32988UTG bearing: complete specifications & equivalents
The 32988UTG is a ISO 355 radial bearing sized 440 x 600 x 100 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 440 mm |
| Outer diameter D | 600 mm |
| Width B | 100 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 2060 kN |
| Basic static load rating C0 | 3450 kN |
| Fatigue load limit Pu | 258 kN |
| Limiting speed (mechanical) | 470 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 76000 g |
| Manufacturer designation | NTN 32988UTG |
| 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 & 32900-series range
| Bore d | 17.323 in |
|---|---|
| Outer diameter D | 23.622 in |
| Width B | 3.937 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 80 mm |
| Smallest bore in 32900-series | 35 mm |
| Largest outer diameter in 32900-series | 600 mm |
| Width range across 32900-series | 14–100 mm |
| Bore position in 32900-series (smallest first) | 37 of 37 |
| Bore above smallest 32900-series size | 405 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 32988UTG | 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 32988UTG model number is decoded
32988UTG belongs to the NTN metric 4T tapered roller range (extra-light thin-section 32900 family); the open bearing leaves sealing to the application and is normally ordered and mounted as an adjustable matched pair. NTN also quotes this bearing with its ISO 355 dimension-series abbreviation which is the maker-neutral cross-reference for the 440×600 mm envelope; 4T is NTN's own tapered-roller brand mark on the parts. Individually mounted, 32988UTG 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 32988UTG set is 76000 g (2.992 lb cone + cup); abutment and shaft shoulder design must carry that mass square to the axis. Open 4T bearings need application seals; without them the grease at the cone rib of 32988UTG washes out and the rib/roller-end contact smears on the first wet or dusty shift.
Typical equipment & failure modes
Common applications
- wind-turbine gearbox and main-shaft arrangements
- offshore crane and drawworks drums
- heavy haul railway traction gearboxes
- large marine propulsion reduction gears
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
- fretting corrosion on a loose cone seat that creeps under rotating load
Selection pitfalls — read before you substitute
- At 440 mm bore the 32988UTG 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 2060 kN C level.
- The thin 100 mm section of 32988UTG is built for low friction and tight envelopes, not the heavy preload of a 322/323 set; over-tightening adjustment on this 440 mm bore smears the roller ends against the rib.
- Grease packs must leave free volume in the 100 mm-wide set; over-greasing a paired bearing churning at the 670 r/min oil-band speed raises temperature and destroys the preload setting.
- ISO 355 makes the 440×600 mm envelope interchangeable but not the ratings: NTN prints 2060/3450 kN for this execution, and a cheaper same-number part can differ in roller complement and steel.
- Never fit the 440 mm cone by hammering the 600 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 2060/3450 kN ratings and 258 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 32988UTG; 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 32988UTG?
32988UTG is a metric 4T tapered roller bearing to ISO 355: 440 mm bore, 600 mm outside diameter and 100 mm assembled width T (17.323 × 23.622 × 3.937 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 2060 kN, C0 3450 kN, Pu 258 kN, grease limiting speed 470 r/min, oil speed 670 r/min, mass about 76000 g. It is an open, separable cone/cup bearing with a pressed-steel cage.
What does the 4T prefix mean on 32988UTG?
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 (32988UTG); the lower-case 4t- factory spelling of the code is retained among the search aliases.
How does the 32988UTG designation encode the 440 mm bore?
last two digits 88 are the ISO bore code, ×5 = 440 mm (codes 00–03 use the 10/12/15/17 exception table). The 600 mm OD and 100 mm assembled T follow the ISO 355 dimension-series plan.
Why does 32988UTG list two speeds, 470 and 670 r/min?
The lower figure, 470 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 32988UTG at 670 r/min because oil removes rib-contact heat better. Real limits still depend on preload, oil flow and cooling.
What does the suffix on 32988UTG mean?
Suffix reading on 32988UTG: 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.