |
|---|---|
| Outer diameter D | 3.74 in |
| Width B | 1.063 in |
| ISO bore code | 12 |
| Radial section height (D−d)/2 | 17.5 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) | 8 of 24 |
| Bore above smallest 33000-series size | 35 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33012 | SKF | 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 33012-NTN model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, the NTN order number 33012 denotes the slim 33000 family of metric tapered roller bearings, 60 mm bore, 95 mm outside diameter and 27 mm assembled width T (2.362 × 3.74 × 1.063 in) to the ISO 355 boundary plan. Reading the designation: the leading five digits follow the ISO 355 metric plan (dimension family plus two-digit bore code), and 33012 resolves to 60 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. With no letter after the number, 33012 is the basic open 4T execution: steel cage, normal adjustment, no seal or special internal-design suffix in the order code. The two speed columns differ by a factor of .76 (grease/limiting 3,700 vs oil 4,900 r/min); heat generation at the cone rib decides which lubrication a real 33012 arrangement can sustain. Open 4T bearings need application seals; without them the grease at the cone rib of 33012 washes out and the rib/roller-end contact smears on the first wet or dusty shift.
Typical equipment & failure modes
Common applications
- large agricultural and forestry machine axles
- heavy industrial gearboxes and crane travel drives
- rolling-mill auxiliary and pinion-stand shafts
- large conveyor and bucket-elevator pulleys
Known failure patterns
- cone-raceway spalling at the large rib when preload is set too high for the lubricant film
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- cage fatigue when the pair is run continuously near the grease limiting speed without oil cooling
- rolling-contact fatigue after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- Mount the 60 mm cone by induction heating (max 120 °C) and the cup with a press sleeve; the 693 g ring mass makes cocking during fitting a direct raceway-brinelling risk.
- The thin 27 mm section of 33012 is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 60 mm bore smears the roller ends against the rib.
- Do not confuse T (27 mm assembled width of cone + cup) with the cone width when drawing spacers; an abutment sized to T instead of the ring width leaves the cup unseated.
- Grease packs must leave free volume in the 27 mm-wide set; over-greasing a paired bearing churning at the 4,900 r/min oil-band speed raises temperature and destroys the preload setting.
- ISO 355 makes the 60×95 mm envelope interchangeable but not the ratings: NTN prints 104/145 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- The 104/145 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 33012 (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 33012?
33012 is a metric 4T tapered roller bearing to ISO 355: 60 mm bore, 95 mm outside diameter and 27 mm assembled width T (2.362 × 3.74 × 1.063 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 104 kN, C0 145 kN (2203E prints no Pu for this size), grease limiting speed 3,700 r/min, oil speed 4,900 r/min, mass about 693 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 33012?
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 (33012); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 33012 designation encode the 60 mm bore and what is 2CE?
last two digits 12 are the ISO bore code, ×5 = 60 mm (codes 00–03 use the 10/12/15/17 exception table). The 95 mm OD and 27 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 33012 list two speeds, 3,700 and 4,900 r/min?
The lower figure, 3,700 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 33012 at 4,900 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 33012 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.