99550-99100 bearing: complete specifications & equivalents
The 99550-99100 is a ANSI ABMA 19.2 radial bearing sized 142.875 x 254 x 66.675 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 142.875 mm |
| Outer diameter D | 254 mm |
| Width B | 66.675 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 610 kN |
| Basic static load rating C0 | 910 kN |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 14300 g |
| Manufacturer designation | NTN 4T-99550/99100 |
| Standard | ANSI ABMA 19.2 |
| Catalog version | NTN 2203E 2026-09-25 |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN 2203E 2026-09-25) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN 2203E 2026-09-25); 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 & 4t-inch-series range
| Bore d | 5.625 in |
|---|---|
| Outer diameter D | 10 in |
| Width B | 2.625 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 55.6 mm |
| Smallest bore in 4t-inch-series | 12.7 mm |
| Largest outer diameter in 4t-inch-series | 260 mm |
| Width range across 4t-inch-series | 10.998–77.788 mm |
| Bore position in 4t-inch-series (smallest first) | 139 of 148 |
| Bore above smallest 4t-inch-series size | 130.175 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 99550 | 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 99550-99100 model number is decoded
The NTN 2203E inch table prints 4T-99550/99100 at 142.875 mm bore (5.625 in), 254 mm cup OD and 66.675 mm assembled T, with a grease limiting speed of 1,400 r/min and an oil ceiling of 1,800 r/min. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: 99550 identifies the cone of 142.875 mm (5.625 in) bore by catalogue lookup, and 99100 fixes the 254 mm OD. The 55.6 mm radial section over the 142.875 mm bore positions the contact line of the pair; abutment shoulders and spacers are dimensioned from that geometry, not from the bore alone. The printed 610/910 kN ratings belong to the assembled 99550+99100 pair; a sibling row using the same cone with a different cup carries its own rating row because the raceway track shifts with the cup. NTN grades inch 4T bearings as open bearings without integral seals; at 142.875 mm bore the application supplies sealing and the grease fill or oil feed.
Typical equipment & failure modes
Common applications
- cement-plant mill and kiln drive trains
- large shredder and recycler main shafts
- power-plant coal-mill and fan shafts
- rolling-mill pinion stands and roll-neck auxiliaries
Known failure patterns
- rib-face scoring when the thrust share of the combined load exceeds what the cone rib of this size carries
- cup creep and housing fretting when the cup seat is cut too loose for the rotating load
- flaking on one cone only when a bent shaft loads the O/X pair unevenly
- cage damage from a mounting blow transmitted through the roller complement
- water-induced pitting when the open bearing sees washdown without external seals
Selection pitfalls — read before you substitute
- At 142.875 mm bore the 4T-99550/99100 set is adjusted with hydraulic nuts or measured shims on mill and crane positions; manual torque methods cannot control preload at the 610 kN C level.
- The pure-numeric inch family at 142.875 mm bore (254×66.675 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full 99550/99100 reference at purchase.
- Inch and metric bores collide on paper — 142.875 mm is 5.625 in, not a round metric size; a metric bearing that seems 0.1 mm off will not seat on the inch shaft.
- Grease packs must leave free volume inside the 66.675 mm-wide set; over-greasing a pair churning near the oil-band speed of 1,800 r/min raises temperature and destroys the setting.
- Open 4T-99550/99100 sets have no seals: a hub or gearbox needs external sealing or the 1,400 r/min grease figure is meaningless once water reaches the cone rib.
- The 610/910 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-99550/99100; internal geometry legitimately differs between inch-series makers, so re-verify ratings, adjustment and the exact cone/cup references before substituting another brand on a rated drive.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 4T-99550/99100?
4T-99550/99100 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 142.875 mm bore (5.625 in), 254 mm outside diameter and 66.675 mm assembled width T (10 × 2.625 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 610 kN, C0 910 kN, grease limiting speed 1,400 r/min, oil speed 1,800 r/min, mass about 14300 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-99550/99100 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the 99550 cone or the 99100 cup can be replaced by an identical reference from NTN or another ABMA-dimensioned maker. Pairing the cone with a different cup reference is a different catalogue row: OD, assembled T and the 610/910 kN ratings change with the cup.
What is the difference between 4T-99550/99100 and a metric ISO 355 tapered bearing?
4T-99550/99100 follows the ABMA inch boundary plan with cone/cup references; ISO 355 bearings use metric dimension-series numbers (302, 322, …). Even where a metric size looks close to 142.875×254×66.675 mm, the envelopes and contact angles differ — the two systems are not drop-in interchangeable; check every boundary value before substituting.
What does the 4T prefix on 4T-99550/99100 mean?
4T is NTN's tapered roller bearing quality mark, stamped on cone and cup in the factory. It identifies NTN's 4T programme and is not a dimension or variant code, so interchange lists quote the bare 99550/99100 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-99550/99100 list two speeds, 1,400 and 1,800 r/min?
The lower figure, 1,400 r/min, is the grease-lubricated limiting speed — the mechanical ceiling for the cage, rollers and cone-rib contact. With oil lubrication NTN rates 4T-99550/99100 at 1,800 r/min because oil removes rib-contact heat better. Real limits still depend on pair adjustment, oil flow and cooling.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN 2203E 2026-09-25 on 2026-10-01. Read our editorial & correction policy.