33124U bearing: complete specifications & equivalents
The 33124U is a ISO 355 radial bearing sized 120 x 200 x 62 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 120 mm |
| Outer diameter D | 200 mm |
| Width B | 62 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 510 kN |
| Basic static load rating C0 | 760 kN |
| Fatigue load limit Pu | 80.5 kN |
| Limiting speed (mechanical) | 1800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 7670 g |
| Manufacturer designation | NTN 33124U |
| 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 & 33100-series range
| Bore d | 4.724 in |
|---|---|
| Outer diameter D | 7.874 in |
| Width B | 2.441 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in 33100-series | 40 mm |
| Largest outer diameter in 33100-series | 200 mm |
| Width range across 33100-series | 26–62 mm |
| Bore position in 33100-series (smallest first) | 13 of 13 |
| Bore above smallest 33100-series size | 80 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 33124U | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 33124U model number is decoded
33124U is a metric single-row tapered roller bearing in the NTN 4T programme: a pressed-steel cage guides profiled rollers between a separable cone and cup on the 120×200 mm ISO 355 envelope, with 62 mm overall assembled width T. On the NTN nameplate the parts carry 4T plus the bare code, while 2203E orders 33124U by the metric ISO 355 number (ISO series abbreviation 3FE): 120 mm bore, 200 mm OD. NTN grades 4T metric bearings as open bearings without integral seals; at 120 mm bore the application supplies the seals and the grease fill or oil supply to the 3FE ISO 355 assembly. Grease relubrication at 1,800 r/min limiting speed targets the rib contact; if the drive needs 2,300 r/min it must be arranged for oil lubrication with a defined flow to the large roller ends. Re-adjustment after bedding-in is standard practice: re-check end play once the paired 33124U arrangement has run in, because initial seat seating relaxes the set preload slightly.
Typical equipment & failure modes
Common applications
- rolling-mill roll-neck and gearbox positions
- large crusher and SAG/AG-mill drive shafts
- wind-turbine gearbox and main-shaft arrangements
- offshore crane and drawworks drums
Known failure patterns
- cup creep and housing fretting when the specified outer-ring press fit is not achieved
- preload loss from racewear when one bearing of the paired set is replaced without re-adjusting end play
- rib scoring when axial load is carried beyond the cone rib capacity of the adjusted pair
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- fretting corrosion on a loose cone seat that creeps under rotating load
Selection pitfalls — read before you substitute
- At 120 mm bore the 33124U set is adjusted with hydraulic nuts on large mill and wind positions; follow the drive-up angle/end-play procedure, because manual torque methods cannot control preload at the 510 kN C level.
- The light-wide 33100 family at 120 mm bore (200×62 mm assembled) carries more capacity than the lighter 320/329 sections but generates more preload heat; confirm oil availability before running near the 2,300 r/min oil ceiling.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 120 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- On slash-size and T-code bearings confirm the full code on both cone and cup before fitting: the 120 mm bore alone does not identify the cup, and a mismatched cone/cup set has no catalogue rating.
- The 40.0 mm section leaves little room for an oversized shaft fillet; check the mounting-chamfer table for 33124U or the ring will bottom out on the radius instead of the shoulder face.
- The 510/760 kN ratings and 80.5 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 33124U (ISO 355 3FE); 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 33124U?
33124U is a metric 4T tapered roller bearing to ISO 355: 120 mm bore, 200 mm outside diameter and 62 mm assembled width T (4.724 × 7.874 × 2.441 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 510 kN, C0 760 kN, Pu 80.5 kN, grease limiting speed 1,800 r/min, oil speed 2,300 r/min, mass about 7670 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 33124U?
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 (33124U); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 33124U designation encode the 120 mm bore and what is 3FE?
last two digits 24 are the ISO bore code, ×5 = 120 mm (codes 00–03 use the 10/12/15/17 exception table). The 200 mm OD and 62 mm assembled T follow the ISO 355 dimension-series plan. 3FE 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 33124U list two speeds, 1,800 and 2,300 r/min?
The lower figure, 1,800 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 33124U at 2,300 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 33124U mean?
Suffix reading on 33124U: U marks the reinforced/uprated internal design of the bare number, a separate order number with higher load capacity than the basic execution; the suffix is part of the order number and the variants are not interchangeable articles.
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.