LM603049-LM603011 bearing: complete specifications & equivalents
The LM603049-LM603011 is a ANSI ABMA 19.2 radial bearing sized 45.242 x 77.788 x 19.842 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 45.242 mm |
| Outer diameter D | 77.788 mm |
| Width B | 19.842 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 63.5 kN |
| Basic static load rating C0 | 73.5 kN |
| Limiting speed (mechanical) | 4600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 371 g |
| Manufacturer designation | NTN 4T-LM603049/LM603011 |
| 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 | 1.781 in |
|---|---|
| Outer diameter D | 3.063 in |
| Width B | 0.781 in |
| ISO bore code | 49 |
| Radial section height (D−d)/2 | 16.3 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) | 55 of 148 |
| Bore above smallest 4t-inch-series size | 32.542 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| LM603049-011 | 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. |
| LM603049-011AA | 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. |
| LM603049-012 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | Model-number interchange per ISO 15; confirm dimensions, sealing and ratings in the supplier catalogue. |
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 LM603049-LM603011 model number is decoded
4T-LM603049/LM603011 is the NTN 4T catalogue entry for a 45.242×77.788×19.842 mm inch tapered roller bearing — an ABMA-dimensioned cone/cup set, not an ISO 355 metric bearing, even though the table quotes metric equivalents. Unlike ISO 355 metric numbers, this ABMA code does not encode the bore arithmetically: LM603049 identifies the cone of 45.242 mm (1.781 in) bore by catalogue lookup, and LM603011 fixes the 77.788 mm OD. Contact-angle geometry of the light-medium LM family gives 4T-LM603049/LM603011 its radial/axial load split — at 63.5/73.5 kN the static rating is about 1.16× C, typical of inch tapered sets proportioned for combined duty. Housing fitment sequence for 4T-LM603049/LM603011: press the LM603011 cup square into the 77.788 mm seat first, then bring the LM603049 cone (on its 45.242 mm shaft) into adjustment — the two references are separate engineering parts that happen to ship as one set. Back-to-back (O) and face-to-face (X) arrangements of two 4T-LM603049/LM603011 sets react differently to shaft bending; choose the orientation for the moment load before locking shoulder geometry.
Typical equipment & failure modes
Common applications
- mining and quarry conveyor drive pulleys
- machine-tool headstocks on inch spindles
- pump and blower drive shafts with combined load
- truck and trailer axle hubs on inch-dimensioned axles
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
- pressed-steel cage pocket wear from roller skid at light radial load and high speed
- edge loading when shaft deflection exceeds the few arc-minutes an adjusted pair tolerates
Selection pitfalls — read before you substitute
- Hub and pinion positions of this 45.242 mm class are adjusted in pairs; verify end play against the axle or gearbox drawing and re-torque after bedding-in instead of trusting the first setting on 4T-LM603049/LM603011.
- The light-medium LM family at 45.242 mm bore (77.788×19.842 mm assembled) is one of several inch families sharing similar bores; cross-series swaps change OD, T and contact angle, so match the full LM603049/LM603011 reference at purchase.
- ABMA makes the 45.242×77.788 mm envelope interchangeable, not the ratings: NTN prints 63.5/73.5 kN for this execution and another make of the same number can differ in roller complement.
- Shaft and housing fillets must clear the ring chamfers of LM603049 and LM603011; use undercut shoulders so the rings seat on the face, not on a radius.
- Do not confuse T (19.842 mm, the assembled cone-plus-cup width) with the cone width when drawing spacers; an abutment sized to T leaves the cup unseated.
- The 63.5/73.5 kN ratings here are NTN Ball and Roller Bearings CAT.No.2203E figures for 4T-LM603049/LM603011; 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-LM603049/LM603011?
4T-LM603049/LM603011 is an inch-series single-row tapered roller bearing to the ABMA boundary plan: 45.242 mm bore (1.781 in), 77.788 mm outside diameter and 19.842 mm assembled width T (3.063 × 0.781 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 63.5 kN, C0 73.5 kN, grease limiting speed 4,600 r/min, oil speed 6,200 r/min, mass about 371 g. It is an open, separable cone/cup set with a pressed-steel cage.
Are the cone and cup of 4T-LM603049/LM603011 interchangeable separately?
Yes — ABMA inch parts are individually interchangeable: the LM603049 cone or the LM603011 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 63.5/73.5 kN ratings change with the cup.
What is the difference between 4T-LM603049/LM603011 and a metric ISO 355 tapered bearing?
4T-LM603049/LM603011 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 45.242×77.788×19.842 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-LM603049/LM603011 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 LM603049/LM603011 references; the 4T spelling is retained among this page's search aliases.
Why does 4T-LM603049/LM603011 list two speeds, 4,600 and 6,200 r/min?
The lower figure, 4,600 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-LM603049/LM603011 at 6,200 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.