30344UTG bearing: complete specifications & equivalents
The 30344UTG is a ISO 355 radial bearing sized 220 x 460 x 97 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 220 mm |
| Outer diameter D | 460 mm |
| Width B | 97 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1620 kN |
| Basic static load rating C0 | 1690 kN |
| Fatigue load limit Pu | 142 kN |
| Limiting speed (mechanical) | 770 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 66600 g |
| Manufacturer designation | NTN 30344UTG |
| 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 & 30300-series range
| Bore d | 8.661 in |
|---|---|
| Outer diameter D | 18.11 in |
| Width B | 3.819 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 120 mm |
| Smallest bore in 30300-series | 15 mm |
| Largest outer diameter in 30300-series | 500 mm |
| Width range across 30300-series | 14.25–105 mm |
| Bore position in 30300-series (smallest first) | 31 of 32 |
| Bore above smallest 30300-series size | 205 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 30344UTG | 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 30344UTG model number is decoded
The NTN 2203E table prints 30344UTG in the large-OD 30300 family with the steeper contact angle: 220 mm bore, 460 mm cup OD, 97 mm T, with a grease limiting speed of 770 r/min and an oil-lubricated ceiling of 1,100 r/min. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation which is the maker-neutral cross-reference for the 220×460 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. The rollers run with their large ends against the cone's integral guide rib; the rib/end-flange contact carries the thrust component and is the reason lubricant must reach the rib face of 30344UTG, not only the raceway. Grease relubrication at 770 r/min limiting speed targets the rib contact; if the drive needs 1,100 r/min it must be arranged for oil lubrication with a defined flow to the large roller ends. With a rotating shaft a m6/n6 shaft seat and a press-fit cup are typical catalogue practice for 30344UTG; reverse the logic if the cup rotates, and re-verify against load direction and magnitude.
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
- 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
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- rolling-contact fatigue after the catalogue L10 life at the actual combined load
Selection pitfalls — read before you substitute
- At 220 mm bore the 30344UTG 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 1620 kN C level.
- The steeper contact angle of the large-OD 30300 family with the steeper contact angle raises axial capacity but lowers the speed ceiling against a 302/322 bearing at 220 mm bore; do not swap to the lighter family without re-checking the 770 r/min grease limit and the thrust load split.
- Replacing one half of an adjusted pair without resetting end play negates the 97 mm T dimension logic: re-adjust the set and re-verify the contact pattern rather than reusing the old spacer stack.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 220 mm shoulder geometry, because retrofitting flips the cups.
- Back-to-back and face-to-face arrangements react differently to shaft bending: pick the pair orientation for the moment load before locking the 220 mm shoulder geometry, because retrofitting flips the cups.
- The 1620/1690 kN ratings and 142 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 30344UTG; 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 30344UTG?
30344UTG is a metric 4T tapered roller bearing to ISO 355: 220 mm bore, 460 mm outside diameter and 97 mm assembled width T (8.661 × 18.11 × 3.819 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1620 kN, C0 1690 kN, Pu 142 kN, grease limiting speed 770 r/min, oil speed 1,100 r/min, mass about 66600 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 30344UTG?
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 (30344UTG); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 30344UTG designation encode the 220 mm bore?
last two digits 44 are the ISO bore code, ×5 = 220 mm (codes 00–03 use the 10/12/15/17 exception table). The 460 mm OD and 97 mm assembled T follow the ISO 355 dimension-series plan.
Why does 30344UTG list two speeds, 770 and 1,100 r/min?
The lower figure, 770 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 30344UTG at 1,100 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 30344UTG mean?
Suffix reading on 30344UTG: the UTG suffix marks the ULTAGE specification for large NTN tapered rollers — upgraded material and internal design for longer life inside the unchanged ISO 355 envelope; 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.